/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */


#include "mongo/db/service_entry_point_common.h"

#include <fmt/format.h>

#include "mongo/base/checked_cast.h"
#include "mongo/bson/mutable/document.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/client/server_discovery_monitor.h"
#include "mongo/db/audit.h"
#include "mongo/db/auth/authorization_checks.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/auth/impersonation_session.h"
#include "mongo/db/auth/ldap_cumulative_operation_stats.h"
#include "mongo/db/auth/security_token_authentication_guard.h"
#include "mongo/db/client.h"
#include "mongo/db/command_can_run_here.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/txn_cmds_gen.h"
#include "mongo/db/concurrency/replication_state_transition_lock_guard.h"
#include "mongo/db/curop.h"
#include "mongo/db/curop_failpoint_helpers.h"
#include "mongo/db/curop_metrics.h"
#include "mongo/db/cursor_manager.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/error_labels.h"
#include "mongo/db/initialize_api_parameters.h"
#include "mongo/db/initialize_operation_session_info.h"
#include "mongo/db/introspect.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/logical_time_validator.h"
#include "mongo/db/not_primary_error_tracker.h"
#include "mongo/db/op_observer/op_observer.h"
#include "mongo/db/ops/write_ops.h"
#include "mongo/db/ops/write_ops_exec.h"
#include "mongo/db/query/find.h"
#include "mongo/db/read_concern.h"
#include "mongo/db/read_write_concern_defaults.h"
#include "mongo/db/repl/optime.h"
#include "mongo/db/repl/read_concern_args.h"
#include "mongo/db/repl/repl_client_info.h"
#include "mongo/db/repl/repl_server_parameters_gen.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/repl/speculative_majority_read_info.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/db/repl/tenant_migration_access_blocker_util.h"
#include "mongo/db/request_execution_context.h"
#include "mongo/db/s/operation_sharding_state.h"
#include "mongo/db/s/resharding/resharding_metrics_helpers.h"
#include "mongo/db/s/sharding_cluster_parameters_gen.h"
#include "mongo/db/s/sharding_state.h"
#include "mongo/db/s/sharding_statistics.h"
#include "mongo/db/s/transaction_coordinator_factory.h"
#include "mongo/db/server_feature_flags_gen.h"
#include "mongo/db/service_entry_point_common.h"
#include "mongo/db/session/logical_session_id_helpers.h"
#include "mongo/db/session/session_catalog_mongod.h"
#include "mongo/db/stats/api_version_metrics.h"
#include "mongo/db/stats/counters.h"
#include "mongo/db/stats/resource_consumption_metrics.h"
#include "mongo/db/stats/server_read_concern_metrics.h"
#include "mongo/db/stats/top.h"
#include "mongo/db/transaction/transaction_participant.h"
#include "mongo/db/transaction_validation.h"
#include "mongo/db/vector_clock.h"
#include "mongo/logv2/log.h"
#include "mongo/rpc/check_allowed_op_query_cmd.h"
#include "mongo/rpc/factory.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/rpc/message.h"
#include "mongo/rpc/metadata.h"
#include "mongo/rpc/metadata/client_metadata.h"
#include "mongo/rpc/metadata/oplog_query_metadata.h"
#include "mongo/rpc/metadata/repl_set_metadata.h"
#include "mongo/rpc/metadata/tracking_metadata.h"
#include "mongo/rpc/op_msg.h"
#include "mongo/rpc/reply_builder_interface.h"
#include "mongo/s/query_analysis_sampler.h"
#include "mongo/s/shard_cannot_refresh_due_to_locks_held_exception.h"
#include "mongo/s/sharding_feature_flags_gen.h"
#include "mongo/s/would_change_owning_shard_exception.h"
#include "mongo/transport/hello_metrics.h"
#include "mongo/transport/service_executor.h"
#include "mongo/transport/session.h"
#include "mongo/util/duration.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/future_util.h"
#include "mongo/util/scopeguard.h"

#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kCommand


namespace mongo {

MONGO_FAIL_POINT_DEFINE(respondWithNotPrimaryInCommandDispatch);
MONGO_FAIL_POINT_DEFINE(skipCheckingForNotPrimaryInCommandDispatch);
MONGO_FAIL_POINT_DEFINE(waitAfterNewStatementBlocksBehindPrepare);
MONGO_FAIL_POINT_DEFINE(waitAfterNewStatementBlocksBehindOpenInternalTransactionForRetryableWrite);
MONGO_FAIL_POINT_DEFINE(waitAfterCommandFinishesExecution);
MONGO_FAIL_POINT_DEFINE(failWithErrorCodeInRunCommand);
MONGO_FAIL_POINT_DEFINE(hangBeforeSessionCheckOut);
MONGO_FAIL_POINT_DEFINE(hangAfterSessionCheckOut);
MONGO_FAIL_POINT_DEFINE(hangBeforeSettingTxnInterruptFlag);
MONGO_FAIL_POINT_DEFINE(hangAfterCheckingWritabilityForMultiDocumentTransactions);
MONGO_FAIL_POINT_DEFINE(includeAdditionalParticipantInResponse);

// Tracks the number of times a legacy unacknowledged write failed due to
// not primary error resulted in network disconnection.
CounterMetric notPrimaryLegacyUnackWrites("repl.network.notPrimaryLegacyUnacknowledgedWrites");

// Tracks the number of times an unacknowledged write failed due to not primary error
// resulted in network disconnection.
CounterMetric notPrimaryUnackWrites("repl.network.notPrimaryUnacknowledgedWrites");

namespace {

using namespace fmt::literals;

Future<void> runCommandInvocation(std::shared_ptr<RequestExecutionContext> rec,
                                  std::shared_ptr<CommandInvocation> invocation) {
    auto useDedicatedThread = [&] {
        auto client = rec->getOpCtx()->getClient();
        if (auto context = transport::ServiceExecutorContext::get(client); context) {
            return context->useDedicatedThread();
        }
        tassert(5453901,
                "Threading model may only be absent for internal and direct clients",
                !client->hasRemote() || client->isInDirectClient());
        return true;
    }();
    return CommandHelpers::runCommandInvocation(
        std::move(rec), std::move(invocation), useDedicatedThread);
}

/*
 * Allows for the very complex handleRequest function to be decomposed into parts.
 * It also provides the infrastructure to futurize the process of executing commands.
 */
struct HandleRequest {
    // Maintains the context (e.g., opCtx and replyBuilder) required for command execution.
    class ExecutionContext final : public RequestExecutionContext {
    public:
        ExecutionContext(OperationContext* opCtx,
                         Message msg,
                         std::unique_ptr<const ServiceEntryPointCommon::Hooks> hooks)
            : RequestExecutionContext(opCtx, std::move(msg)), behaviors(std::move(hooks)) {}
        ~ExecutionContext() = default;

        Client& client() const {
            return *getOpCtx()->getClient();
        }

        auto session() const {
            return client().session();
        }

        NetworkOp op() const {
            return getMessage().operation();
        }

        CurOp& currentOp() {
            return *CurOp::get(getOpCtx());
        }

        NamespaceString nsString() const {
            auto& dbmsg = getDbMessage();
            if (!dbmsg.messageShouldHaveNs())
                return {};
            return NamespaceString(dbmsg.getns());
        }

        void assertValidNsString() {
            if (!nsString().isValid()) {
                uassert(16257,
                        str::stream() << "Invalid ns [" << nsString().toStringForErrorMsg() << "]",
                        false);
            }
        }

        /**
         * Note that DBDirectClient is treated as an internal client in relation to letting
         * internal errors escape.
         */
        bool isInternalClient() const {
            return (client().isInDirectClient()) ||
                (session() && (session()->getTags() & transport::Session::kInternalClient));
        }

        std::unique_ptr<const ServiceEntryPointCommon::Hooks> behaviors;
        boost::optional<long long> slowMsOverride;
        bool forceLog = false;
    };

    struct OpRunner {
        explicit OpRunner(HandleRequest* hr) : executionContext{hr->executionContext} {}
        virtual ~OpRunner() = default;
        virtual Future<DbResponse> run() = 0;
        std::shared_ptr<ExecutionContext> executionContext;
    };

    HandleRequest(OperationContext* opCtx,
                  const Message& msg,
                  std::unique_ptr<const ServiceEntryPointCommon::Hooks> behaviors)
        : executionContext(std::make_shared<ExecutionContext>(
              opCtx, const_cast<Message&>(msg), std::move(behaviors))) {}

    std::unique_ptr<OpRunner> makeOpRunner();

    void startOperation();
    void completeOperation(DbResponse&);

    std::shared_ptr<ExecutionContext> executionContext;
};

void registerError(OperationContext* opCtx, const Status& status) {
    NotPrimaryErrorTracker::get(opCtx->getClient()).recordError(status.code());
    CurOp::get(opCtx)->debug().errInfo = status;
}

void generateErrorResponse(OperationContext* opCtx,
                           rpc::ReplyBuilderInterface* replyBuilder,
                           const Status& status,
                           const BSONObj& replyMetadata,
                           BSONObj extraFields = {}) {
    invariant(!status.isOK());
    registerError(opCtx, status);

    // We could have thrown an exception after setting fields in the builder,
    // so we need to reset it to a clean state just to be sure.
    replyBuilder->reset();
    replyBuilder->setCommandReply(status, extraFields);
    replyBuilder->getBodyBuilder().appendElements(replyMetadata);
}

/**
 * Given the specified command, returns an effective read concern which should be used or an error
 * if the read concern is not valid for the command.
 * Note that the validation performed is not necessarily exhaustive.
 */
StatusWith<repl::ReadConcernArgs> _extractReadConcern(OperationContext* opCtx,
                                                      const CommandInvocation* invocation,
                                                      const BSONObj& cmdObj,
                                                      bool startTransaction,
                                                      bool isInternalClient) {
    repl::ReadConcernArgs readConcernArgs;

    auto readConcernParseStatus = readConcernArgs.initialize(cmdObj);
    if (!readConcernParseStatus.isOK()) {
        return readConcernParseStatus;
    }

    // Represents whether the client explicitly defines read concern within the cmdObj or not.
    // It will be set to false also if the client specifies empty read concern {readConcern: {}}.
    bool clientSuppliedReadConcern = !readConcernArgs.isEmpty();
    bool customDefaultWasApplied = false;
    auto readConcernSupport = invocation->supportsReadConcern(readConcernArgs.getLevel(),
                                                              readConcernArgs.isImplicitDefault());

    auto applyDefaultReadConcern = [&](const repl::ReadConcernArgs rcDefault) -> void {
        LOGV2_DEBUG(21955,
                    2,
                    "Applying default readConcern on {command} of {readConcernDefault} "
                    "on {command}",
                    "Applying default readConcern on command",
                    "readConcernDefault"_attr = rcDefault,
                    "command"_attr = invocation->definition()->getName());
        readConcernArgs = std::move(rcDefault);
        // Update the readConcernSupport, since the default RC was applied.
        readConcernSupport =
            invocation->supportsReadConcern(readConcernArgs.getLevel(), !customDefaultWasApplied);
    };

    auto shouldApplyDefaults = (startTransaction || !opCtx->inMultiDocumentTransaction()) &&
        repl::ReplicationCoordinator::get(opCtx)->isReplEnabled() &&
        !opCtx->getClient()->isInDirectClient();

    if (readConcernSupport.defaultReadConcernPermit.isOK() && shouldApplyDefaults) {
        if (isInternalClient) {
            // ReadConcern should always be explicitly specified by operations received from
            // internal clients (ie. from a mongos or mongod), even if it is empty (ie.
            // readConcern: {}, meaning to use the implicit server defaults).
            uassert(
                4569200,
                "received command without explicit readConcern on an internalClient connection {}"_format(
                    redact(cmdObj.toString())),
                readConcernArgs.isSpecified());
        } else if (serverGlobalParams.clusterRole.has(ClusterRole::ShardServer) ||
                   serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer)) {
            if (!readConcernArgs.isSpecified()) {
                // TODO: Disabled until after SERVER-44539, to avoid log spam.
                // LOGV2(21954, "Missing readConcern on {command}", "Missing readConcern "
                // "for command", "command"_attr = invocation->definition()->getName());
            }
        } else {
            // A member in a regular replica set.  Since these servers receive client queries, in
            // this context empty RC (ie. readConcern: {}) means the same as if absent/unspecified,
            // which is to apply the CWRWC defaults if present.  This means we just test isEmpty(),
            // since this covers both isSpecified() && !isSpecified()
            if (readConcernArgs.isEmpty()) {
                const auto rwcDefaults =
                    ReadWriteConcernDefaults::get(opCtx->getServiceContext()).getDefault(opCtx);
                const auto rcDefault = rwcDefaults.getDefaultReadConcern();
                if (rcDefault) {
                    const auto readConcernSource = rwcDefaults.getDefaultReadConcernSource();
                    customDefaultWasApplied =
                        (readConcernSource &&
                         readConcernSource.value() == DefaultReadConcernSourceEnum::kGlobal);

                    applyDefaultReadConcern(*rcDefault);
                }
            }
        }
    }

