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/**
* Copyright (C) 2015 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 "mongo/platform/basic.h"
#include <vector>
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/lasterror.h"
#include "mongo/s/client/dbclient_multi_command.h"
#include "mongo/s/cluster_last_error_info.h"
#include "mongo/s/dbclient_shard_resolver.h"
#include "mongo/s/write_ops/batch_downconvert.h"
namespace mongo {
namespace {
class GetLastErrorCmd : public Command {
public:
GetLastErrorCmd() : Command("getLastError", false, "getlasterror") {}
virtual bool isWriteCommandForConfigServer() const {
return false;
}
virtual bool slaveOk() const {
return true;
}
virtual void help(std::stringstream& help) const {
help << "check for an error on the last command executed";
}
virtual void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector<Privilege>* out) {
// No auth required for getlasterror
}
virtual bool run(OperationContext* txn,
const std::string& dbname,
BSONObj& cmdObj,
int options,
std::string& errmsg,
BSONObjBuilder& result) {
// Mongos GLE - finicky.
//
// To emulate mongod, we first append any write errors we had, then try to append
// write concern error if there was no write error. We need to contact the previous
// shards regardless to maintain 2.4 behavior.
//
// If there are any unexpected or connectivity errors when calling GLE, fail the
// command.
//
// Finally, report the write concern errors IF we don't already have an error.
// If we only get one write concern error back, report that, otherwise report an
// aggregated error.
//
// TODO: Do we need to contact the prev shards regardless - do we care that much
// about 2.4 behavior?
//
LastError* le = &LastError::get(cc());
le->disable();
// Write commands always have the error stored in the mongos last error
bool errorOccurred = false;
if (le->getNPrev() == 1) {
errorOccurred = le->appendSelf(result, false);
}
// For compatibility with 2.4 sharded GLE, we always enforce the write concern
// across all shards.
const HostOpTimeMap hostOpTimes(ClusterLastErrorInfo::get(cc()).getPrevHostOpTimes());
HostOpTimeMap resolvedHostOpTimes;
Status status(Status::OK());
for (HostOpTimeMap::const_iterator it = hostOpTimes.begin(); it != hostOpTimes.end();
++it) {
const ConnectionString& shardEndpoint = it->first;
const HostOpTime& hot = it->second;
ConnectionString resolvedHost;
status = DBClientShardResolver::findMaster(shardEndpoint, &resolvedHost);
if (!status.isOK()) {
break;
}
resolvedHostOpTimes[resolvedHost] = hot;
}
DBClientMultiCommand dispatcher;
std::vector<LegacyWCResponse> wcResponses;
if (status.isOK()) {
status = enforceLegacyWriteConcern(
&dispatcher, dbname, cmdObj, resolvedHostOpTimes, &wcResponses);
}
// Don't forget about our last hosts, reset the client info
ClusterLastErrorInfo::get(cc()).disableForCommand();
// We're now done contacting all remote servers, just report results
if (!status.isOK()) {
// Return immediately if we failed to contact a shard, unexpected GLE issue
// Can't return code, since it may have been set above (2.4 compatibility)
result.append("errmsg", status.reason());
return false;
}
// Go through all the write concern responses and find errors
BSONArrayBuilder shards;
BSONObjBuilder shardRawGLE;
BSONArrayBuilder errors;
BSONArrayBuilder errorRawGLE;
int numWCErrors = 0;
const LegacyWCResponse* lastErrResponse = NULL;
for (std::vector<LegacyWCResponse>::const_iterator it = wcResponses.begin();
it != wcResponses.end();
++it) {
const LegacyWCResponse& wcResponse = *it;
shards.append(wcResponse.shardHost);
shardRawGLE.append(wcResponse.shardHost, wcResponse.gleResponse);
if (!wcResponse.errToReport.empty()) {
numWCErrors++;
lastErrResponse = &wcResponse;
errors.append(wcResponse.errToReport);
errorRawGLE.append(wcResponse.gleResponse);
}
}
// Always report what we found to match 2.4 behavior and for debugging
if (wcResponses.size() == 1u) {
result.append("singleShard", wcResponses.front().shardHost);
} else {
result.append("shards", shards.arr());
result.append("shardRawGLE", shardRawGLE.obj());
}
// Suppress write concern errors if a write error occurred, to match mongod behavior
if (errorOccurred || numWCErrors == 0) {
// Still need to return err
if (!errorOccurred) {
result.appendNull("err");
}
return true;
}
if (numWCErrors == 1) {
// Return the single write concern error we found, err should be set or not
// from gle response
result.appendElements(lastErrResponse->gleResponse);
return lastErrResponse->gleResponse["ok"].trueValue();
} else {
// Return a generic combined WC error message
result.append("errs", errors.arr());
result.append("errObjects", errorRawGLE.arr());
// Need to always return err
result.appendNull("err");
return appendCommandStatus(
result,
Status(ErrorCodes::WriteConcernFailed, "multiple write concern errors occurred"));
}
}
} cmdGetLastError;
} // namespace
} // namespace mongo
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