C++ WriteConcernOptions类代码示例

StatusWith<MigrationSecondaryThrottleOptions>
MigrationSecondaryThrottleOptions::createFromBalancerConfig(const BSONObj& obj) {
    {
        bool isSecondaryThrottle;
        Status status =
            bsonExtractBooleanField(obj, kSecondaryThrottleMongos, &isSecondaryThrottle);
        if (status.isOK()) {
            return MigrationSecondaryThrottleOptions::create(isSecondaryThrottle ? kOn : kOff);
        } else if (status == ErrorCodes::NoSuchKey) {
            return MigrationSecondaryThrottleOptions::create(kDefault);
        } else if (status != ErrorCodes::TypeMismatch) {
            return status;
        }
    }

    // Try to load it as a BSON document
    BSONElement elem;
    Status status = bsonExtractTypedField(obj, kSecondaryThrottleMongos, BSONType::Object, &elem);

    WriteConcernOptions writeConcern;
    Status writeConcernParseStatus = writeConcern.parse(elem.Obj());
    if (!writeConcernParseStatus.isOK()) {
        return writeConcernParseStatus;
    }

    return MigrationSecondaryThrottleOptions::createWithWriteConcern(writeConcern);
}

StatusWith<WriteConcernOptions> WriteConcernOptions::extractWCFromCommand(
    const BSONObj& cmdObj, const std::string& dbName, const WriteConcernOptions& defaultWC) {
    WriteConcernOptions writeConcern = defaultWC;
    writeConcern.usedDefault = true;
    if (writeConcern.wNumNodes == 0 && writeConcern.wMode.empty()) {
        writeConcern.wNumNodes = 1;
    }

    BSONElement writeConcernElement;
    Status wcStatus = bsonExtractTypedField(cmdObj, "writeConcern", Object, &writeConcernElement);
    if (!wcStatus.isOK()) {
        if (wcStatus == ErrorCodes::NoSuchKey) {
            // Return default write concern if no write concern is given.
            return writeConcern;
        }
        return wcStatus;
    }

    BSONObj writeConcernObj = writeConcernElement.Obj();
    // Empty write concern is interpreted to default.
    if (writeConcernObj.isEmpty()) {
        return writeConcern;
    }

    wcStatus = writeConcern.parse(writeConcernObj);
    writeConcern.usedDefault = false;
    if (!wcStatus.isOK()) {
        return wcStatus;
    }

    return writeConcern;
}

BSONObj CommandHelpers::appendMajorityWriteConcern(const BSONObj& cmdObj) {
    WriteConcernOptions newWC = kMajorityWriteConcern;

    if (cmdObj.hasField(kWriteConcernField)) {
        auto wc = cmdObj.getField(kWriteConcernField);
        // The command has a writeConcern field and it's majority, so we can
        // return it as-is.
        if (wc["w"].ok() && wc["w"].str() == "majority") {
            return cmdObj;
        }

        if (wc["wtimeout"].ok()) {
            // They set a timeout, but aren't using majority WC. We want to use their
            // timeout along with majority WC.
            newWC = WriteConcernOptions(WriteConcernOptions::kMajority,
                                        WriteConcernOptions::SyncMode::UNSET,
                                        wc["wtimeout"].Number());
        }
    }

    // Append all original fields except the writeConcern field to the new command.
    BSONObjBuilder cmdObjWithWriteConcern;
    for (const auto& elem : cmdObj) {
        const auto name = elem.fieldNameStringData();
        if (name != "writeConcern" && !cmdObjWithWriteConcern.hasField(name)) {
            cmdObjWithWriteConcern.append(elem);
        }
    }

    // Finally, add the new write concern.
    cmdObjWithWriteConcern.append(kWriteConcernField, newWC.toBSON());
    return cmdObjWithWriteConcern.obj();
}

WriteConcernOptions MigrationSecondaryThrottleOptions::getWriteConcern() const {
    invariant(_secondaryThrottle != kOff);
    invariant(_writeConcernBSON);