    // Apply the implicit default read concern even if the command does not support a cluster wide
    // read concern.
    if (!readConcernSupport.defaultReadConcernPermit.isOK() &&
        readConcernSupport.implicitDefaultReadConcernPermit.isOK() && shouldApplyDefaults &&
        !isInternalClient && readConcernArgs.isEmpty()) {
        auto rcDefault = ReadWriteConcernDefaults::get(opCtx->getServiceContext())
                             .getImplicitDefaultReadConcern();
        applyDefaultReadConcern(rcDefault);
    }

    // It's fine for clients to provide any provenance value to mongod. But if they haven't, then an
    // appropriate provenance needs to be determined.
    auto& provenance = readConcernArgs.getProvenance();
    if (!provenance.hasSource()) {
        if (clientSuppliedReadConcern) {
            provenance.setSource(ReadWriteConcernProvenance::Source::clientSupplied);
        } else if (customDefaultWasApplied) {
            provenance.setSource(ReadWriteConcernProvenance::Source::customDefault);
        } else {
            provenance.setSource(ReadWriteConcernProvenance::Source::implicitDefault);
        }
    }

    // If we are starting a transaction, we need to check whether the read concern is
    // appropriate for running a transaction.
    if (startTransaction) {
        if (!isReadConcernLevelAllowedInTransaction(readConcernArgs.getLevel())) {
            return {ErrorCodes::InvalidOptions,
                    "The readConcern level must be either 'local' (default), 'majority' or "
                    "'snapshot' in "
                    "order to run in a transaction"};
        }
        if (readConcernArgs.getArgsOpTime()) {
            return {ErrorCodes::InvalidOptions,
                    str::stream() << "The readConcern cannot specify '"
                                  << repl::ReadConcernArgs::kAfterOpTimeFieldName
                                  << "' in a transaction"};
        }
    }

    // Otherwise, if there is a read concern present - either user-specified or from the default -
    // then check whether the command supports it. If there is no explicit read concern level, then
    // it is implicitly "local". There is no need to check whether this is supported, because all
    // commands either support "local" or upconvert the absent readConcern to a stronger level that
    // they do support; for instance, $changeStream upconverts to RC level "majority".
    //
    // Individual transaction statements are checked later on, after we've unstashed the
    // transaction resources.
    if (!opCtx->inMultiDocumentTransaction() && readConcernArgs.hasLevel()) {
        if (!readConcernSupport.readConcernSupport.isOK()) {
            return readConcernSupport.readConcernSupport.withContext(
                str::stream() << "Command " << invocation->definition()->getName()
                              << " does not support " << readConcernArgs.toString());
        }
    }

    // If this command invocation asked for 'majority' read concern, supports blocking majority
    // reads, and storage engine support for majority reads is disabled, then we set the majority
    // read mechanism appropriately i.e. we utilize "speculative" read behavior.
    if (readConcernArgs.getLevel() == repl::ReadConcernLevel::kMajorityReadConcern &&
        invocation->allowsSpeculativeMajorityReads() &&
        !serverGlobalParams.enableMajorityReadConcern) {
        readConcernArgs.setMajorityReadMechanism(
            repl::ReadConcernArgs::MajorityReadMechanism::kSpeculative);
    }

    return readConcernArgs;
}

/**
 * For replica set members it returns the last known op time from opCtx. Otherwise will return
 * uninitialized cluster time.
 */
LogicalTime getClientOperationTime(OperationContext* opCtx) {
    auto const replCoord = repl::ReplicationCoordinator::get(opCtx);
    const bool isReplSet =
        replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet;

    if (!isReplSet) {
        return LogicalTime();
    }

    return LogicalTime(
        repl::ReplClientInfo::forClient(opCtx->getClient()).getMaxKnownOperationTime());
}

/**
 * Returns the proper operationTime for a command. To construct the operationTime for replica set
 * members, it uses the last optime in the oplog for writes, last committed optime for majority
 * reads, and the last applied optime for every other read. An uninitialized cluster time is
 * returned for non replica set members.
 *
 * The latest in-memory clusterTime is returned if the start operationTime is uninitialized.
 */
LogicalTime computeOperationTime(OperationContext* opCtx, LogicalTime startOperationTime) {
    auto const replCoord = repl::ReplicationCoordinator::get(opCtx);
    const bool isReplSet =
        replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet;
    invariant(isReplSet);

    auto operationTime = getClientOperationTime(opCtx);
    invariant(operationTime >= startOperationTime);

    // If the last operationTime has not changed, consider this command a read, and, for replica set
    // members, construct the operationTime with the proper optime for its read concern level.
    if (operationTime == startOperationTime) {
        auto& readConcernArgs = repl::ReadConcernArgs::get(opCtx);

        // Note: ReadConcernArgs::getLevel returns kLocal if none was set.
        if (readConcernArgs.getLevel() == repl::ReadConcernLevel::kMajorityReadConcern) {
            operationTime =
                LogicalTime(replCoord->getCurrentCommittedSnapshotOpTime().getTimestamp());
        } else {
            operationTime = LogicalTime(replCoord->getMyLastAppliedOpTime().getTimestamp());
        }
    }

    return operationTime;
}

/**
 * Computes the proper $clusterTime and operationTime values to include in the command response and
 * appends them to it. $clusterTime is added as metadata and operationTime as a command body field.
 *
 * The command body BSONObjBuilder is either the builder for the command body itself, or a builder
 * for extra fields to be added to the reply when generating an error response.
 */
void appendClusterAndOperationTime(OperationContext* opCtx,
                                   BSONObjBuilder* commandBodyFieldsBob,
                                   BSONObjBuilder* metadataBob,
                                   LogicalTime startTime) {
    if (repl::ReplicationCoordinator::get(opCtx)->getReplicationMode() !=
            repl::ReplicationCoordinator::modeReplSet ||
        !VectorClock::get(opCtx)->isEnabled()) {
        return;
    }

    // The appended operationTime must always be <= the appended $clusterTime, so first compute the
    // operationTime.
    auto operationTime = computeOperationTime(opCtx, startTime);

    bool clusterTimeWasOutput = VectorClock::get(opCtx)->gossipOut(opCtx, metadataBob);

    // Ensure that either both operationTime and $clusterTime are output, or neither.
    if (clusterTimeWasOutput) {
        operationTime.appendAsOperationTime(metadataBob);
    }
}

void appendErrorLabelsAndTopologyVersion(OperationContext* opCtx,
                                         BSONObjBuilder* commandBodyFieldsBob,
                                         const OperationSessionInfoFromClient& sessionOptions,
                                         const std::string& commandName,
                                         boost::optional<ErrorCodes::Error> code,
                                         boost::optional<ErrorCodes::Error> wcCode,
                                         bool isInternalClient,
                                         const repl::OpTime& lastOpBeforeRun,
                                         const repl::OpTime& lastOpAfterRun) {
    if (!code && !wcCode) {
        return;
    }

    auto errorLabels = getErrorLabels(opCtx,
                                      sessionOptions,
                                      commandName,
                                      code,
                                      wcCode,
                                      isInternalClient,
                                      false /* isMongos */,
                                      lastOpBeforeRun,
                                      lastOpAfterRun);
    commandBodyFieldsBob->appendElements(errorLabels);

    const auto isNotPrimaryError =
        (code && ErrorCodes::isA<ErrorCategory::NotPrimaryError>(*code)) ||
        (wcCode && ErrorCodes::isA<ErrorCategory::NotPrimaryError>(*wcCode));

    const auto isShutdownError = (code && ErrorCodes::isA<ErrorCategory::ShutdownError>(*code)) ||
        (wcCode && ErrorCodes::isA<ErrorCategory::ShutdownError>(*wcCode));

    const auto replCoord = repl::ReplicationCoordinator::get(opCtx);
    // NotPrimary errors always include a topologyVersion, since we increment topologyVersion on
    // stepdown. ShutdownErrors only include a topologyVersion if the server is in quiesce mode,
    // since we only increment the topologyVersion at shutdown and alert waiting isMaster commands
    // if the server enters quiesce mode.
    const auto shouldAppendTopologyVersion =
        (replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet &&
         isNotPrimaryError) ||
        (isShutdownError && replCoord->inQuiesceMode());

    if (!shouldAppendTopologyVersion) {
        return;
    }

    const auto topologyVersion = replCoord->getTopologyVersion();
    BSONObjBuilder topologyVersionBuilder(commandBodyFieldsBob->subobjStart("topologyVersion"));
    topologyVersion.serialize(&topologyVersionBuilder);
}

void appendAdditionalParticipants(OperationContext* opCtx,
                                  BSONObjBuilder* commandBodyFieldsBob,
                                  const std::string& commandName,
                                  StringData ns) {
    // (Ignore FCV check): This feature doesn't have any upgrade/downgrade concerns.
    if (gFeatureFlagAdditionalParticipants.isEnabledAndIgnoreFCVUnsafe()) {
        std::vector<BSONElement> shardIdsFromFpData;
        if (MONGO_unlikely(
                includeAdditionalParticipantInResponse.shouldFail([&](const BSONObj& data) {
                    if (data.hasField("cmdName") && data.hasField("ns") &&
                        data.hasField("shardId")) {
                        shardIdsFromFpData = data.getField("shardId").Array();
                        return ((data.getStringField("cmdName") == commandName) &&
                                (data.getStringField("ns") == ns));
                    }
                    return false;
                }))) {

            std::vector<BSONObj> participantArray;
            for (auto& element : shardIdsFromFpData) {
                auto participant = BSON("shardId" << ShardId(element.valueStringData().toString()));
                participantArray.emplace_back(participant);
            }
            auto additionalParticipants = BSON("additionalParticipants" << participantArray);

            commandBodyFieldsBob->appendElements(additionalParticipants);
        }
    }
}

class RunCommandOpTimes {
public:
    RunCommandOpTimes(OperationContext* opCtx) : _lastOpBeforeRun(getLastOp(opCtx)) {}

    void onCommandFinished(OperationContext* opCtx) {
        if (!_lastOpAfterRun.isNull()) {
            return;
        }
        _lastOpAfterRun = getLastOp(opCtx);
    }

    const repl::OpTime& getLastOpBeforeRun() const {
        return _lastOpBeforeRun;
    }

    const repl::OpTime& getLastOpAfterRun() const {
        return _lastOpAfterRun;
    }

private:
    repl::OpTime getLastOp(OperationContext* opCtx) {
        return repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
    }

    repl::OpTime _lastOpBeforeRun;
    repl::OpTime _lastOpAfterRun;
};

class ExecCommandDatabase {
public:
    explicit ExecCommandDatabase(std::shared_ptr<HandleRequest::ExecutionContext> execContext)
        : _execContext(std::move(execContext)) {
        _parseCommand();
    }

    // Returns a future that executes a command after stripping metadata, performing authorization
    // checks, handling audit impersonation, and (potentially) setting maintenance mode. The future
    // also checks that the command is permissible to run on the node given its current replication
    // state. All the logic here is independent of any particular command; any functionality
    // relevant to a specific command should be confined to its run() method.
    Future<void> run() {
        return makeReadyFutureWith([&] {
                   _initiateCommand();
                   return _commandExec();
               })
            .onCompletion([this](Status status) {
                // Ensure the lifetime of `_scopedMetrics` ends here.
                _scopedMetrics = boost::none;

                if (!_execContext->client().isInDirectClient()) {
                    auto authzSession = AuthorizationSession::get(_execContext->client());
                    authzSession->verifyContract(
                        _execContext->getCommand()->getAuthorizationContract());
                }

                if (status.isOK())
                    return;
                _handleFailure(std::move(status));
            });
    }

    std::shared_ptr<HandleRequest::ExecutionContext> getExecutionContext() {
        return _execContext;
    }
    std::shared_ptr<CommandInvocation> getInvocation() {
        return _invocation;
    }
    const OperationSessionInfoFromClient& getSessionOptions() const {
        return _sessionOptions;
    }
    BSONObjBuilder* getExtraFieldsBuilder() {
        return &_extraFieldsBuilder;
    }
    const LogicalTime& getStartOperationTime() const {
        return _startOperationTime;
    }

    void onCommandFinished() {
        if (!_runCommandOpTimes) {
            return;
        }
        _runCommandOpTimes->onCommandFinished(_execContext->getOpCtx());
    }

    const boost::optional<RunCommandOpTimes>& getRunCommandOpTimes() {
        return _runCommandOpTimes;
    }

    repl::OpTime getLastOpBeforeRun() {
        if (!_runCommandOpTimes) {
            return repl::OpTime{};
        }
        return _runCommandOpTimes->getLastOpBeforeRun();
    }

    repl::OpTime getLastOpAfterRun() {
        if (!_runCommandOpTimes) {
            return repl::OpTime{};
        }
        return _runCommandOpTimes->getLastOpAfterRun();
    }

    bool isHello() const {
        return _execContext->getCommand()->getName() == "hello"_sd ||
            _execContext->getCommand()->getName() == "isMaster"_sd;
    }

private:
    void _parseCommand() {
        auto opCtx = _execContext->getOpCtx();
        auto command = _execContext->getCommand();
        auto& request = _execContext->getRequest();

        const auto apiParamsFromClient = initializeAPIParameters(request.body, command);
        Client* client = opCtx->getClient();

