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/**
* Copyright (C) 2017 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <boost/none_t.hpp>
#include "mongo/platform/basic.h"
#include "mongo/s/client/rs_local_client.h"
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/db/curop.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/repl/repl_client_info.h"
#include "mongo/db/repl/repl_set_config.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/rpc/unique_message.h"
#include "mongo/s/client/shard.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
void RSLocalClient::_updateLastOpTimeFromClient(OperationContext* opCtx,
const repl::OpTime& previousOpTimeOnClient) {
const auto lastOpTimeFromClient =
repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
if (lastOpTimeFromClient.isNull() || lastOpTimeFromClient == previousOpTimeOnClient) {
return;
}
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (lastOpTimeFromClient >= _lastOpTime) {
// It's always possible for lastOpTimeFromClient to be less than _lastOpTime if another
// thread started and completed a write through this ShardLocal (updating _lastOpTime)
// after this operation had completed its write but before it got here.
_lastOpTime = lastOpTimeFromClient;
}
}
repl::OpTime RSLocalClient::_getLastOpTime() {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _lastOpTime;
}
StatusWith<Shard::CommandResponse> RSLocalClient::runCommandOnce(OperationContext* opCtx,
const std::string& dbName,
const BSONObj& cmdObj) {
const auto currentOpTimeFromClient =
repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
ON_BLOCK_EXIT([this, &opCtx, ¤tOpTimeFromClient] {
_updateLastOpTimeFromClient(opCtx, currentOpTimeFromClient);
});
try {
DBDirectClient client(opCtx);
rpc::UniqueReply commandResponse =
client.runCommand(OpMsgRequest::fromDBAndBody(dbName, cmdObj));
auto result = commandResponse->getCommandReply().getOwned();
return Shard::CommandResponse(boost::none,
result,
commandResponse->getMetadata().getOwned(),
getStatusFromCommandResult(result),
getWriteConcernStatusFromCommandResult(result));
} catch (const DBException& ex) {
return ex.toStatus();
}
}
StatusWith<Shard::QueryResponse> RSLocalClient::queryOnce(
OperationContext* opCtx,
const ReadPreferenceSetting& readPref,
const repl::ReadConcernLevel& readConcernLevel,
const NamespaceString& nss,
const BSONObj& query,
const BSONObj& sort,
boost::optional<long long> limit) {
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
if (readConcernLevel == repl::ReadConcernLevel::kMajorityReadConcern) {
// Set up operation context with majority read snapshot so correct optime can be retrieved.
opCtx->recoveryUnit()->setTimestampReadSource(RecoveryUnit::ReadSource::kMajorityCommitted);
Status status = opCtx->recoveryUnit()->obtainMajorityCommittedSnapshot();
// Wait for any writes performed by this ShardLocal instance to be committed and visible.
Status readConcernStatus = replCoord->waitUntilOpTimeForRead(
opCtx, repl::ReadConcernArgs{_getLastOpTime(), readConcernLevel});
if (!readConcernStatus.isOK()) {
return readConcernStatus;
}
// Inform the storage engine to read from the committed snapshot for the rest of this
// operation.
status = opCtx->recoveryUnit()->obtainMajorityCommittedSnapshot();
if (!status.isOK()) {
return status;
}
} else {
invariant(readConcernLevel == repl::ReadConcernLevel::kLocalReadConcern);
}
DBDirectClient client(opCtx);
Query fullQuery(query);
if (!sort.isEmpty()) {
fullQuery.sort(sort);
}
fullQuery.readPref(readPref.pref, BSONArray());
try {
std::unique_ptr<DBClientCursor> cursor =
client.query(nss.ns().c_str(), fullQuery, limit.get_value_or(0));
if (!cursor) {
return {ErrorCodes::OperationFailed,
str::stream() << "Failed to establish a cursor for reading " << nss.ns()
<< " from local storage"};
}
std::vector<BSONObj> documentVector;
while (cursor->more()) {
BSONObj document = cursor->nextSafe().getOwned();
documentVector.push_back(std::move(document));
}
return Shard::QueryResponse{std::move(documentVector),
replCoord->getCurrentCommittedSnapshotOpTime()};
} catch (const DBException& ex) {
return ex.toStatus();
}
}
} // namespace mongo
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