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/**
* 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.
*/
#pragma once
#include <string>
#include <vector>
#include "mongo/base/status.h"
#include "mongo/base/string_data.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/jsobj.h"
#include "mongo/rpc/write_concern_error_detail.h"
#include "mongo/s/async_requests_sender.h"
#include "mongo/s/catalog_cache.h"
#include "mongo/s/commands/strategy.h"
#include "mongo/stdx/memory.h"
namespace mongo {
/**
* This function appends the provided writeConcernError BSONElement to the sharded response.
*/
void appendWriteConcernErrorToCmdResponse(const ShardId& shardID,
const BSONElement& wcErrorElem,
BSONObjBuilder& responseBuilder);
/**
* Creates and returns a WriteConcernErrorDetail object from a BSONObj.
*/
std::unique_ptr<WriteConcernErrorDetail> getWriteConcernErrorDetailFromBSONObj(const BSONObj& obj);
/**
* Dispatches all the specified requests in parallel and waits until all complete, returning a
* vector of the same size and positions as that of 'requests'.
*
* Throws StaleConfigException if any remote returns a stale shardVersion error.
*/
std::vector<AsyncRequestsSender::Response> gatherResponses(
OperationContext* opCtx,
StringData dbName,
const ReadPreferenceSetting& readPref,
Shard::RetryPolicy retryPolicy,
const std::vector<AsyncRequestsSender::Request>& requests,
const std::set<ErrorCodes::Error>& ignorableErrors = {});
/**
* Returns a copy of 'cmdObj' with 'version' appended.
*/
BSONObj appendShardVersion(BSONObj cmdObj, ChunkVersion version);
/**
* Returns a copy of 'cmdObj' with 'allowImplicitCollectionCreation' appended.
*/
BSONObj appendAllowImplicitCreate(BSONObj cmdObj, bool allow);
/**
* Returns a copy of 'cmdObj' with the writeConcern removed.
*/
BSONObj stripWriteConcern(const BSONObj& cmdObj);
/**
* Utility for dispatching unversioned commands to all shards in a cluster.
*
* Returns a non-OK status if a failure occurs on *this* node during execution. Otherwise, returns
* success and a list of responses from shards (including errors from the shards or errors reaching
* the shards).
*
* Note, if this mongos has not refreshed its shard list since
* 1) a shard has been *added* through a different mongos, a request will not be sent to the added
* shard
* 2) a shard has been *removed* through a different mongos, this function will return a
* ShardNotFound error status.
*/
std::vector<AsyncRequestsSender::Response> scatterGatherUnversionedTargetAllShards(
OperationContext* opCtx,
StringData dbName,
const BSONObj& cmdObj,
const ReadPreferenceSetting& readPref,
Shard::RetryPolicy retryPolicy);
/**
* Utility for dispatching versioned commands on a namespace, deciding which shards to
* target by applying the passed-in query and collation to the local routing table cache.
*
* Does not retry on StaleConfigException.
*
* Return value is the same as scatterGatherUnversionedTargetAllShards().
*/
std::vector<AsyncRequestsSender::Response> scatterGatherVersionedTargetByRoutingTable(
OperationContext* opCtx,
StringData dbName,
const NamespaceString& nss,
const CachedCollectionRoutingInfo& routingInfo,
const BSONObj& cmdObj,
const ReadPreferenceSetting& readPref,
Shard::RetryPolicy retryPolicy,
const BSONObj& query,
const BSONObj& collation);
/**
* Utility for dispatching commands on a namespace, but with special hybrid versioning:
* - If the namespace is unsharded, a version is attached (so this node can find out if its routing
* table was stale, and the namespace is actually sharded), and only the primary shard is targeted.
* - If the namespace is sharded, no version is attached, and the request is broadcast to all
* shards.
*
* Does not retry on StaleConfigException.
*
* Return value is the same as scatterGatherUnversionedTargetAllShards().