        {
            stdx::lock_guard<Client> lk(*client);
            CurOp::get(opCtx)->setCommand_inlock(command);
            APIParameters::get(opCtx) = APIParameters::fromClient(apiParamsFromClient);
        }

        CommandHelpers::uassertShouldAttemptParse(opCtx, command, request);
        _startOperationTime = getClientOperationTime(opCtx);

        rpc::readRequestMetadata(opCtx, request, command->requiresAuth());
        _invocation = command->parse(opCtx, request);
        CommandInvocation::set(opCtx, _invocation);

        const auto session = _execContext->getOpCtx()->getClient()->session();
        if (session) {
            if (!opCtx->isExhaust() || !isHello()) {
                InExhaustHello::get(session.get())->setInExhaust(false, request.getCommandName());
            }
        }
    }

    // Do any initialization of the lock state required for a transaction.
    void _setLockStateForTransaction(OperationContext* opCtx) {
        opCtx->lockState()->setSharedLocksShouldTwoPhaseLock(true);
        opCtx->lockState()->setShouldConflictWithSecondaryBatchApplication(false);
    }

    // Clear any lock state which may have changed after the locker update.
    void _resetLockerStateAfterShardingUpdate(OperationContext* opCtx) {
        dassert(!opCtx->isContinuingMultiDocumentTransaction());
        _execContext->behaviors->resetLockerState(opCtx);
        if (opCtx->isStartingMultiDocumentTransaction())
            _setLockStateForTransaction(opCtx);
    }

    // Any logic, such as authorization and auditing, that must precede execution of the command.
    void _initiateCommand();

    // Returns the future chain that executes the parsed command against the database.
    Future<void> _commandExec();

    // Any error-handling logic that must be performed if the command initiation/execution fails.
    void _handleFailure(Status status);

    bool _isInternalClient() const {
        return _execContext->isInternalClient();
    }

    const std::shared_ptr<HandleRequest::ExecutionContext> _execContext;

    // The following allows `_initiateCommand`, `_commandExec`, and `_handleFailure` to share
    // execution state without concerning the lifetime of these variables.
    BSONObjBuilder _extraFieldsBuilder;
    std::shared_ptr<CommandInvocation> _invocation;
    LogicalTime _startOperationTime;
    OperationSessionInfoFromClient _sessionOptions;
    boost::optional<RunCommandOpTimes> _runCommandOpTimes;
    boost::optional<ResourceConsumption::ScopedMetricsCollector> _scopedMetrics;
    boost::optional<ImpersonationSessionGuard> _impersonationSessionGuard;
    boost::optional<auth::SecurityTokenAuthenticationGuard> _tokenAuthorizationSessionGuard;
    std::unique_ptr<PolymorphicScoped> _scoped;
    bool _refreshedDatabase = false;
    bool _refreshedCollection = false;
    bool _refreshedCatalogCache = false;
    // Keep a static variable to track the last time a warning about direct shard connections was
    // logged.
    static Mutex _staticMutex;
    static Date_t _lastDirectConnectionWarningTime;
};

class RunCommandImpl {
public:
    explicit RunCommandImpl(ExecCommandDatabase* ecd) : _ecd(ecd) {}
    virtual ~RunCommandImpl() = default;

    Future<void> run() {
        return makeReadyFutureWith([&] {
                   _prologue();
                   return _runImpl();
               })
            .then([this] { return _epilogue(); })
            .onCompletion([this](Status status) {
                // Failure to run a command is either indicated by throwing an exception or
                // adding a non-okay field to the replyBuilder.
                if (status.isOK() && _ok)
                    return Status::OK();

                auto execContext = _ecd->getExecutionContext();
                execContext->getCommand()->incrementCommandsFailed();
                if (status.code() == ErrorCodes::Unauthorized) {
                    CommandHelpers::auditLogAuthEvent(execContext->getOpCtx(),
                                                      _ecd->getInvocation().get(),
                                                      execContext->getRequest(),
                                                      status.code());
                }

                return status;
            });
    }

protected:
    // Reference to attributes defined in `ExecCommandDatabase` (e.g., sessionOptions).
    ExecCommandDatabase* const _ecd;

    // Any code that must run before command execution (e.g., reserving bytes for reply builder).
    void _prologue();

    // Runs the command possibly waiting for write concern.
    virtual Future<void> _runImpl();

    // Runs the command without waiting for write concern.
    Future<void> _runCommand();

    // Any code that must run after command execution.
    void _epilogue();

    bool _isInternalClient() const {
        return _ecd->getExecutionContext()->isInternalClient();
    }

    // If the command resolved successfully.
    bool _ok = false;
};

class RunCommandAndWaitForWriteConcern final : public RunCommandImpl {
public:
    explicit RunCommandAndWaitForWriteConcern(ExecCommandDatabase* ecd)
        : RunCommandImpl(ecd),
          _execContext(_ecd->getExecutionContext()),
          _oldWriteConcern(_execContext->getOpCtx()->getWriteConcern()) {}

    ~RunCommandAndWaitForWriteConcern() override {
        _execContext->getOpCtx()->setWriteConcern(_oldWriteConcern);
    }

    Future<void> _runImpl() override;

private:
    void _setup();
    Future<void> _runCommandWithFailPoint();
    void _waitForWriteConcern(BSONObjBuilder& bb);
    Future<void> _handleError(Status status);
    Future<void> _checkWriteConcern();

    const std::shared_ptr<HandleRequest::ExecutionContext> _execContext;

    // Allows changing the write concern while running the command and resetting on destruction.
    const WriteConcernOptions _oldWriteConcern;
    boost::optional<WriteConcernOptions> _extractedWriteConcern;
};

// Simplifies the interface for invoking commands and allows asynchronous execution of command
// invocations.
class InvokeCommand {
public:
    explicit InvokeCommand(ExecCommandDatabase* ecd) : _ecd(ecd) {}

    Future<void> run();

private:
    ExecCommandDatabase* const _ecd;
};

class CheckoutSessionAndInvokeCommand {
public:
    CheckoutSessionAndInvokeCommand(ExecCommandDatabase* ecd) : _ecd{ecd} {}

    ~CheckoutSessionAndInvokeCommand() {
        auto opCtx = _ecd->getExecutionContext()->getOpCtx();
        if (auto txnParticipant = TransactionParticipant::get(opCtx)) {
            // Only cleanup if we didn't yield the session.
            _cleanupTransaction(txnParticipant);
        }
    }

    Future<void> run();

private:
    void _stashTransaction(TransactionParticipant::Participant& txnParticipant);
    void _cleanupTransaction(TransactionParticipant::Participant& txnParticipant);

    void _checkOutSession();
    void _tapError(Status);
    Future<void> _commitInvocation();

    ExecCommandDatabase* const _ecd;

    std::unique_ptr<MongoDSessionCatalog::Session> _sessionTxnState;
    bool _shouldCleanUp = false;
};

Future<void> InvokeCommand::run() {
    return makeReadyFutureWith([&] {
               auto execContext = _ecd->getExecutionContext();
               const auto dbName = _ecd->getInvocation()->ns().dbName();
               // TODO SERVER-53761: find out if we can do this more asynchronously. The client
               // Strand is locked to current thread in SessionWorkflow::Impl::startNewLoop().
               tenant_migration_access_blocker::checkIfCanReadOrBlock(
                   execContext->getOpCtx(), dbName, execContext->getRequest())
                   .get(execContext->getOpCtx());
               return runCommandInvocation(_ecd->getExecutionContext(), _ecd->getInvocation());
           })
        .onErrorCategory<ErrorCategory::TenantMigrationConflictError>([this](Status status) {
            uassertStatusOK(tenant_migration_access_blocker::handleTenantMigrationConflict(
                _ecd->getExecutionContext()->getOpCtx(), std::move(status)));
            return Status::OK();
        });
}

Future<void> CheckoutSessionAndInvokeCommand::run() {
    return makeReadyFutureWith([&] {
               _checkOutSession();

               auto execContext = _ecd->getExecutionContext();
               const auto dbName = _ecd->getInvocation()->ns().dbName();
               // TODO SERVER-53761: find out if we can do this more asynchronously.
               tenant_migration_access_blocker::checkIfCanReadOrBlock(
                   execContext->getOpCtx(), dbName, execContext->getRequest())
                   .get(execContext->getOpCtx());
               return runCommandInvocation(_ecd->getExecutionContext(), _ecd->getInvocation());
           })
        .onErrorCategory<ErrorCategory::TenantMigrationConflictError>([this](Status status) {
            auto opCtx = _ecd->getExecutionContext()->getOpCtx();
            if (auto txnParticipant = TransactionParticipant::get(opCtx)) {
                // If the command didn't yield its session, abort transaction and clean up
                // transaction resources before blocking the command to allow the stable timestamp
                // on the node to advance.
                _cleanupTransaction(txnParticipant);
            }

            uassertStatusOK(tenant_migration_access_blocker::handleTenantMigrationConflict(
                opCtx, std::move(status)));
        })
        .onError<ErrorCodes::WouldChangeOwningShard>([this](Status status) -> Future<void> {
            auto opCtx = _ecd->getExecutionContext()->getOpCtx();
            auto txnParticipant = TransactionParticipant::get(opCtx);
            if (!txnParticipant) {
                // No code paths that can throw this error should yield their session but uassert
                // instead of invariant in case that assumption is ever broken since this only needs
                // to be operation fatal.
                auto statusWithContext = status.withContext(
                    "Cannot handle WouldChangeOwningShard error because the operation yielded its "
                    "session");
                uasserted(6609000, statusWithContext.reason());
            }

            auto wouldChangeOwningShardInfo = status.extraInfo<WouldChangeOwningShardInfo>();
            invariant(wouldChangeOwningShardInfo);
            txnParticipant.handleWouldChangeOwningShardError(opCtx, wouldChangeOwningShardInfo);
            _stashTransaction(txnParticipant);

            auto txnResponseMetadata = txnParticipant.getResponseMetadata();
            txnResponseMetadata.serialize(_ecd->getExtraFieldsBuilder());
            return status;
        })
        .tapError([this](Status status) { _tapError(status); })
        .then([this] { return _commitInvocation(); });
}

void CheckoutSessionAndInvokeCommand::_stashTransaction(
    TransactionParticipant::Participant& txnParticipant) {
    invariant(txnParticipant);
    if (!_shouldCleanUp) {
        return;
    }
    _shouldCleanUp = false;

    auto opCtx = _ecd->getExecutionContext()->getOpCtx();
    txnParticipant.stashTransactionResources(opCtx);
}

void CheckoutSessionAndInvokeCommand::_cleanupTransaction(
    TransactionParticipant::Participant& txnParticipant) {
    invariant(txnParticipant);
    if (!_shouldCleanUp) {
        return;
    }
    _shouldCleanUp = false;

    auto opCtx = _ecd->getExecutionContext()->getOpCtx();
    const bool isPrepared = txnParticipant.transactionIsPrepared();
    try {
        if (isPrepared)
            txnParticipant.stashTransactionResources(opCtx);
        else if (txnParticipant.transactionIsOpen())
            txnParticipant.abortTransaction(opCtx);
    } catch (...) {
        // It is illegal for this to throw so we catch and log this here for diagnosability.
        LOGV2_FATAL(21974,
                    "Caught exception during transaction {txnNumber} {operation} "
                    "{logicalSessionId}: {error}",
                    "Unable to stash/abort transaction",
                    "operation"_attr = (isPrepared ? "stash" : "abort"),
                    "txnNumber"_attr = opCtx->getTxnNumber(),
                    "logicalSessionId"_attr = opCtx->getLogicalSessionId()->toBSON(),
                    "error"_attr = exceptionToStatus());
    }
}

void CheckoutSessionAndInvokeCommand::_checkOutSession() {
    auto execContext = _ecd->getExecutionContext();
    auto opCtx = execContext->getOpCtx();
    CommandInvocation* invocation = _ecd->getInvocation().get();
    const OperationSessionInfoFromClient& sessionOptions = _ecd->getSessionOptions();

    // This constructor will check out the session. It handles the appropriate state management
    // for both multi-statement transactions and retryable writes. Currently, only requests with
    // a transaction number will check out the session.
    hangBeforeSessionCheckOut.pauseWhileSet();
    auto mongoDSessionCatalog = MongoDSessionCatalog::get(opCtx);
    _sessionTxnState = mongoDSessionCatalog->checkOutSession(opCtx);
    auto txnParticipant = TransactionParticipant::get(opCtx);
    hangAfterSessionCheckOut.pauseWhileSet();