    WriteConcernOptions writeConcern;
    fassertStatusOK(34414, writeConcern.parse(*_writeConcernBSON));

    return writeConcern;
}

Status validateWriteConcern(OperationContext* txn,
                            const WriteConcernOptions& writeConcern,
                            const std::string& dbName) {
    const bool isJournalEnabled = getGlobalServiceContext()->getGlobalStorageEngine()->isDurable();

    if (writeConcern.syncMode == WriteConcernOptions::SyncMode::JOURNAL && !isJournalEnabled) {
        return Status(ErrorCodes::BadValue,
                      "cannot use 'j' option when a host does not have journaling enabled");
    }

    const bool isConfigServer = serverGlobalParams.clusterRole == ClusterRole::ConfigServer;
    const bool isLocalDb(dbName == kLocalDB);
    const repl::ReplicationCoordinator::Mode replMode =
        repl::getGlobalReplicationCoordinator()->getReplicationMode();

    if (isConfigServer) {
        if (!writeConcern.validForConfigServers()) {
            return Status(
                ErrorCodes::BadValue,
                str::stream()
                    << "w:1 and w:'majority' are the only valid write concerns when writing to "
                       "config servers, got: "
                    << writeConcern.toBSON().toString());
        }

        if (replMode == repl::ReplicationCoordinator::modeReplSet &&
            // Allow writes performed within the server to have a write concern of { w: 1 }.
            // This is so commands have the option to skip waiting for replication if they are
            // holding locks (ex. addShardToZone). This also allows commands that perform
            // multiple writes to batch the wait at the end.
            !txn->getClient()->isInDirectClient() &&
            !isLocalDb && writeConcern.wMode.empty()) {
            invariant(writeConcern.wNumNodes == 1);
            return Status(
                ErrorCodes::BadValue,
                str::stream()
                    << "w: 'majority' is the only valid write concern when writing to config "
                       "server replica sets, got: "
                    << writeConcern.toBSON().toString());
        }
    }

    if (replMode == repl::ReplicationCoordinator::modeNone) {
        if (writeConcern.wNumNodes > 1) {
            return Status(ErrorCodes::BadValue, "cannot use 'w' > 1 when a host is not replicated");
        }
    }

    if (replMode != repl::ReplicationCoordinator::modeReplSet && !writeConcern.wMode.empty() &&
        writeConcern.wMode != WriteConcernOptions::kMajority) {
        return Status(ErrorCodes::BadValue,
                      string("cannot use non-majority 'w' mode ") + writeConcern.wMode +
                          " when a host is not a member of a replica set");
    }

    return Status::OK();
}

Status validateWriteConcern(const WriteConcernOptions& writeConcern, const std::string& dbName) {
    const bool isJournalEnabled = getGlobalServiceContext()->getGlobalStorageEngine()->isDurable();

    if (writeConcern.syncMode == WriteConcernOptions::JOURNAL && !isJournalEnabled) {
        return Status(ErrorCodes::BadValue,
                      "cannot use 'j' option when a host does not have journaling enabled");
    }

    const bool isConfigServer = serverGlobalParams.configsvr;
    const bool isLocalDb(dbName == kLocalDB);
    const repl::ReplicationCoordinator::Mode replMode =
        repl::getGlobalReplicationCoordinator()->getReplicationMode();

    if (isConfigServer) {
        if (!writeConcern.validForConfigServers()) {
            return Status(
                ErrorCodes::BadValue,
                str::stream()
                    << "w:1 and w:'majority' are the only valid write concerns when writing to "
                       "config servers, got: " << writeConcern.toBSON().toString());
        }
        if (serverGlobalParams.configsvrMode == CatalogManager::ConfigServerMode::CSRS &&
            replMode == repl::ReplicationCoordinator::modeReplSet && !isLocalDb &&
            writeConcern.wMode.empty()) {
            invariant(writeConcern.wNumNodes == 1);
            return Status(
                ErrorCodes::BadValue,
                str::stream()
                    << "w: 'majority' is the only valid write concern when writing to config "
                       "server replica sets, got: " << writeConcern.toBSON().toString());
        }
    }

    if (replMode == repl::ReplicationCoordinator::modeNone) {
        if (writeConcern.wNumNodes > 1) {
            return Status(ErrorCodes::BadValue, "cannot use 'w' > 1 when a host is not replicated");
        }
    }