*/
std::vector<AsyncRequestsSender::Response> scatterGatherOnlyVersionIfUnsharded(
OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& cmdObj,
const ReadPreferenceSetting& readPref,
Shard::RetryPolicy retryPolicy,
const std::set<ErrorCodes::Error>& ignorableErrors = {});
/**
* Utility for dispatching commands against the primary of a database and attach the appropriate
* database version.
*
* Does not retry on StaleDbVersion.
*/
AsyncRequestsSender::Response executeCommandAgainstDatabasePrimary(
OperationContext* opCtx,
StringData dbName,
const CachedDatabaseInfo& dbInfo,
const BSONObj& cmdObj,
const ReadPreferenceSetting& readPref,
Shard::RetryPolicy retryPolicy);
/**
* Attaches each shard's response or error status by the shard's connection string in a top-level
* field called 'raw' in 'output'.
*
* If all shards that errored had the same error, writes the common error code to 'output'. Writes a
* string representation of all errors to 'errmsg.' Errors codes in 'ignoredErrors' are not treated
* as errors if any shard returned success.
*
* Returns true if any shard reports success and only ignored errors occur.
*/
bool appendRawResponses(OperationContext* opCtx,
std::string* errmsg,
BSONObjBuilder* output,
const std::vector<AsyncRequestsSender::Response>& shardResponses,
std::set<ErrorCodes::Error> ignoredErrors = {});
/**
* Extracts the query from a query-embedding command ('query' or 'q' fields). If the command does
* not have an embedded query, returns an empty BSON object.
*/
BSONObj extractQuery(const BSONObj& cmdObj);
/**
* Extracts the collation from a collation-embedding command ('collation' field). If the command
* does not specify a collation, returns an empty BSON object. If the 'collation' field is of wrong
* type, throws.
*/
BSONObj extractCollation(const BSONObj& cmdObj);
/**
* Utility function to compute a single error code from a vector of command results.
*
* @return If there is an error code common to all of the error results, returns that error
* code; otherwise, returns 0.
*/
int getUniqueCodeFromCommandResults(const std::vector<Strategy::CommandResult>& results);
/**
* Utility function to return an empty result set from a command.
*/
bool appendEmptyResultSet(OperationContext* opCtx,
BSONObjBuilder& result,
Status status,
const std::string& ns);
/**
* If the specified database exists already, loads it in the cache (if not already there).
* Otherwise, if it does not exist, this call will implicitly create it as non-sharded.
*/
void createShardDatabase(OperationContext* opCtx, StringData dbName);
/**
* Returns the shards that would be targeted for the given query according to the given routing
* info.
*/
std::set<ShardId> getTargetedShardsForQuery(OperationContext* opCtx,
const CachedCollectionRoutingInfo& routingInfo,
const BSONObj& query,
const BSONObj& collation);
/**
* Determines the shard(s) to which the given query will be targeted, and builds a separate
* versioned copy of the command object for each such shard.
*/
std::vector<std::pair<ShardId, BSONObj>> getVersionedRequestsForTargetedShards(
OperationContext* opCtx,
const NamespaceString& nss,
const CachedCollectionRoutingInfo& routingInfo,
const BSONObj& cmdObj,
const BSONObj& query,
const BSONObj& collation);
/**
* If the command is running in a transaction, returns the proper routing table to use for targeting
* shards. If there is no active transaction or the transaction is not running with snapshot level
* read concern, the latest routing table is returned, otherwise a historical routing table is
* returned at the global read timestamp, which must have been selected by this point.
*
* Should be used by all router commands that can be run in a transaction when targeting shards.
*/
StatusWith<CachedCollectionRoutingInfo> getCollectionRoutingInfoForTxnCmd(
OperationContext* opCtx, const NamespaceString& nss);
/**
* Utility for dispatching a command on a namespace that is sent to all shards. If all shards return
* CannotImplicitlyCreateCollection, will throw. If at least one shard succeeds, will ignore
* CannotImplicitlyCreateCollection errors.
*/
std::vector<AsyncRequestsSender::Response> dispatchCommandAssertCollectionExistsOnAtLeastOneShard(
OperationContext* opCtx,
const NamespaceString& nss,
const ReadPreference readPreference,
const BSONObj& cmdObj);
} // namespace mongo
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