    // Used for waiting for an in-progress transaction to transition out of the conflicting state.
    auto waitForInProgressTxn = [this](OperationContext* opCtx, auto& stateTransitionFuture) {
        // Check the session back in and wait for the conflict to resolve.
        _sessionTxnState->checkIn(opCtx, OperationContextSession::CheckInReason::kYield);
        stateTransitionFuture.wait(opCtx);
        // Wait for any commit or abort oplog entry to be visible in the oplog. This will prevent a
        // new transaction from missing the transaction table update for the previous commit or
        // abort due to an oplog hole.
        auto storageInterface = repl::StorageInterface::get(opCtx);
        storageInterface->waitForAllEarlierOplogWritesToBeVisible(opCtx);
        // Check out the session again.
        _sessionTxnState->checkOut(opCtx);
    };

    auto apiParamsFromClient = APIParameters::get(opCtx);
    auto apiParamsFromTxn = txnParticipant.getAPIParameters(opCtx);
    uassert(
        ErrorCodes::APIMismatchError,
        "API parameter mismatch: {} used params {}, the transaction's first command used {}"_format(
            invocation->definition()->getName(),
            apiParamsFromClient.toBSON().toString(),
            apiParamsFromTxn.toBSON().toString()),
        apiParamsFromTxn == apiParamsFromClient);

    if (!opCtx->getClient()->isInDirectClient()) {
        bool beganOrContinuedTxn{false};
        // This loop allows new transactions on a session to block behind a previous prepared
        // transaction on that session.
        while (!beganOrContinuedTxn) {
            try {
                auto opObserver = opCtx->getServiceContext()->getOpObserver();
                opObserver->onTransactionStart(opCtx);
                txnParticipant.beginOrContinue(
                    opCtx,
                    {*sessionOptions.getTxnNumber(), sessionOptions.getTxnRetryCounter()},
                    sessionOptions.getAutocommit(),
                    sessionOptions.getStartTransaction());
                beganOrContinuedTxn = true;
            } catch (const ExceptionFor<ErrorCodes::PreparedTransactionInProgress>&) {
                auto prevTxnExitedPrepare = txnParticipant.onExitPrepare();

                CurOpFailpointHelpers::waitWhileFailPointEnabled(
                    &waitAfterNewStatementBlocksBehindPrepare,
                    opCtx,
                    "waitAfterNewStatementBlocksBehindPrepare");

                waitForInProgressTxn(opCtx, prevTxnExitedPrepare);
            } catch (const ExceptionFor<ErrorCodes::RetryableTransactionInProgress>&) {
                auto conflictingTxnCommittedOrAborted =
                    txnParticipant.onConflictingInternalTransactionCompletion(opCtx);

                waitAfterNewStatementBlocksBehindOpenInternalTransactionForRetryableWrite
                    .pauseWhileSet();

                waitForInProgressTxn(opCtx, conflictingTxnCommittedOrAborted);
            }
        }

        // Create coordinator if needed. If "startTransaction" is present, it must be true.
        if (sessionOptions.getStartTransaction()) {
            // If this shard has been selected as the coordinator, set up the coordinator state
            // to be ready to receive votes.
            if (sessionOptions.getCoordinator() == boost::optional<bool>(true)) {
                createTransactionCoordinator(
                    opCtx, *sessionOptions.getTxnNumber(), sessionOptions.getTxnRetryCounter());
            }
        }

        // Release the transaction lock resources and abort storage transaction for unprepared
        // transactions on failure to unstash the transaction resources to opCtx. We don't want to
        // have this error guard for beginOrContinue as it can abort the transaction for any
        // accidental invalid statements in the transaction.
        //
        // Unstashing resources can't yield the session so it's safe to capture a reference to the
        // TransactionParticipant in this scope guard.
        ScopeGuard abortOnError([&] {
            if (txnParticipant.transactionIsInProgress()) {
                txnParticipant.abortTransaction(opCtx);
            }
        });

        txnParticipant.unstashTransactionResources(opCtx, invocation->definition()->getName());

        // Unstash success.
        abortOnError.dismiss();
    }

    _shouldCleanUp = true;

    if (!opCtx->getClient()->isInDirectClient()) {
        const auto& readConcernArgs = repl::ReadConcernArgs::get(opCtx);

        auto command = invocation->definition();
        // Record readConcern usages for commands run inside transactions after unstashing the
        // transaction resources.
        if (command->shouldAffectReadConcernCounter() && opCtx->inMultiDocumentTransaction()) {
            ServerReadConcernMetrics::get(opCtx)->recordReadConcern(readConcernArgs,
                                                                    true /* isTransaction */);
        }

        // For replica sets, we do not receive the readConcernArgs of our parent transaction
        // statements until we unstash the transaction resources. The below check is necessary to
        // ensure commands, including those occurring after the first statement in their respective
        // transactions, are checked for readConcern support. Presently, only `create` and
        // `createIndexes` do not support readConcern inside transactions.
        // TODO(SERVER-46971): Consider how to extend this check to other commands.
        auto cmdName = command->getName();
        auto readConcernSupport = invocation->supportsReadConcern(
            readConcernArgs.getLevel(), readConcernArgs.isImplicitDefault());
        if (readConcernArgs.hasLevel() &&
            (cmdName == "create"_sd || cmdName == "createIndexes"_sd)) {
            if (!readConcernSupport.readConcernSupport.isOK()) {
                uassertStatusOK(readConcernSupport.readConcernSupport.withContext(
                    "Command {} does not support this transaction's {}"_format(
                        cmdName, readConcernArgs.toString())));
            }
        }
    }
}

void CheckoutSessionAndInvokeCommand::_tapError(Status status) {
    const OperationSessionInfoFromClient& sessionOptions = _ecd->getSessionOptions();
    if (status.code() == ErrorCodes::CommandOnShardedViewNotSupportedOnMongod) {
        // Exceptions are used to resolve views in a sharded cluster, so they should be handled
        // specially to avoid unnecessary aborts.

        // If "startTransaction" is present, it must be true.
        if (sessionOptions.getStartTransaction()) {
            // If the first command a shard receives in a transactions fails with this code, the
            // shard may not be included in the final participant list if the router's retry after
            // resolving the view does not re-target it, which is possible if the underlying
            // collection is sharded. The shard's transaction should be preemptively aborted to
            // avoid leaving it orphaned in this case, which is fine even if it is re-targeted
            // because the retry will include "startTransaction" again and "restart" a transaction
            // at the active txnNumber.
            return;
        }

        auto opCtx = _ecd->getExecutionContext()->getOpCtx();
        auto txnParticipant = TransactionParticipant::get(opCtx);
        if (!txnParticipant) {
            // No code paths that can throw this error should yield their session but uassert
            // instead of invariant in case that assumption is ever broken since this only needs to
            // be operation fatal.
            auto statusWithContext = status.withContext(
                "Cannot handle CommandOnShardedViewNotSupportedOnMongod error because the "
                "operation yielded its session");
            uasserted(6609001, statusWithContext.reason());
        }

        // If this shard has completed an earlier statement for this transaction, it must already be
        // in the transaction's participant list, so it is guaranteed to learn its outcome.
        _stashTransaction(txnParticipant);
    }
}

Future<void> CheckoutSessionAndInvokeCommand::_commitInvocation() {
    auto execContext = _ecd->getExecutionContext();
    auto replyBuilder = execContext->getReplyBuilder();
    if (auto okField = replyBuilder->getBodyBuilder().asTempObj()["ok"]) {
        // If ok is present, use its truthiness.
        if (!okField.trueValue()) {
            return Status::OK();
        }
    }

    if (auto txnParticipant = TransactionParticipant::get(execContext->getOpCtx())) {
        // If the command didn't yield its session, stash or commit the transaction when the command
        // succeeds.
        _stashTransaction(txnParticipant);

        if (serverGlobalParams.clusterRole.has(ClusterRole::ShardServer) ||
            serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer)) {
            auto txnResponseMetadata = txnParticipant.getResponseMetadata();
            auto bodyBuilder = replyBuilder->getBodyBuilder();
            txnResponseMetadata.serialize(&bodyBuilder);
        }
    }

    return Status::OK();
}

void RunCommandImpl::_prologue() {
    auto execContext = _ecd->getExecutionContext();
    auto opCtx = execContext->getOpCtx();
    const Command* command = _ecd->getInvocation()->definition();
    auto bytesToReserve = command->reserveBytesForReply();
// SERVER-22100: In Windows DEBUG builds, the CRT heap debugging overhead, in conjunction with the
// additional memory pressure introduced by reply buffer pre-allocation, causes the concurrency
// suite to run extremely slowly. As a workaround we do not pre-allocate in Windows DEBUG builds.
#ifdef _WIN32
    if (kDebugBuild)
        bytesToReserve = 0;
#endif
    execContext->getReplyBuilder()->reserveBytes(bytesToReserve);

    // Record readConcern usages for commands run outside of transactions, excluding DBDirectClient.
    // For commands inside a transaction, they inherit the readConcern from the transaction. So we
    // will record their readConcern usages after we have unstashed the transaction resources.
    if (!opCtx->getClient()->isInDirectClient() && command->shouldAffectReadConcernCounter() &&
        !opCtx->inMultiDocumentTransaction()) {
        ServerReadConcernMetrics::get(opCtx)->recordReadConcern(repl::ReadConcernArgs::get(opCtx),
                                                                false /* isTransaction */);
    }
}

void RunCommandImpl::_epilogue() {
    auto execContext = _ecd->getExecutionContext();
    auto opCtx = execContext->getOpCtx();
    auto& request = execContext->getRequest();
    auto command = execContext->getCommand();
    auto replyBuilder = execContext->getReplyBuilder();
    auto& behaviors = *execContext->behaviors;
    _ecd->onCommandFinished();

    // This fail point blocks all commands which are running on the specified namespace, or which
    // are present in the given list of commands, or which match a given comment. If no namespace,
    // command list, or comment are provided, then the failpoint will block all commands.
    waitAfterCommandFinishesExecution.executeIf(
        [&](const BSONObj& data) {
            CurOpFailpointHelpers::waitWhileFailPointEnabled(
                &waitAfterCommandFinishesExecution, opCtx, "waitAfterCommandFinishesExecution");
        },
        [&](const BSONObj& data) {
            auto ns = data["ns"].valueStringDataSafe();
            auto commands =
                data.hasField("commands") ? data["commands"].Array() : std::vector<BSONElement>();
            bool requestMatchesComment = data.hasField("comment")
                ? data.getField("comment").woCompare(request.body.getField("comment")) == 0
                : true;

            // If 'ns', 'commands', or 'comment' is not set, block for all the namespaces, commands,
            // or comments respectively.
            return (ns.empty() || _ecd->getInvocation()->ns().ns() == ns) &&
                (commands.empty() ||
                 std::any_of(commands.begin(),
                             commands.end(),
                             [&request](auto& element) {
                                 return element.valueStringDataSafe() == request.getCommandName();
                             })) &&
                requestMatchesComment;
        });

    behaviors.waitForLinearizableReadConcern(opCtx);
    const DatabaseName requestDbName =
        DatabaseNameUtil::deserialize(request.getValidatedTenantId(), request.getDatabase());
    tenant_migration_access_blocker::checkIfLinearizableReadWasAllowedOrThrow(opCtx, requestDbName);

    // Wait for data to satisfy the read concern level, if necessary.
    behaviors.waitForSpeculativeMajorityReadConcern(opCtx);

    {
        auto body = replyBuilder->getBodyBuilder();
        _ok = CommandHelpers::extractOrAppendOk(body);
    }
    behaviors.attachCurOpErrInfo(opCtx, replyBuilder->getBodyBuilder().asTempObj());

    {
        boost::optional<ErrorCodes::Error> code;
        boost::optional<ErrorCodes::Error> wcCode;
        auto body = replyBuilder->getBodyBuilder();
        auto response = body.asTempObj();
        auto codeField = response["code"];
        if (!_ok && codeField.isNumber()) {
            code = ErrorCodes::Error(codeField.numberInt());
        }
        if (response.hasField("writeConcernError")) {
            wcCode = ErrorCodes::Error(response["writeConcernError"]["code"].numberInt());
        }
        appendErrorLabelsAndTopologyVersion(opCtx,
                                            &body,
                                            _ecd->getSessionOptions(),
                                            command->getName(),
                                            code,
                                            wcCode,
                                            _isInternalClient(),
                                            _ecd->getLastOpBeforeRun(),
                                            _ecd->getLastOpAfterRun());
        appendAdditionalParticipants(
            opCtx, &body, command->getName(), _ecd->getInvocation()->ns().ns());
    }

    auto commandBodyBob = replyBuilder->getBodyBuilder();
    behaviors.appendReplyMetadata(opCtx, request, &commandBodyBob);
    appendClusterAndOperationTime(
        opCtx, &commandBodyBob, &commandBodyBob, _ecd->getStartOperationTime());
}

Future<void> RunCommandImpl::_runImpl() {
    auto execContext = _ecd->getExecutionContext();
    execContext->behaviors->uassertCommandDoesNotSpecifyWriteConcern(
        execContext->getRequest().body);
    return _runCommand();
}