    if (replMode != repl::ReplicationCoordinator::modeReplSet && !writeConcern.wMode.empty() &&
        writeConcern.wMode != WriteConcernOptions::kMajority) {
        return Status(ErrorCodes::BadValue,
                      string("cannot use non-majority 'w' mode ") + writeConcern.wMode +
                          " when a host is not a member of a replica set");
    }

    return Status::OK();
}

        bool run(const string& dbname, BSONObj& _cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
            LastError *le = lastError.disableForCommand();

            if ( le->nPrev != 1 ) {
                LastError::noError.appendSelf( result , false );
                le->appendSelfStatus( result );
            }
            else {
                le->appendSelf( result , false );
            }

            Client& c = cc();
            c.appendLastOp( result );

            result.appendNumber( "connectionId" , c.getConnectionId() ); // for sharding; also useful in general for debugging

            BSONObj cmdObj = _cmdObj;
            {
                BSONObj::iterator i(_cmdObj);
                i.next();
                if( !i.more() ) {
                    /* empty, use default */
                    BSONObj *def = getLastErrorDefault;
                    if( def )
                        cmdObj = *def;
                }
            }

            WriteConcernOptions writeConcern;
            Status status = writeConcern.parse( cmdObj );
            if ( !status.isOK() ) {
                result.append( "badGLE", cmdObj );
                errmsg = status.toString();
                return false;
            }

            WriteConcernResult res;
            status = waitForWriteConcern( cc(), writeConcern, &res );
            res.appendTo( &result );
            if ( status.code() == ErrorCodes::WriteConcernLegacyOK ) {
                result.append( "wnote", status.toString() );
                return true;
            }
            return appendCommandStatus( result, status );
        }

MigrationSecondaryThrottleOptions MigrationSecondaryThrottleOptions::createWithWriteConcern(
    const WriteConcernOptions& writeConcern) {
    // Optimize on write concern, which makes no difference
    if (writeConcern.wNumNodes <= 1 && writeConcern.wMode.empty()) {
        return MigrationSecondaryThrottleOptions(kOff, boost::none);
    }

    return MigrationSecondaryThrottleOptions(kOn, writeConcern.toBSON());
}

StatusWith<WriteConcernOptions> extractWriteConcern(const BSONObj& cmdObj,
                                                    const std::string& dbName) {
    // The default write concern if empty is w : 1
    // Specifying w : 0 is/was allowed, but is interpreted identically to w : 1
    WriteConcernOptions writeConcern =
        repl::getGlobalReplicationCoordinator()->getGetLastErrorDefault();
    if (writeConcern.wNumNodes == 0 && writeConcern.wMode.empty()) {
        writeConcern.wNumNodes = 1;
    }
    // Upgrade default write concern if necessary.
    addJournalSyncForWMajority(&writeConcern);

    BSONElement writeConcernElement;
    Status wcStatus = bsonExtractTypedField(cmdObj, "writeConcern", Object, &writeConcernElement);
    if (!wcStatus.isOK()) {
        if (wcStatus == ErrorCodes::NoSuchKey) {
            // Return default write concern if no write concern is given.
            return writeConcern;
        }
        return wcStatus;
    }

    BSONObj writeConcernObj = writeConcernElement.Obj();
    // Empty write concern is interpreted to default.
    if (writeConcernObj.isEmpty()) {
        return writeConcern;
    }

    wcStatus = writeConcern.parse(writeConcernObj);
    if (!wcStatus.isOK()) {
        return wcStatus;
    }

    wcStatus = validateWriteConcern(writeConcern, dbName);
    if (!wcStatus.isOK()) {
        return wcStatus;
    }

    // Upgrade parsed write concern if necessary.
    addJournalSyncForWMajority(&writeConcern);

    return writeConcern;
}

Status validateWriteConcern(OperationContext* txn,
                            const WriteConcernOptions& writeConcern,
                            StringData dbName) {
    if (writeConcern.syncMode == WriteConcernOptions::SyncMode::JOURNAL &&
        !txn->getServiceContext()->getGlobalStorageEngine()->isDurable()) {
        return Status(ErrorCodes::BadValue,
                      "cannot use 'j' option when a host does not have journaling enabled");
    }

