path: root/src/mongo/s/commands/document_shard_key_update_util.cpp

/**
 *    Copyright (C) 2019-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/platform/basic.h"

#include "mongo/s/commands/document_shard_key_update_util.h"

#include "mongo/base/status_with.h"
#include "mongo/db/namespace_string.h"
#include "mongo/logv2/log.h"
#include "mongo/s/cluster_write.h"
#include "mongo/s/would_change_owning_shard_exception.h"
#include "mongo/s/write_ops/batched_command_request.h"
#include "mongo/s/write_ops/batched_command_response.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/str.h"

#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding


namespace mongo {
namespace {

MONGO_FAIL_POINT_DEFINE(hangBeforeInsertOnUpdateShardKey);

/**
 * Calls into the command execution stack to run the given command. Will blindly uassert on any
 * error returned by a command. If the original update was sent with {upsert: false}, returns
 * whether or not we deleted the original doc and inserted the new one sucessfully. If the original
 * update was sent with {upsert: true}, returns whether or not we inserted the new doc successfully.
 */
bool executeOperationsAsPartOfShardKeyUpdate(OperationContext* opCtx,
                                             const BSONObj& deleteCmdObj,
                                             const BSONObj& insertCmdObj,
                                             const StringData db,
                                             const bool shouldUpsert) {
    auto deleteOpMsg = OpMsgRequest::fromDBAndBody(db, deleteCmdObj);
    auto deleteRequest = BatchedCommandRequest::parseDelete(deleteOpMsg);

    BatchedCommandResponse deleteResponse;
    BatchWriteExecStats deleteStats;
    cluster::write(opCtx, deleteRequest, &deleteStats, &deleteResponse);
    uassertStatusOKWithContext(deleteResponse.toStatus(),
                               "During delete stage of updating a shard key");

    // If shouldUpsert is true, this means the original command specified {upsert: true} and did not
    // match any docs, so we should not match any when doing this delete. If shouldUpsert is false
    // and we do not delete any document, this is essentially equivalent to not matching a doc and
    // we should not insert.
    if (shouldUpsert) {
        uassert(ErrorCodes::ConflictingOperationInProgress,
                "Delete matched a document when it should not have.",
                deleteResponse.getN() == 0);
    } else if (deleteResponse.getN() != 1) {
        return false;
    }

    if (MONGO_unlikely(hangBeforeInsertOnUpdateShardKey.shouldFail())) {
        LOGV2(22760, "Hit hangBeforeInsertOnUpdateShardKey failpoint");
        hangBeforeInsertOnUpdateShardKey.pauseWhileSet(opCtx);
    }

    auto insertOpMsg = OpMsgRequest::fromDBAndBody(db, insertCmdObj);
    auto insertRequest = BatchedCommandRequest::parseInsert(insertOpMsg);

    BatchedCommandResponse insertResponse;
    BatchWriteExecStats insertStats;
    cluster::write(opCtx, insertRequest, &insertStats, &insertResponse);
    uassertStatusOKWithContext(insertResponse.toStatus(),
                               "During insert stage of updating a shard key");

    uassert(ErrorCodes::NamespaceNotFound,
            "Document not successfully inserted while changing shard key for namespace " +
                insertRequest.getNS().toStringForErrorMsg(),
            insertResponse.getN() == 1);

    return true;
}

/**
 * Creates the delete op that will be used to delete the pre-image document. Will also attach the
 * original document _id retrieved from 'updatePreImage'.
 */
write_ops::DeleteCommandRequest createShardKeyDeleteOp(const NamespaceString& nss,
                                                       const BSONObj& updatePreImage) {
    write_ops::DeleteCommandRequest deleteOp(nss);
    deleteOp.setDeletes({[&] {
        write_ops::DeleteOpEntry entry;
        entry.setQ(updatePreImage);
        entry.setMulti(false);
        return entry;
    }()});

    return deleteOp;
}

/**
 * Creates the insert op that will be used to insert the new document with the post-update image.
 */
write_ops::InsertCommandRequest createShardKeyInsertOp(const NamespaceString& nss,
                                                       const BSONObj& updatePostImage,
                                                       bool fleCrudProcessed) {
    write_ops::InsertCommandRequest insertOp(nss);
    insertOp.setDocuments({updatePostImage});
    if (fleCrudProcessed) {
        EncryptionInformation encryptionInformation;
        encryptionInformation.setCrudProcessed(fleCrudProcessed);

        // We need to set an empty BSON object here for the schema.
        encryptionInformation.setSchema(BSONObj());
        insertOp.getWriteCommandRequestBase().setEncryptionInformation(encryptionInformation);
    }
    return insertOp;
}