Future<void> RunCommandImpl::_runCommand() {
    auto shouldCheckoutSession = _ecd->getSessionOptions().getTxnNumber() &&
        _ecd->getInvocation()->definition()->shouldCheckoutSession();
    if (shouldCheckoutSession) {
        return future_util::makeState<CheckoutSessionAndInvokeCommand>(_ecd).thenWithState(
            [](auto* path) { return path->run(); });
    } else {
        return future_util::makeState<InvokeCommand>(_ecd).thenWithState(
            [](auto* path) { return path->run(); });
    }
}

void RunCommandAndWaitForWriteConcern::_waitForWriteConcern(BSONObjBuilder& bb) {
    auto invocation = _ecd->getInvocation().get();
    auto opCtx = _execContext->getOpCtx();
    if (auto scoped = failCommand.scopedIf([&](const BSONObj& obj) {
            return CommandHelpers::shouldActivateFailCommandFailPoint(
                       obj, invocation, opCtx->getClient()) &&
                obj.hasField("writeConcernError");
        });
        MONGO_unlikely(scoped.isActive())) {
        const BSONObj& data = scoped.getData();
        bb.append(data["writeConcernError"]);
        if (data.hasField(kErrorLabelsFieldName) && data[kErrorLabelsFieldName].type() == Array) {
            // Propagate error labels specified in the failCommand failpoint to the
            // OperationContext decoration to override getErrorLabels() behaviors.
            invariant(!errorLabelsOverride(opCtx));
            errorLabelsOverride(opCtx).emplace(
                data.getObjectField(kErrorLabelsFieldName).getOwned());
        }
        return;
    }

    CurOp::get(opCtx)->debug().writeConcern.emplace(opCtx->getWriteConcern());
    _execContext->behaviors->waitForWriteConcern(opCtx, invocation, _ecd->getLastOpBeforeRun(), bb);
}

Future<void> RunCommandAndWaitForWriteConcern::_runImpl() {
    _setup();
    return _runCommandWithFailPoint().onCompletion([this](Status status) mutable {
        _ecd->onCommandFinished();
        if (status.isOK()) {
            return _checkWriteConcern();
        } else {
            return _handleError(std::move(status));
        }
    });
}

void RunCommandAndWaitForWriteConcern::_setup() {
    auto invocation = _ecd->getInvocation();
    OperationContext* opCtx = _execContext->getOpCtx();
    const Command* command = invocation->definition();
    const OpMsgRequest& request = _execContext->getRequest();

    if (command->getLogicalOp() == LogicalOp::opGetMore) {
        // WriteConcern will be set up during command processing, it must not be specified on
        // the command body.
        _execContext->behaviors->uassertCommandDoesNotSpecifyWriteConcern(request.body);
    } else {
        // WriteConcern should always be explicitly specified by operations received on shard
        // and config servers, even if it is empty (ie. writeConcern: {}).  In this context
        // (shard/config servers) an empty WC indicates the operation should use the implicit
        // server defaults.  So, warn if the operation has not specified writeConcern and is on
        // a shard/config server.
        if (!opCtx->getClient()->isInDirectClient() &&
            (!opCtx->inMultiDocumentTransaction() || command->isTransactionCommand())) {
            if (_isInternalClient()) {
                // WriteConcern should always be explicitly specified by operations received
                // from internal clients (ie. from a mongos or mongod), even if it is empty
                // (ie. writeConcern: {}, which is equivalent to { w: 1, wtimeout: 0 }).
                uassert(
                    4569201,
                    "received command without explicit writeConcern on an internalClient connection {}"_format(
                        redact(request.body.toString())),
                    request.body.hasField(WriteConcernOptions::kWriteConcernField));
            } else if (serverGlobalParams.clusterRole.has(ClusterRole::ShardServer) ||
                       serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer)) {
                if (!request.body.hasField(WriteConcernOptions::kWriteConcernField)) {
                    // TODO: Disabled until after SERVER-44539, to avoid log spam.
                    // LOGV2(21959, "Missing writeConcern on {command}", "Missing "
                    // "writeConcern on command", "command"_attr = command->getName());
                }
            }
        }
        _extractedWriteConcern.emplace(
            uassertStatusOK(extractWriteConcern(opCtx, request.body, _isInternalClient())));
        if (_ecd->getSessionOptions().getAutocommit()) {
            validateWriteConcernForTransaction(*_extractedWriteConcern,
                                               invocation->definition()->getName());
        }

        // Ensure that the WC being set on the opCtx has provenance.
        invariant(_extractedWriteConcern->getProvenance().hasSource(),
                  fmt::format("unexpected unset provenance on writeConcern: {}",
                              _extractedWriteConcern->toBSON().jsonString()));

        opCtx->setWriteConcern(*_extractedWriteConcern);
    }
}

Future<void> RunCommandAndWaitForWriteConcern::_runCommandWithFailPoint() {
    // TODO SERVER-69061 rename `failWithErrorCodeInRunCommand` and remove the following comment.
    // Despite the name, this failpoint only affects commands with write concerns.
    if (auto scoped = failWithErrorCodeInRunCommand.scoped(); MONGO_unlikely(scoped.isActive())) {
        const auto errorCode = scoped.getData()["errorCode"].numberInt();
        LOGV2(21960,
              "failWithErrorCodeInRunCommand enabled - failing command with error "
              "code: {errorCode}",
              "failWithErrorCodeInRunCommand enabled, failing command",
              "errorCode"_attr = errorCode);
        BSONObjBuilder errorBuilder;
        errorBuilder.append("ok", 0.0);
        errorBuilder.append("code", errorCode);
        errorBuilder.append("errmsg", "failWithErrorCodeInRunCommand enabled.");
        _ecd->getExecutionContext()->getReplyBuilder()->setCommandReply(errorBuilder.obj());
        return Status::OK();
    }

    return RunCommandImpl::_runCommand();
}

Future<void> RunCommandAndWaitForWriteConcern::_handleError(Status status) {
    auto opCtx = _execContext->getOpCtx();
    // Do no-op write before returning NoSuchTransaction if command has writeConcern.
    if (status.code() == ErrorCodes::NoSuchTransaction &&
        !opCtx->getWriteConcern().usedDefaultConstructedWC) {
        TransactionParticipant::performNoopWrite(opCtx, "NoSuchTransaction error");
    }
    _waitForWriteConcern(*_ecd->getExtraFieldsBuilder());
    return status;
}

Future<void> RunCommandAndWaitForWriteConcern::_checkWriteConcern() {
    auto opCtx = _execContext->getOpCtx();
    auto bb = _execContext->getReplyBuilder()->getBodyBuilder();
    _waitForWriteConcern(bb);

    // With the exception of getMores inheriting the WriteConcern from the originating command,
    // nothing in run() should change the writeConcern.
    if (_execContext->getCommand()->getLogicalOp() == LogicalOp::opGetMore) {
        dassert(!_extractedWriteConcern, "opGetMore contained unexpected extracted write concern");
    } else {
        dassert(_extractedWriteConcern, "no extracted write concern");
        dassert(
            opCtx->getWriteConcern() == _extractedWriteConcern,
            "opCtx wc: {} extracted wc: {}"_format(opCtx->getWriteConcern().toBSON().jsonString(),
                                                   _extractedWriteConcern->toBSON().jsonString()));
    }
    return Status::OK();
}

Mutex ExecCommandDatabase::_staticMutex = MONGO_MAKE_LATCH("DirectShardConnectionTimer");
Date_t ExecCommandDatabase::_lastDirectConnectionWarningTime = Date_t();

void ExecCommandDatabase::_initiateCommand() {
    auto opCtx = _execContext->getOpCtx();
    auto& request = _execContext->getRequest();
    auto command = _execContext->getCommand();
    auto replyBuilder = _execContext->getReplyBuilder();

    // Record the time here to ensure that maxTimeMS, if set by the command, considers the time
    // spent before the deadline is set on `opCtx`.
    const auto startedCommandExecAt = opCtx->getServiceContext()->getFastClockSource()->now();

    Client* client = opCtx->getClient();

    if (auto scope = request.validatedTenancyScope; scope && scope->hasAuthenticatedUser()) {
        uassert(ErrorCodes::Unauthorized,
                str::stream() << "Command " << command->getName()
                              << " is not supported in multitenancy mode",
                command->allowedWithSecurityToken());
        _tokenAuthorizationSessionGuard.emplace(opCtx, request.validatedTenancyScope.value());
    }

    if (MONGO_unlikely(isHello())) {
        // Preload generic ClientMetadata ahead of our first hello request. After the first
        // request, metaElement should always be empty.
        auto metaElem = request.body[kMetadataDocumentName];
        auto isInternalClient = request.body["internalClient"_sd].ok();
        ClientMetadata::setFromMetadata(opCtx->getClient(), metaElem, isInternalClient);
    }

    if (auto clientMetadata = ClientMetadata::get(client)) {
        auto& apiParams = APIParameters::get(opCtx);
        auto& apiVersionMetrics = APIVersionMetrics::get(opCtx->getServiceContext());
        auto appName = clientMetadata->getApplicationName().toString();
        apiVersionMetrics.update(appName, apiParams);
    }

    rpc::TrackingMetadata::get(opCtx).initWithOperName(command->getName());

    auto const replCoord = repl::ReplicationCoordinator::get(opCtx);

    _sessionOptions = initializeOperationSessionInfo(opCtx,
                                                     request.body,
                                                     command->requiresAuth(),
                                                     command->attachLogicalSessionsToOpCtx(),
                                                     replCoord->getReplicationMode() ==
                                                         repl::ReplicationCoordinator::modeReplSet);

    // Start authz contract tracking before we evaluate failpoints
    auto authzSession = AuthorizationSession::get(client);
    authzSession->startContractTracking();

    CommandHelpers::evaluateFailCommandFailPoint(opCtx, _invocation.get());

    const auto dbname = request.getDatabase().toString();
    uassert(ErrorCodes::InvalidNamespace,
            fmt::format("Invalid database name: '{}'", dbname),
            NamespaceString::validDBName(dbname, NamespaceString::DollarInDbNameBehavior::Allow));

    // Connections from mongod or mongos clients (i.e. initial sync, mirrored reads, etc.) should
    // not contribute to resource consumption metrics.
    const bool collect = command->collectsResourceConsumptionMetrics() && !_isInternalClient();
    _scopedMetrics.emplace(
        opCtx,
        DatabaseNameUtil::deserialize(request.getValidatedTenantId(), request.getDatabase()),
        collect);

    const auto allowTransactionsOnConfigDatabase =
        (serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer) ||
         serverGlobalParams.clusterRole.has(ClusterRole::ShardServer)) ||
        client->isFromSystemConnection();

    const auto invocationNss = _invocation->ns();

    validateSessionOptions(
        _sessionOptions, command->getName(), invocationNss, allowTransactionsOnConfigDatabase);

    BSONElement cmdOptionMaxTimeMSField;
    BSONElement maxTimeMSOpOnlyField;
    BSONElement helpField;

    StringDataSet topLevelFields(8);
    for (auto&& element : request.body) {
        StringData fieldName = element.fieldNameStringData();
        if (fieldName == query_request_helper::cmdOptionMaxTimeMS) {
            cmdOptionMaxTimeMSField = element;
        } else if (fieldName == query_request_helper::kMaxTimeMSOpOnlyField) {
            uassert(ErrorCodes::InvalidOptions,
                    "Can not specify maxTimeMSOpOnly for non internal clients",
                    _isInternalClient());
            maxTimeMSOpOnlyField = element;
        } else if (fieldName == CommandHelpers::kHelpFieldName) {
            helpField = element;
        } else if (fieldName == "comment") {
            stdx::lock_guard<Client> lk(*client);
            opCtx->setComment(element.wrap());
        } else if (fieldName == query_request_helper::queryOptionMaxTimeMS) {
            uasserted(ErrorCodes::InvalidOptions,
                      "no such command option $maxTimeMs; use maxTimeMS instead");
        }

        uassert(ErrorCodes::FailedToParse,
                str::stream() << "Parsed command object contains duplicate top level key: "
                              << fieldName,
                topLevelFields.insert(fieldName).second);
    }

    if (MONGO_unlikely(CommandHelpers::isHelpRequest(helpField))) {
        CurOp::get(opCtx)->ensureStarted();
        // We disable not-primary-error tracker for help requests due to SERVER-11492, because
        // config servers use help requests to determine which commands are database writes, and so
        // must be forwarded to all config servers.
        NotPrimaryErrorTracker::get(opCtx->getClient()).disable();
        Command::generateHelpResponse(opCtx, replyBuilder, *command);
        iassert(Status(ErrorCodes::SkipCommandExecution,
                       "Skipping command execution for help request"));
    }

    _impersonationSessionGuard.emplace(opCtx);

    // Restart contract tracking afer the impersonation guard checks for impersonate if using
    // impersonation.
    if (_impersonationSessionGuard->isActive()) {
        authzSession->startContractTracking();
    }

    _invocation->checkAuthorization(opCtx, request);
    const auto dbName =
        DatabaseNameUtil::deserialize(request.getValidatedTenantId(), request.getDatabase());
    const bool iAmPrimary = replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbName);

    if (!opCtx->getClient()->isInDirectClient() &&
        !MONGO_unlikely(skipCheckingForNotPrimaryInCommandDispatch.shouldFail())) {
        const bool inMultiDocumentTransaction = (_sessionOptions.getAutocommit() == false);