    // Remote callers of the config server (as in callers making network calls, not the internal
    // logic) should never be making non-majority writes against the config server, because sharding
    // is not resilient against rollbacks of metadata writes.
    if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer &&
        dbName != NamespaceString::kLocalDb && !writeConcern.validForConfigServers()) {
        // The only cases where we allow non-majority writes are from within the config servers
        // themselves, because these wait for write concern explicitly.
        if (!txn->getClient()->isInDirectClient()) {
            return {ErrorCodes::BadValue,
                    str::stream() << "w:'majority' is the only valid write concern when writing "
                                     "to config servers, got: "
                                  << writeConcern.toBSON()};
        }
    }

    const auto replMode = repl::ReplicationCoordinator::get(txn)->getReplicationMode();

    if (replMode == repl::ReplicationCoordinator::modeNone && writeConcern.wNumNodes > 1) {
        return Status(ErrorCodes::BadValue, "cannot use 'w' > 1 when a host is not replicated");
    }

    if (replMode != repl::ReplicationCoordinator::modeReplSet && !writeConcern.wMode.empty() &&
        writeConcern.wMode != WriteConcernOptions::kMajority) {
        return Status(ErrorCodes::BadValue,
                      string("cannot use non-majority 'w' mode ") + writeConcern.wMode +
                          " when a host is not a member of a replica set");
    }

    return Status::OK();
}

StatusWith<WriteConcernOptions> ChunkMoveWriteConcernOptions::getEffectiveWriteConcern(
    OperationContext* opCtx, const MigrationSecondaryThrottleOptions& options) {
    auto secondaryThrottle = options.getSecondaryThrottle();
    if (secondaryThrottle == MigrationSecondaryThrottleOptions::kDefault) {
        if (opCtx->getServiceContext()->getStorageEngine()->supportsDocLocking()) {
            secondaryThrottle = MigrationSecondaryThrottleOptions::kOff;
        } else {
            secondaryThrottle = MigrationSecondaryThrottleOptions::kOn;
        }
    }

    if (secondaryThrottle == MigrationSecondaryThrottleOptions::kOff) {
        return kWriteConcernLocal;
    }

    WriteConcernOptions writeConcern;

    if (options.isWriteConcernSpecified()) {
        writeConcern = options.getWriteConcern();

        repl::ReplicationCoordinator* replCoordinator = repl::ReplicationCoordinator::get(opCtx);

        Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcern);
        if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
            return status;
        }
    } else {
        writeConcern = getDefaultWriteConcernForMigration(opCtx);
    }

    if (writeConcern.shouldWaitForOtherNodes() &&
        writeConcern.wTimeout == WriteConcernOptions::kNoTimeout) {
        // Don't allow no timeout
        writeConcern.wTimeout = durationCount<Milliseconds>(kDefaultWriteTimeoutForMigration);
    }

    return writeConcern;
}

StatusWith<ChunkMoveWriteConcernOptions> ChunkMoveWriteConcernOptions::initFromCommand(
    const BSONObj& cmdObj) {
    BSONObj secThrottleObj;
    WriteConcernOptions writeConcernOptions;

    Status status = writeConcernOptions.parseSecondaryThrottle(cmdObj, &secThrottleObj);
    if (!status.isOK()) {
        if (status.code() != ErrorCodes::WriteConcernNotDefined) {
            return status;
        }

        writeConcernOptions = getDefaultWriteConcernForMigration();
    } else {
        repl::ReplicationCoordinator* replCoordinator = repl::getGlobalReplicationCoordinator();

        if (replCoordinator->getReplicationMode() ==
                repl::ReplicationCoordinator::modeMasterSlave &&
            writeConcernOptions.shouldWaitForOtherNodes()) {
            warning() << "moveChunk cannot check if secondary throttle setting "
                      << writeConcernOptions.toBSON()
                      << " can be enforced in a master slave configuration";
        }

        Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcernOptions);
        if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
            return status;
        }
    }

    if (writeConcernOptions.shouldWaitForOtherNodes() &&
        writeConcernOptions.wTimeout == WriteConcernOptions::kNoTimeout) {
        // Don't allow no timeout
        writeConcernOptions.wTimeout = kDefaultWriteTimeoutForMigrationMs;
    }

    return ChunkMoveWriteConcernOptions(secThrottleObj, writeConcernOptions);
}

StatusWith<WriteConcernOptions> ChunkMoveWriteConcernOptions::getEffectiveWriteConcern(
    const MigrationSecondaryThrottleOptions& options) {
    if (options.getSecondaryThrottle() == MigrationSecondaryThrottleOptions::kOff) {
        return kWriteConcernLocal;
    }

    WriteConcernOptions writeConcern;

    if (options.isWriteConcernSpecified()) {
        writeConcern = options.getWriteConcern();

        repl::ReplicationCoordinator* replCoordinator = repl::getGlobalReplicationCoordinator();

        if (replCoordinator->getReplicationMode() ==
                repl::ReplicationCoordinator::modeMasterSlave &&
            writeConcern.shouldWaitForOtherNodes()) {
            warning() << "moveChunk cannot check if secondary throttle setting "
                      << writeConcern.toBSON()
                      << " can be enforced in a master slave configuration";
        }

        Status status = replCoordinator->checkIfWriteConcernCanBeSatisfied(writeConcern);
        if (!status.isOK() && status != ErrorCodes::NoReplicationEnabled) {
            return status;
        }
    } else {
        writeConcern = getDefaultWriteConcernForMigration();
    }

    if (writeConcern.shouldWaitForOtherNodes() &&
        writeConcern.wTimeout == WriteConcernOptions::kNoTimeout) {
        // Don't allow no timeout
        writeConcern.wTimeout = durationCount<Milliseconds>(kDefaultWriteTimeoutForMigration);
    }

    return writeConcern;
}

StatusWith<WriteConcernOptions> WriteConcernOptions::extractWCFromCommand(
    const BSONObj& cmdObj, const std::string& dbName, const WriteConcernOptions& defaultWC) {
    WriteConcernOptions writeConcern = defaultWC;
    writeConcern.usedDefault = true;
    if (writeConcern.wNumNodes == 0 && writeConcern.wMode.empty()) {
        writeConcern.wNumNodes = 1;
    }

    // Return the default write concern if no write concern is provided. We check for the existence
    // of the write concern field up front in order to avoid the expense of constructing an error
    // status in bsonExtractTypedField() below.
    if (!cmdObj.hasField(kWriteConcernField)) {
        return writeConcern;
    }

    BSONElement writeConcernElement;
    Status wcStatus =
        bsonExtractTypedField(cmdObj, kWriteConcernField, Object, &writeConcernElement);
    if (!wcStatus.isOK()) {
        return wcStatus;
    }

    BSONObj writeConcernObj = writeConcernElement.Obj();
    // Empty write concern is interpreted to default.
    if (writeConcernObj.isEmpty()) {
        return writeConcern;
    }

    wcStatus = writeConcern.parse(writeConcernObj);
    writeConcern.usedDefault = false;
    if (!wcStatus.isOK()) {
        return wcStatus;
    }

    return writeConcern;
}

StatusWith<bool> ShardingCatalogClientImpl::_updateConfigDocument(
    OperationContext* opCtx,
    const NamespaceString& nss,
    const BSONObj& query,
    const BSONObj& update,
    bool upsert,
    const WriteConcernOptions& writeConcern) {
    invariant(nss.db() == NamespaceString::kConfigDb);

    const BSONElement idField = query.getField("_id");
    invariant(!idField.eoo());

    BatchedCommandRequest request([&] {
        write_ops::Update updateOp(nss);
        updateOp.setUpdates({[&] {
            write_ops::UpdateOpEntry entry;
            entry.setQ(query);
            entry.setU(update);
            entry.setUpsert(upsert);
            entry.setMulti(false);
            return entry;
        }()});
        return updateOp;
    }());
    request.setWriteConcern(writeConcern.toBSON());

    auto configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
    auto response = configShard->runBatchWriteCommand(
        opCtx, Shard::kDefaultConfigCommandTimeout, request, Shard::RetryPolicy::kIdempotent);

    Status status = response.toStatus();
    if (!status.isOK()) {
        return status;
    }

    const auto nSelected = response.getN();
    invariant(nSelected == 0 || nSelected == 1);
    return (nSelected == 1);
}