}  //  namespace

namespace documentShardKeyUpdateUtil {

bool updateShardKeyForDocumentLegacy(OperationContext* opCtx,
                                     const NamespaceString& nss,
                                     const WouldChangeOwningShardInfo& documentKeyChangeInfo,
                                     bool fleCrudProcessed) {
    auto updatePreImage = documentKeyChangeInfo.getPreImage().getOwned();
    auto updatePostImage = documentKeyChangeInfo.getPostImage().getOwned();

    auto deleteCmdObj = constructShardKeyDeleteCmdObj(nss, updatePreImage);
    auto insertCmdObj = constructShardKeyInsertCmdObj(nss, updatePostImage, fleCrudProcessed);

    return executeOperationsAsPartOfShardKeyUpdate(
        opCtx, deleteCmdObj, insertCmdObj, nss.db(), documentKeyChangeInfo.getShouldUpsert());
}

void startTransactionForShardKeyUpdate(OperationContext* opCtx) {
    auto txnRouter = TransactionRouter::get(opCtx);
    invariant(txnRouter);

    auto txnNumber = opCtx->getTxnNumber();
    invariant(txnNumber);

    txnRouter.beginOrContinueTxn(opCtx, *txnNumber, TransactionRouter::TransactionActions::kStart);
}

BSONObj commitShardKeyUpdateTransaction(OperationContext* opCtx) {
    auto txnRouter = TransactionRouter::get(opCtx);
    invariant(txnRouter);

    return txnRouter.commitTransaction(opCtx, boost::none);
}

BSONObj constructShardKeyDeleteCmdObj(const NamespaceString& nss, const BSONObj& updatePreImage) {
    auto deleteOp = createShardKeyDeleteOp(nss, updatePreImage);
    return deleteOp.toBSON({});
}

BSONObj constructShardKeyInsertCmdObj(const NamespaceString& nss,
                                      const BSONObj& updatePostImage,
                                      bool fleCrudProcessed) {
    auto insertOp = createShardKeyInsertOp(nss, updatePostImage, fleCrudProcessed);
    return insertOp.toBSON({});
}

SemiFuture<bool> updateShardKeyForDocument(const txn_api::TransactionClient& txnClient,
                                           ExecutorPtr txnExec,
                                           const NamespaceString& nss,
                                           const WouldChangeOwningShardInfo& changeInfo,
                                           bool fleCrudProcessed) {
    auto deleteCmdObj = documentShardKeyUpdateUtil::constructShardKeyDeleteCmdObj(
        nss, changeInfo.getPreImage().getOwned());
    auto deleteOpMsg = OpMsgRequest::fromDBAndBody(nss.db(), std::move(deleteCmdObj));
    auto deleteRequest = BatchedCommandRequest::parseDelete(std::move(deleteOpMsg));

    // Retry history for this delete isn't necessary, but it can be part of a retryable transaction,
    // so send it with the uninitialized sentinel statement id to opt out of storing history.
    return txnClient.runCRUDOp(deleteRequest, {kUninitializedStmtId})
        .thenRunOn(txnExec)
        .then([&txnClient, &nss, &changeInfo, fleCrudProcessed](
                  auto deleteResponse) -> SemiFuture<BatchedCommandResponse> {
            uassertStatusOK(deleteResponse.toStatus());

            // If shouldUpsert is true, this means the original command specified {upsert:
            // true} and did not match any docs, so we should not match any when doing
            // this delete. If shouldUpsert is false and we do not delete any document,
            // this is essentially equivalent to not matching a doc and we should not
            // insert.
            if (changeInfo.getShouldUpsert()) {
                uassert(ErrorCodes::ConflictingOperationInProgress,
                        "Delete matched a document when it should not have.",
                        deleteResponse.getN() == 0);
            } else if (deleteResponse.getN() != 1) {
                iassert(Status(ErrorCodes::WouldChangeOwningShardDeletedNoDocument,
                               "When handling WouldChangeOwningShard error, the delete matched no "
                               "documents and should not upsert"));
            }

            if (MONGO_unlikely(hangBeforeInsertOnUpdateShardKey.shouldFail())) {
                LOGV2(5918602, "Hit hangBeforeInsertOnUpdateShardKey failpoint");
                hangBeforeInsertOnUpdateShardKey.pauseWhileSet();
            }

            auto insertCmdObj = documentShardKeyUpdateUtil::constructShardKeyInsertCmdObj(
                nss, changeInfo.getPostImage().getOwned(), fleCrudProcessed);
            auto insertOpMsg = OpMsgRequest::fromDBAndBody(nss.db(), std::move(insertCmdObj));
            auto insertRequest = BatchedCommandRequest::parseInsert(std::move(insertOpMsg));

            // Same as for the insert, retry history isn't necessary so opt out with a sentinel
            // stmtId.
            return txnClient.runCRUDOp(insertRequest, {kUninitializedStmtId});
        })
        .thenRunOn(txnExec)
        .then([&nss](auto insertResponse) {
            uassertStatusOK(insertResponse.toStatus());

            uassert(ErrorCodes::NamespaceNotFound,
                    "Document not successfully inserted while changing shard key for namespace " +
                        nss.toStringForErrorMsg(),
                    insertResponse.getN() == 1);

            return true;
        })
        .onError<ErrorCodes::WouldChangeOwningShardDeletedNoDocument>([](Status status) {
            // We failed to delete a document and were not configured to upsert, so the insert
            // was never sent. Propagate that failure by returning false.
            return false;
        })
        .semi();
}

}  // namespace documentShardKeyUpdateUtil
}  // namespace mongo