        // Kill this operation on step down even if it hasn't taken write locks yet, because it
        // could conflict with transactions from a new primary.
        if (inMultiDocumentTransaction) {
            hangBeforeSettingTxnInterruptFlag.pauseWhileSet();
            opCtx->setAlwaysInterruptAtStepDownOrUp_UNSAFE();
        }

        auto allowed = command->secondaryAllowed(opCtx->getServiceContext());
        bool alwaysAllowed = allowed == Command::AllowedOnSecondary::kAlways;
        bool couldHaveOptedIn =
            allowed == Command::AllowedOnSecondary::kOptIn && !inMultiDocumentTransaction;
        bool optedIn = couldHaveOptedIn && ReadPreferenceSetting::get(opCtx).canRunOnSecondary();
        bool canRunHere = commandCanRunHere(opCtx, dbName, command, inMultiDocumentTransaction);
        if (!canRunHere && couldHaveOptedIn) {
            const auto msg = client->supportsHello() ? "not primary and secondaryOk=false"_sd
                                                     : "not master and slaveOk=false"_sd;
            uasserted(ErrorCodes::NotPrimaryNoSecondaryOk, msg);
        }

        if (MONGO_unlikely(respondWithNotPrimaryInCommandDispatch.shouldFail())) {
            uassert(ErrorCodes::NotWritablePrimary, "not primary", canRunHere);
        } else {
            const auto msg = client->supportsHello() ? "not primary"_sd : "not master"_sd;
            uassert(ErrorCodes::NotWritablePrimary, msg, canRunHere);
        }

        if (!command->maintenanceOk() &&
            replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet &&
            !replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbName) &&
            !replCoord->getMemberState().secondary()) {

            uassert(ErrorCodes::NotPrimaryOrSecondary,
                    "node is recovering",
                    !replCoord->getMemberState().recovering());
            uassert(ErrorCodes::NotPrimaryOrSecondary,
                    "node is not in primary or recovering state",
                    replCoord->getMemberState().primary());
            // Check ticket SERVER-21432, slaveOk commands are allowed in drain mode
            uassert(ErrorCodes::NotPrimaryOrSecondary,
                    "node is in drain mode",
                    optedIn || alwaysAllowed);
        }

        // We acquire the RSTL which helps us here in two ways:
        // 1) It forces us to wait out any outstanding stepdown attempts.
        // 2) It guarantees that future RSTL holders will see the
        // 'setAlwaysInterruptAtStepDownOrUp_UNSAFE' flag we set above.
        if (inMultiDocumentTransaction) {
            hangAfterCheckingWritabilityForMultiDocumentTransactions.pauseWhileSet();
            repl::ReplicationStateTransitionLockGuard rstl(opCtx, MODE_IX);
            uassert(ErrorCodes::NotWritablePrimary,
                    "Cannot start a transaction in a non-primary state",
                    replCoord->canAcceptWritesForDatabase(opCtx, dbName));
        }
    }

    if (command->adminOnly()) {
        LOGV2_DEBUG(21961,
                    2,
                    "Admin only command: {command}",
                    "Admin only command",
                    "command"_attr = request.getCommandName());
    }

    if (command->shouldAffectCommandCounter()) {
        globalOpCounters.gotCommand();
        if (analyze_shard_key::supportsSamplingQueries(opCtx)) {
            analyze_shard_key::QueryAnalysisSampler::get(opCtx).gotCommand(
                request.getCommandName());
        }
    }

    if (cmdOptionMaxTimeMSField || maxTimeMSOpOnlyField) {
        // Parse the 'maxTimeMS' command option, and use it to set a deadline for the operation on
        // the OperationContext. The 'maxTimeMS' option unfortunately has a different meaning for a
        // getMore command, where it is used to communicate the maximum time to wait for new inserts
        // on tailable cursors, not as a deadline for the operation.
        //
        // TODO SERVER-34277 Remove the special handling for maxTimeMS for getMores. This will
        // require introducing a new 'max await time' parameter for getMore, and eventually banning
        // maxTimeMS altogether on a getMore command.
        const auto maxTimeMS =
            Milliseconds{uassertStatusOK(parseMaxTimeMS(cmdOptionMaxTimeMSField))};
        const auto maxTimeMSOpOnly =
            Milliseconds{uassertStatusOK(parseMaxTimeMS(maxTimeMSOpOnlyField))};

        if ((maxTimeMS > Milliseconds::zero() || maxTimeMSOpOnly > Milliseconds::zero()) &&
            command->getLogicalOp() != LogicalOp::opGetMore) {
            uassert(40119,
                    "Illegal attempt to set operation deadline within DBDirectClient",
                    !opCtx->getClient()->isInDirectClient());

            // The "hello" command should not inherit the deadline from the user op it is operating
            // as a part of as that can interfere with replica set monitoring and host selection.
            const bool ignoreMaxTimeMSOpOnly = isHello();

            if (!ignoreMaxTimeMSOpOnly && maxTimeMSOpOnly > Milliseconds::zero() &&
                (maxTimeMS == Milliseconds::zero() || maxTimeMSOpOnly < maxTimeMS)) {
                opCtx->storeMaxTimeMS(maxTimeMS);
                opCtx->setDeadlineByDate(startedCommandExecAt + maxTimeMSOpOnly,
                                         ErrorCodes::MaxTimeMSExpired);
            } else if (maxTimeMS > Milliseconds::zero()) {
                opCtx->setDeadlineByDate(startedCommandExecAt + maxTimeMS,
                                         ErrorCodes::MaxTimeMSExpired);
            }
        }
    }

    auto& readConcernArgs = repl::ReadConcernArgs::get(opCtx);

    // If the parent operation runs in a transaction, we don't override the read concern.
    auto skipReadConcern =
        opCtx->getClient()->isInDirectClient() && opCtx->inMultiDocumentTransaction();
    bool startTransaction = static_cast<bool>(_sessionOptions.getStartTransaction());
    if (!skipReadConcern) {
        auto newReadConcernArgs = uassertStatusOK(_extractReadConcern(
            opCtx, _invocation.get(), request.body, startTransaction, _isInternalClient()));

        // Ensure that the RC being set on the opCtx has provenance.
        invariant(newReadConcernArgs.getProvenance().hasSource(),
                  str::stream() << "unexpected unset provenance on readConcern: "
                                << newReadConcernArgs.toBSONInner());

        uassert(ErrorCodes::InvalidOptions,
                "Only the first command in a transaction may specify a readConcern",
                startTransaction || !opCtx->inMultiDocumentTransaction() ||
                    newReadConcernArgs.isEmpty());

        {
            // We must obtain the client lock to set the ReadConcernArgs on the operation context as
            // it may be concurrently read by CurrentOp.
            stdx::lock_guard<Client> lk(*opCtx->getClient());
            readConcernArgs = std::move(newReadConcernArgs);
        }
    }

    if (startTransaction) {
        _setLockStateForTransaction(opCtx);

        // Remember whether or not this operation is starting a transaction, in case something later
        // in the execution needs to adjust its behavior based on this.
        opCtx->setIsStartingMultiDocumentTransaction(true);
    }

    // Once API params and txn state are set on opCtx, enforce the "requireApiVersion" setting.
    enforceRequireAPIVersion(opCtx, command);

    // Check that the client has the directShardOperations role if this is a direct operation to a
    // shard.
    if (command->requiresAuth() && ShardingState::get(opCtx)->enabled() &&
        serverGlobalParams.featureCompatibility.isVersionInitialized() &&
        feature_flags::gCheckForDirectShardOperations.isEnabled(
            serverGlobalParams.featureCompatibility)) {
        bool clusterHasTwoOrMoreShards = [&]() {
            if (feature_flags::gClusterCardinalityParameter.isEnabled(
                    serverGlobalParams.featureCompatibility)) {
                auto* clusterParameters = ServerParameterSet::getClusterParameterSet();
                auto* clusterCardinalityParam =
                    clusterParameters
                        ->get<ClusterParameterWithStorage<ShardedClusterCardinalityParam>>(
                            "shardedClusterCardinalityForDirectConns");
                return clusterCardinalityParam->getValue(boost::none).getHasTwoOrMoreShards();
            }
            return false;
        }();
        if (clusterHasTwoOrMoreShards && !command->shouldSkipDirectConnectionChecks()) {
            const bool authIsEnabled = AuthorizationManager::get(opCtx->getServiceContext()) &&
                AuthorizationManager::get(opCtx->getServiceContext())->isAuthEnabled();

            const bool hasDirectShardOperations = !authIsEnabled ||
                ((AuthorizationSession::get(opCtx->getClient()) != nullptr &&
                  AuthorizationSession::get(opCtx->getClient())
                      ->isAuthorizedForActionsOnResource(ResourcePattern::forClusterResource(),
                                                         ActionType::issueDirectShardOperations)));

            if (!hasDirectShardOperations) {
                bool timeUpdated = false;
                auto currentTime = opCtx->getServiceContext()->getFastClockSource()->now();
                {
                    stdx::lock_guard<Latch> lk(_staticMutex);
                    if ((currentTime - _lastDirectConnectionWarningTime) > Hours(1)) {
                        _lastDirectConnectionWarningTime = currentTime;
                        timeUpdated = true;
                    }
                }
                if (timeUpdated) {
                    LOGV2_WARNING(
                        7553700,
                        "Command should not be run via a direct connection to a shard without the "
                        "directShardOperations role. Please connect via a router.",
                        "command"_attr = request.getCommandName());
                }
                ShardingStatistics::get(opCtx).unauthorizedDirectShardOperations.addAndFetch(1);
            }
        }
    }

    if (!opCtx->getClient()->isInDirectClient() &&
        readConcernArgs.getLevel() != repl::ReadConcernLevel::kAvailableReadConcern &&
        (iAmPrimary || (readConcernArgs.hasLevel() || readConcernArgs.getArgsAfterClusterTime()))) {
        boost::optional<ShardVersion> shardVersion;
        if (auto shardVersionElem = request.body[ShardVersion::kShardVersionField]) {
            shardVersion = ShardVersion::parse(shardVersionElem);
        }

        boost::optional<DatabaseVersion> databaseVersion;
        if (auto databaseVersionElem = request.body[DatabaseVersion::kDatabaseVersionField]) {
            databaseVersion = DatabaseVersion(databaseVersionElem.Obj());
        }

        if (shardVersion || databaseVersion) {
            // If a timeseries collection is sharded, only the buckets collection would be sharded.
            // We expect all versioned commands to be sent over 'system.buckets' namespace. But it
            // is possible that a stale mongos may send the request over a view namespace. In this
            // case, we initialize the 'OperationShardingState' with buckets namespace.
            auto bucketNss = invocationNss.makeTimeseriesBucketsNamespace();
            // Hold reference to the catalog for collection lookup without locks to be safe.
            auto catalog = CollectionCatalog::get(opCtx);
            auto coll = catalog->lookupCollectionByNamespace(opCtx, bucketNss);
            auto namespaceForSharding =
                (coll && coll->getTimeseriesOptions()) ? bucketNss : invocationNss;

            OperationShardingState::setShardRole(
                opCtx, namespaceForSharding, shardVersion, databaseVersion);
        }
    }

    _scoped = _execContext->behaviors->scopedOperationCompletionShardingActions(opCtx);

    // This may trigger the maxTimeAlwaysTimeOut failpoint.
    auto status = opCtx->checkForInterruptNoAssert();

    // We still proceed if the primary stepped down, but accept other kinds of interruptions. We
    // defer to individual commands to allow themselves to be interruptible by stepdowns, since
    // commands like 'voteRequest' should conversely continue executing.
    if (status != ErrorCodes::PrimarySteppedDown &&
        status != ErrorCodes::InterruptedDueToReplStateChange) {
        uassertStatusOK(status);
    }

    CurOp::get(opCtx)->ensureStarted();

    command->incrementCommandsExecuted();

    if (shouldLog(logv2::LogComponent::kTracking, logv2::LogSeverity::Debug(1)) &&
        rpc::TrackingMetadata::get(opCtx).getParentOperId()) {
        LOGV2_DEBUG_OPTIONS(4615605,
                            1,
                            {logv2::LogComponent::kTracking},
                            "Command metadata: {trackingMetadata}",
                            "Command metadata",
                            "trackingMetadata"_attr = rpc::TrackingMetadata::get(opCtx));
        rpc::TrackingMetadata::get(opCtx).setIsLogged(true);
    }
}

Future<void> ExecCommandDatabase::_commandExec() {
    auto opCtx = _execContext->getOpCtx();
    auto& request = _execContext->getRequest();

    _execContext->behaviors->waitForReadConcern(opCtx, _invocation.get(), request);
    _execContext->behaviors->setPrepareConflictBehaviorForReadConcern(opCtx, _invocation.get());

    _execContext->getReplyBuilder()->reset();

    if (OperationShardingState::isComingFromRouter(opCtx)) {
        uassertStatusOK(ShardingState::get(opCtx)->canAcceptShardedCommands());
    }

    auto runCommand = [&] {
        _runCommandOpTimes.emplace(opCtx);
        if (getInvocation()->supportsWriteConcern() ||
            getInvocation()->definition()->getLogicalOp() == LogicalOp::opGetMore) {
            // getMore operations inherit a WriteConcern from their originating cursor. For example,
            // if the originating command was an aggregate with a $out and batchSize: 0. Note that
            // if the command only performed reads then we will not need to wait at all.
            return future_util::makeState<RunCommandAndWaitForWriteConcern>(this).thenWithState(
                [](auto* runner) { return runner->run(); });
        } else {
            return future_util::makeState<RunCommandImpl>(this).thenWithState(
                [](auto* runner) { return runner->run(); });
        }
    };

    return runCommand()
        .onError<ErrorCodes::StaleDbVersion>([this](Status s) -> Future<void> {
            auto opCtx = _execContext->getOpCtx();

            if (!opCtx->getClient()->isInDirectClient() &&
                !serverGlobalParams.clusterRole.exclusivelyHasConfigRole() && !_refreshedDatabase) {
                auto sce = s.extraInfo<StaleDbRoutingVersion>();
                invariant(sce);

                bool stableLocalVersion =
                    !sce->getCriticalSectionSignal() && sce->getVersionWanted();

                if (stableLocalVersion && sce->getVersionReceived() < sce->getVersionWanted()) {
                    // The shard is recovered and the router is staler than the shard, so we cannot
                    // retry locally
                    return s;
                }

                const auto refreshed = _execContext->behaviors->refreshDatabase(opCtx, *sce);
                if (refreshed) {
                    _refreshedDatabase = true;
                    if (!opCtx->isContinuingMultiDocumentTransaction() &&
                        !sce->getCriticalSectionSignal()) {
                        _resetLockerStateAfterShardingUpdate(opCtx);
                        return _commandExec();
                    }
                }
            }

            return s;
        })
        .onErrorCategory<ErrorCategory::StaleShardVersionError>([this](Status s) -> Future<void> {
            auto opCtx = _execContext->getOpCtx();
            ShardingStatistics::get(opCtx).countStaleConfigErrors.addAndFetch(1);

            if (!opCtx->getClient()->isInDirectClient() &&
                !serverGlobalParams.clusterRole.exclusivelyHasConfigRole() &&
                !_refreshedCollection) {
                if (auto sce = s.extraInfo<StaleConfigInfo>()) {
                    bool inCriticalSection = sce->getCriticalSectionSignal().has_value();
                    bool stableLocalVersion = !inCriticalSection && sce->getVersionWanted();

                    if (stableLocalVersion &&
                        ShardVersion::isPlacementVersionIgnored(sce->getVersionReceived())) {
                        // Shard is recovered, but the router didn't sent a shard version, therefore
                        // we just need to tell the router how much it needs to advance to
                        // (getVersionWanted).
                        return s;
                    }

                    if (stableLocalVersion &&
                        sce->getVersionReceived().placementVersion().isOlderThan(
                            sce->getVersionWanted()->placementVersion())) {
                        // Shard is recovered and the router is staler than the shard
                        return s;
                    }

                    if (inCriticalSection) {
                        _execContext->behaviors->handleReshardingCriticalSectionMetrics(opCtx,
                                                                                        *sce);
                    }

                    const auto refreshed = _execContext->behaviors->refreshCollection(opCtx, *sce);
                    if (refreshed) {
                        _refreshedCollection = true;

                        // Can not rerun the command when executing a GetMore command as the cursor
                        // is already lost.
                        const auto isRunningGetMoreCmd =
                            _execContext->getCommand()->getName() == "getMore";
                        if (!opCtx->isContinuingMultiDocumentTransaction() && !inCriticalSection &&
                            !isRunningGetMoreCmd) {
                            _resetLockerStateAfterShardingUpdate(opCtx);
                            return _commandExec();
                        }
                    }
                }
            }

            return s;
        })
        .onError<ErrorCodes::ShardCannotRefreshDueToLocksHeld>([this](Status s) -> Future<void> {
            // This exception can never happen on the config server. Config servers can't receive
            // SSV either, because they never have commands with shardVersion sent.
            invariant(!serverGlobalParams.clusterRole.exclusivelyHasConfigRole());

            auto opCtx = _execContext->getOpCtx();
            if (!opCtx->getClient()->isInDirectClient() && !_refreshedCatalogCache) {
                invariant(!opCtx->lockState()->isLocked());

                auto refreshInfo = s.extraInfo<ShardCannotRefreshDueToLocksHeldInfo>();
                invariant(refreshInfo);

                const auto refreshed =
                    _execContext->behaviors->refreshCatalogCache(opCtx, *refreshInfo);

                if (refreshed) {
                    _refreshedCatalogCache = true;

                    // Can not rerun the command when executing a GetMore command as the cursor is
                    // already lost.
                    const auto isRunningGetMoreCmd =
                        _execContext->getCommand()->getName() == "getMore";
                    if (!opCtx->isContinuingMultiDocumentTransaction() && !isRunningGetMoreCmd) {
                        _resetLockerStateAfterShardingUpdate(opCtx);
                        return _commandExec();
                    }
                }
            }

            return s;
        });
}

void ExecCommandDatabase::_handleFailure(Status status) {
    // Absorb the exception as the command execution has already been skipped.
    if (status.code() == ErrorCodes::SkipCommandExecution)
        return;

    auto opCtx = _execContext->getOpCtx();
    auto& request = _execContext->getRequest();
    auto command = _execContext->getCommand();
    auto replyBuilder = _execContext->getReplyBuilder();
    const auto& behaviors = *_execContext->behaviors;
    onCommandFinished();

    // Append the error labels for transient transaction errors.
    auto response = _extraFieldsBuilder.asTempObj();
    boost::optional<ErrorCodes::Error> wcCode;
    if (response.hasField("writeConcernError")) {
        wcCode = ErrorCodes::Error(response["writeConcernError"]["code"].numberInt());
    }
    appendErrorLabelsAndTopologyVersion(opCtx,
                                        &_extraFieldsBuilder,
                                        _sessionOptions,
                                        command->getName(),
                                        status.code(),
                                        wcCode,
                                        _isInternalClient(),
                                        getLastOpBeforeRun(),
                                        getLastOpAfterRun());
    appendAdditionalParticipants(
        opCtx, &_extraFieldsBuilder, command->getName(), _execContext->nsString().ns());

    BSONObjBuilder metadataBob;
    behaviors.appendReplyMetadata(opCtx, request, &metadataBob);

    // The read concern may not have yet been placed on the operation context, so attempt to parse
    // it here, so if it is valid it can be used to compute the proper operationTime.
    auto& readConcernArgs = repl::ReadConcernArgs::get(opCtx);
    if (readConcernArgs.isEmpty()) {
        auto readConcernArgsStatus = _extractReadConcern(opCtx,
                                                         _invocation.get(),
                                                         request.body,
                                                         false /*startTransaction*/,
                                                         _isInternalClient());
        if (readConcernArgsStatus.isOK()) {
            // We must obtain the client lock to set the ReadConcernArgs on the operation context as
            // it may be concurrently read by CurrentOp.
            stdx::lock_guard<Client> lk(*opCtx->getClient());
            readConcernArgs = readConcernArgsStatus.getValue();
        }
    }
    appendClusterAndOperationTime(opCtx, &_extraFieldsBuilder, &metadataBob, _startOperationTime);

    LOGV2_DEBUG(21962,
                1,
                "Assertion while executing command '{command}' on database '{db}' with "
                "arguments '{commandArgs}': {error}",
                "Assertion while executing command",
                "command"_attr = request.getCommandName(),
                "db"_attr = request.getDatabase(),
                "commandArgs"_attr = redact(
                    ServiceEntryPointCommon::getRedactedCopyForLogging(command, request.body)),
                "error"_attr = redact(status.toString()));

    generateErrorResponse(
        opCtx, replyBuilder, status, metadataBob.obj(), _extraFieldsBuilder.obj());

    if (ErrorCodes::isA<ErrorCategory::CloseConnectionError>(status.code())) {
        // Rethrow the exception to the top to signal that the client connection should be closed.
        iassert(status);
    }
}

/**
 * Fills out CurOp / OpDebug with basic command info.
 */
void curOpCommandSetup(OperationContext* opCtx, const OpMsgRequest& request) {
    auto curop = CurOp::get(opCtx);
    curop->debug().iscommand = true;

    // We construct a legacy $cmd namespace so we can fill in curOp using
    // the existing logic that existed for OP_QUERY commands
    NamespaceString nss(NamespaceString::makeCommandNamespace(
        DatabaseNameUtil::deserialize(request.getValidatedTenantId(), request.getDatabase())));

    stdx::lock_guard<Client> lk(*opCtx->getClient());
    curop->setNS_inlock(nss);
    curop->setOpDescription_inlock(request.body);
    curop->markCommand_inlock();
}

Future<void> parseCommand(std::shared_ptr<HandleRequest::ExecutionContext> execContext) try {
    const auto& msg = execContext->getMessage();
    auto client = execContext->getOpCtx()->getClient();
    auto opMsgReq = rpc::opMsgRequestFromAnyProtocol(msg, client);

    if (msg.operation() == dbQuery) {
        checkAllowedOpQueryCommand(*client, opMsgReq.getCommandName());
    }
    execContext->setRequest(opMsgReq);
    return Status::OK();
} catch (const DBException& ex) {
    // Need to set request as `makeCommandResponse` expects an empty request on failure.
    execContext->setRequest({});

    // Otherwise, reply with the parse error. This is useful for cases where parsing fails due to
    // user-supplied input, such as the document too deep error. Since we failed during parsing, we
    // can't log anything about the command.
    LOGV2_DEBUG(21963,
                1,
                "Assertion while parsing command: {error}",
                "Assertion while parsing command",
                "error"_attr = ex.toString());

    return ex.toStatus();
}

Future<void> executeCommand(std::shared_ptr<HandleRequest::ExecutionContext> execContext) {
    auto [past, present] = makePromiseFuture<void>();
    auto future =
        std::move(present)
            .then([execContext]() -> Future<void> {
                // Prepare environment for command execution (e.g., find command object in registry)
                auto opCtx = execContext->getOpCtx();
                auto& request = execContext->getRequest();
                curOpCommandSetup(opCtx, request);

                // In the absence of a Command object, no redaction is possible. Therefore to avoid
                // displaying potentially sensitive information in the logs, we restrict the log
                // message to the name of the unrecognized command. However, the complete command
                // object will still be echoed to the client.
                if (execContext->setCommand(CommandHelpers::findCommand(request.getCommandName()));
                    !execContext->getCommand()) {
                    globalCommandRegistry()->incrementUnknownCommands();
                    LOGV2_DEBUG(21964,
                                2,
                                "No such command: {command}",
                                "Command not found in registry",
                                "command"_attr = request.getCommandName());
                    return Status(ErrorCodes::CommandNotFound,
                                  fmt::format("no such command: '{}'", request.getCommandName()));
                }

                Command* c = execContext->getCommand();
                LOGV2_DEBUG(
                    21965,
                    2,
                    "Run command {db}.$cmd {commandArgs}",
                    "About to run the command",
                    "db"_attr = request.getDatabase(),
                    "client"_attr = (opCtx->getClient() && opCtx->getClient()->hasRemote()
                                         ? opCtx->getClient()->getRemote().toString()
                                         : ""),
                    "commandArgs"_attr = redact(
                        ServiceEntryPointCommon::getRedactedCopyForLogging(c, request.body)));

                {
                    // Try to set this as early as possible, as soon as we have figured out the
                    // command.
                    stdx::lock_guard<Client> lk(*opCtx->getClient());
                    CurOp::get(opCtx)->setLogicalOp_inlock(c->getLogicalOp());
                }

                opCtx->setExhaust(
                    OpMsg::isFlagSet(execContext->getMessage(), OpMsg::kExhaustSupported));

                return Status::OK();
            })
            .then([execContext]() mutable {
                return future_util::makeState<ExecCommandDatabase>(std::move(execContext))
                    .thenWithState([](auto* runner) { return runner->run(); });
            })
            .tapError([execContext](Status status) {
                LOGV2_DEBUG(
                    21966,
                    1,
                    "Assertion while executing command '{command}' on database '{db}': {error}",
                    "Assertion while executing command",
                    "command"_attr = execContext->getRequest().getCommandName(),
                    "db"_attr = execContext->getRequest().getDatabase(),
                    "error"_attr = status.toString());
            });
    past.emplaceValue();
    return future;
}

DbResponse makeCommandResponse(std::shared_ptr<HandleRequest::ExecutionContext> execContext) {
    auto opCtx = execContext->getOpCtx();
    const Message& message = execContext->getMessage();
    OpMsgRequest request = execContext->getRequest();
    const Command* c = execContext->getCommand();
    auto replyBuilder = execContext->getReplyBuilder();

    if (OpMsg::isFlagSet(message, OpMsg::kMoreToCome)) {
        // Close the connection to get client to go through server selection again.
        if (NotPrimaryErrorTracker::get(opCtx->getClient()).hadError()) {
            if (c && c->getReadWriteType() == Command::ReadWriteType::kWrite)
                notPrimaryUnackWrites.increment();

            uasserted(ErrorCodes::NotWritablePrimary,
                      str::stream()
                          << "Not-primary error while processing '" << request.getCommandName()
                          << "' operation  on '" << request.getDatabase() << "' database via "
                          << "fire-and-forget command execution.");
        }
        return {};  // Don't reply.
    }

    DbResponse dbResponse;
    CommandHelpers::checkForInternalError(replyBuilder, execContext->isInternalClient());

    if (OpMsg::isFlagSet(message, OpMsg::kExhaustSupported)) {
        auto responseObj = replyBuilder->getBodyBuilder().asTempObj();

        if (responseObj.getField("ok").trueValue()) {
            dbResponse.shouldRunAgainForExhaust = replyBuilder->shouldRunAgainForExhaust();
            dbResponse.nextInvocation = replyBuilder->getNextInvocation();
        }
    }

    try {
        dbResponse.response = replyBuilder->done();
    } catch (const ExceptionFor<ErrorCodes::BSONObjectTooLarge>& ex) {
        // Create a new reply builder as subsequently calling any methods on a builder after
        // 'done()' results in undefined behavior.
        auto errorReplyBuilder = execContext->getReplyBuilder();
        BSONObjBuilder metadataBob;
        BSONObjBuilder extraFieldsBuilder;
        appendClusterAndOperationTime(
            opCtx, &extraFieldsBuilder, &metadataBob, LogicalTime::kUninitialized);
        generateErrorResponse(
            opCtx, errorReplyBuilder, ex.toStatus(), metadataBob.obj(), extraFieldsBuilder.obj());
        dbResponse.response = errorReplyBuilder->done();
    }
    CurOp::get(opCtx)->debug().responseLength = dbResponse.response.header().dataLen();

    return dbResponse;
}

Future<DbResponse> receivedCommands(std::shared_ptr<HandleRequest::ExecutionContext> execContext) {
    execContext->setReplyBuilder(
        rpc::makeReplyBuilder(rpc::protocolForMessage(execContext->getMessage())));
    return parseCommand(execContext)
        .then([execContext]() mutable { return executeCommand(std::move(execContext)); })
        .onError([execContext](Status status) {
            if (ErrorCodes::isConnectionFatalMessageParseError(status.code())) {
                // If this error needs to fail the connection, propagate it out.
                iassert(status);
            }

            auto opCtx = execContext->getOpCtx();
            BSONObjBuilder metadataBob;
            BSONObjBuilder extraFieldsBuilder;
            appendClusterAndOperationTime(
                opCtx, &extraFieldsBuilder, &metadataBob, LogicalTime::kUninitialized);

            auto replyBuilder = execContext->getReplyBuilder();
            generateErrorResponse(
                opCtx, replyBuilder, status, metadataBob.obj(), extraFieldsBuilder.obj());

            if (ErrorCodes::isA<ErrorCategory::CloseConnectionError>(status.code())) {
                // Return the exception to the top to signal that the client connection should be
                // closed.
                iassert(status);
            }
        })
        .then([execContext]() mutable { return makeCommandResponse(std::move(execContext)); });
}

struct CommandOpRunner : HandleRequest::OpRunner {
    using HandleRequest::OpRunner::OpRunner;
    Future<DbResponse> run() override {
        return receivedCommands(executionContext);
    }
};

// Allows wrapping synchronous code in futures without repeating the try-catch block.
struct SynchronousOpRunner : HandleRequest::OpRunner {
    using HandleRequest::OpRunner::OpRunner;
    virtual DbResponse runSync() = 0;
    Future<DbResponse> run() final try { return runSync(); } catch (const DBException& ex) {
        return ex.toStatus();
    }
};

struct QueryOpRunner : SynchronousOpRunner {
    using SynchronousOpRunner::SynchronousOpRunner;
    DbResponse runSync() override {
        invariant(!executionContext->nsString().isCommand());
        return makeErrorResponseToUnsupportedOpQuery("OP_QUERY is no longer supported");
    }
};

struct GetMoreOpRunner : SynchronousOpRunner {
    using SynchronousOpRunner::SynchronousOpRunner;
    DbResponse runSync() override {
        return makeErrorResponseToUnsupportedOpQuery("OP_GET_MORE is no longer supported");
    }
};

/**
 * Fire and forget network operations don't produce a `DbResponse`.
 * They override `runAndForget` instead of `run`, and this base
 * class provides a `run` that calls it and handles error reporting
 * via the `NotPrimaryErrorTracker` slot.
 */
struct FireAndForgetOpRunner : SynchronousOpRunner {
    using SynchronousOpRunner::SynchronousOpRunner;
    virtual void runAndForget() = 0;
    DbResponse runSync() final;
};

struct KillCursorsOpRunner : FireAndForgetOpRunner {
    using FireAndForgetOpRunner::FireAndForgetOpRunner;
    void runAndForget() override {
        uasserted(5745703, "OP_KILL_CURSORS is no longer supported");
    }
};

struct InsertOpRunner : FireAndForgetOpRunner {
    using FireAndForgetOpRunner::FireAndForgetOpRunner;
    void runAndForget() override {
        uasserted(5745702, "OP_INSERT is no longer supported");
    }
};

struct UpdateOpRunner : FireAndForgetOpRunner {
    using FireAndForgetOpRunner::FireAndForgetOpRunner;
    void runAndForget() override {
        uasserted(5745701, "OP_UPDATE is no longer supported");
    }
};

struct DeleteOpRunner : FireAndForgetOpRunner {
    using FireAndForgetOpRunner::FireAndForgetOpRunner;
    void runAndForget() override {
        uasserted(5745700, "OP_DELETE is no longer supported");
    }
};

struct UnsupportedOpRunner : SynchronousOpRunner {
    using SynchronousOpRunner::SynchronousOpRunner;
    DbResponse runSync() override {
        // For compatibility reasons, we only log incidents of receiving operations that are not
        // supported and return an empty response to the caller.
        LOGV2(21968,
              "Operation isn't supported: {operation}",
              "Operation is not supported",
              "operation"_attr = static_cast<int>(executionContext->op()));
        executionContext->currentOp().done();
        executionContext->forceLog = true;
        return {};
    }
};

std::unique_ptr<HandleRequest::OpRunner> HandleRequest::makeOpRunner() {
    switch (executionContext->op()) {
        case dbQuery:
            if (!executionContext->nsString().isCommand())
                return std::make_unique<QueryOpRunner>(this);
            // Fallthrough because it's a query containing a command. Ideally, we'd like to let
            // through only hello|isMaster commands but at this point the command hasn't been parsed
            // yet, so we don't know what it is.
            [[fallthrough]];
        case dbMsg:
            return std::make_unique<CommandOpRunner>(this);
        case dbGetMore:
            return std::make_unique<GetMoreOpRunner>(this);
        case dbKillCursors:
            return std::make_unique<KillCursorsOpRunner>(this);
        case dbInsert:
            return std::make_unique<InsertOpRunner>(this);
        case dbUpdate:
            return std::make_unique<UpdateOpRunner>(this);
        case dbDelete:
            return std::make_unique<DeleteOpRunner>(this);
        default:
            return std::make_unique<UnsupportedOpRunner>(this);
    }
}

DbResponse FireAndForgetOpRunner::runSync() {
    runAndForget();
    return {};
}

void HandleRequest::startOperation() {
    auto opCtx = executionContext->getOpCtx();
    auto& client = executionContext->client();
    auto& currentOp = executionContext->currentOp();

    if (client.isInDirectClient()) {
        if (!opCtx->getLogicalSessionId() || !opCtx->getTxnNumber()) {
            invariant(!opCtx->inMultiDocumentTransaction() &&
                      !opCtx->lockState()->inAWriteUnitOfWork());
        }
    } else {
        NotPrimaryErrorTracker::get(client).startRequest();
        AuthorizationSession::get(client)->startRequest(opCtx);

        // We should not be holding any locks at this point
        invariant(!opCtx->lockState()->isLocked());
    }
    {
        stdx::lock_guard<Client> lk(client);
        // Commands handling code will reset this if the operation is a command
        // which is logically a basic CRUD operation like query, insert, etc.
        currentOp.setNetworkOp_inlock(executionContext->op());
        currentOp.setLogicalOp_inlock(networkOpToLogicalOp(executionContext->op()));
    }
}

void HandleRequest::completeOperation(DbResponse& response) {
    auto opCtx = executionContext->getOpCtx();
    auto& currentOp = executionContext->currentOp();

    // Mark the op as complete, and log it if appropriate. Returns a boolean indicating whether
    // this op should be written to the profiler.
    const bool shouldProfile = currentOp.completeAndLogOperation(
        MONGO_LOGV2_DEFAULT_COMPONENT,
        CollectionCatalog::get(opCtx)
            ->getDatabaseProfileSettings(currentOp.getNSS().dbName())
            .filter,
        response.response.size(),
        executionContext->slowMsOverride,
        executionContext->forceLog);

    Top::get(opCtx->getServiceContext())
        .incrementGlobalLatencyStats(
            opCtx,
            durationCount<Microseconds>(currentOp.elapsedTimeExcludingPauses()),
            currentOp.getReadWriteType());

    if (shouldProfile) {
        // Performance profiling is on
        if (opCtx->lockState()->isReadLocked()) {
            LOGV2_DEBUG(21970, 1, "Note: not profiling because of recursive read lock");
        } else if (executionContext->client().isInDirectClient()) {
            LOGV2_DEBUG(21971, 1, "Note: not profiling because we are in DBDirectClient");
        } else if (executionContext->behaviors->lockedForWriting()) {
            // TODO SERVER-26825: Fix race condition where fsyncLock is acquired post
            // lockedForWriting() call but prior to profile collection lock acquisition.
            LOGV2_DEBUG(21972, 1, "Note: not profiling because doing fsync+lock");
        } else if (opCtx->readOnly()) {
            LOGV2_DEBUG(21973, 1, "Note: not profiling because server is read-only");
        } else {
            invariant(!opCtx->lockState()->inAWriteUnitOfWork());
            profile(opCtx, executionContext->op());
        }
    }

    recordCurOpMetrics(opCtx);

    const auto& stats =
        CurOp::get(opCtx)->getReadOnlyUserAcquisitionStats()->getLdapOperationStats();
    if (stats.shouldReport()) {
        auto ldapCumulativeOperationsStats = LDAPCumulativeOperationStats::get();
        if (nullptr != ldapCumulativeOperationsStats) {
            ldapCumulativeOperationsStats->recordOpStats(stats, false);
        }
    }
}

}  // namespace

BSONObj ServiceEntryPointCommon::getRedactedCopyForLogging(const Command* command,
                                                           const BSONObj& cmdObj) {
    mutablebson::Document cmdToLog(cmdObj, mutablebson::Document::kInPlaceDisabled);
    command->snipForLogging(&cmdToLog);
    BSONObjBuilder bob;
    cmdToLog.writeTo(&bob);
    return bob.obj();
}

void logHandleRequestFailure(const Status& status) {
    LOGV2_ERROR(4879802, "Failed to handle request", "error"_attr = redact(status));
}

void onHandleRequestException(const HandleRequest& hr, const Status& status) {
    auto isMirrorOp = [&] {
        const auto& obj = hr.executionContext->getRequest().body;
        if (auto e = obj.getField("mirrored"); MONGO_unlikely(e.ok() && e.boolean()))
            return true;
        return false;
    };

    // TODO SERVER-70510 revert changes introduced by SERVER-60553 that suppresses errors occurred
    // during handling of mirroring operations on recovering secondaries.
    if (MONGO_unlikely(status == ErrorCodes::NotWritablePrimary && isMirrorOp()))
        return;

    logHandleRequestFailure(status);
}

Future<DbResponse> ServiceEntryPointCommon::handleRequest(
    OperationContext* opCtx, const Message& m, std::unique_ptr<const Hooks> behaviors) noexcept
    try {
    HandleRequest hr(opCtx, m, std::move(behaviors));
    hr.startOperation();

    auto opRunner = hr.makeOpRunner();
    invariant(opRunner);

    return opRunner->run()
        .then([&hr](DbResponse response) mutable {
            hr.completeOperation(response);

            auto opCtx = hr.executionContext->getOpCtx();
            if (auto seCtx = transport::ServiceExecutorContext::get(opCtx->getClient())) {
                if (auto invocation = CommandInvocation::get(opCtx);
                    invocation && !invocation->isSafeForBorrowedThreads()) {
                    // If the last command wasn't safe for a borrowed thread, then let's move
                    // off of it.
                    seCtx->setUseDedicatedThread(true);
                }
            }

            return response;
        })
        .tapError([hr = std::move(hr)](Status status) { onHandleRequestException(hr, status); });
} catch (const DBException& ex) {
    auto status = ex.toStatus();
    logHandleRequestFailure(status);
    return status;
}

ServiceEntryPointCommon::Hooks::~Hooks() = default;

}  // namespace mongo