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/**
* Copyright 2014 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
#include "mongo/platform/basic.h"
#include "mongo/db/repl/freshness_checker.h"
#include "mongo/base/status.h"
#include "mongo/bson/timestamp.h"
#include "mongo/db/repl/member_heartbeat_data.h"
#include "mongo/db/repl/replica_set_config.h"
#include "mongo/db/repl/replication_executor.h"
#include "mongo/db/repl/scatter_gather_runner.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/util/log.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace repl {
FreshnessChecker::Algorithm::Algorithm(
Timestamp lastOpTimeApplied,
const ReplicaSetConfig& rsConfig,
int selfIndex,
const std::vector<HostAndPort>& targets) :
_responsesProcessed(0),
_failedVoterResponses(0),
_lastOpTimeApplied(lastOpTimeApplied),
_rsConfig(rsConfig),
_selfIndex(selfIndex),
_targets(targets),
_votingTargets(0),
_losableVoters(0),
_myVote(0),
_abortReason(None) {
// Count voting targets (since the targets could be a subset of members).
for (std::vector<HostAndPort>::const_iterator it = _targets.begin();
it != _targets.end();
++it) {
const MemberConfig* member = _rsConfig.findMemberByHostAndPort(*it);
if (member && member->isVoter())
++_votingTargets;
}
_myVote = _rsConfig.getMemberAt(_selfIndex).isVoter() ? 1 : 0;
_losableVoters = std::max(0,
((_votingTargets + _myVote) - _rsConfig.getMajorityVoteCount()));
}
FreshnessChecker::Algorithm::~Algorithm() {}
std::vector<RemoteCommandRequest>
FreshnessChecker::Algorithm::getRequests() const {
const MemberConfig& selfConfig = _rsConfig.getMemberAt(_selfIndex);
// gather all not-down nodes, get their fullnames(or hostandport's)
// schedule fresh command for each node
BSONObjBuilder freshCmdBuilder;
freshCmdBuilder.append("replSetFresh", 1);
freshCmdBuilder.append("set", _rsConfig.getReplSetName());
freshCmdBuilder.append("opTime", Date_t::fromMillisSinceEpoch(_lastOpTimeApplied.asLL()));
freshCmdBuilder.append("who", selfConfig.getHostAndPort().toString());
freshCmdBuilder.appendIntOrLL("cfgver", _rsConfig.getConfigVersion());
freshCmdBuilder.append("id", selfConfig.getId());
const BSONObj replSetFreshCmd = freshCmdBuilder.obj();
std::vector<RemoteCommandRequest> requests;
for (std::vector<HostAndPort>::const_iterator it = _targets.begin();
it != _targets.end();
++it) {
invariant(*it != selfConfig.getHostAndPort());
requests.push_back(RemoteCommandRequest(
*it,
"admin",
replSetFreshCmd,
Milliseconds(30*1000))); // trying to match current Socket timeout
}
return requests;
}
bool FreshnessChecker::Algorithm::hadTooManyFailedVoterResponses() const {
const bool tooManyLostVoters = (_failedVoterResponses > _losableVoters);
LOG(3) << "hadTooManyFailedVoterResponses(" << tooManyLostVoters << ") = "
<< _failedVoterResponses << " failed responses <"
<< " (" << _votingTargets << " total voters - "
<< _rsConfig.getMajorityVoteCount() << " majority voters - me ("
<< _myVote << ")) -- losableVotes: " << _losableVoters;
return tooManyLostVoters;
}
bool FreshnessChecker::Algorithm::_isVotingMember(const HostAndPort hap) const {
const MemberConfig* member = _rsConfig.findMemberByHostAndPort(hap);
invariant(member);
return member->isVoter();
}
void FreshnessChecker::Algorithm::processResponse(
const RemoteCommandRequest& request,
const ResponseStatus& response) {
++_responsesProcessed;
bool votingMember = _isVotingMember(request.target);
Status status = Status::OK();
if (!response.isOK() ||
!((status = getStatusFromCommandResult(response.getValue().data)).isOK())) {
if (votingMember) {
++_failedVoterResponses;
if (hadTooManyFailedVoterResponses()) {
_abortReason = QuorumUnreachable;
}
}
if (!response.isOK()) { // network/executor error
LOG(2) << "FreshnessChecker: Got failed response from " << request.target;
}
else { // command error, like unauth
LOG(2) << "FreshnessChecker: Got error response from " << request.target
<< " :" << status;
}
return;
}
const BSONObj res = response.getValue().data;
LOG(2) << "FreshnessChecker: Got response from " << request.target
<< " of " << res;
if (res["fresher"].trueValue()) {
log() << "not electing self, we are not freshest";
_abortReason = FresherNodeFound;
return;
}
if (res["opTime"].type() != mongo::Date) {
error() << "wrong type for opTime argument in replSetFresh response: " <<
typeName(res["opTime"].type());
_abortReason = FresherNodeFound;
return;
}
Timestamp remoteTime(res["opTime"].date());
if (remoteTime == _lastOpTimeApplied) {
_abortReason = FreshnessTie;
}
if (remoteTime > _lastOpTimeApplied) {
// something really wrong (rogue command?)
_abortReason = FresherNodeFound;
return;
}
if (res["veto"].trueValue()) {
BSONElement msg = res["errmsg"];
if (msg.type() == String) {
log() << "not electing self, " << request.target.toString() <<
" would veto with '" << msg.String() << "'";
}
else {
log() << "not electing self, " << request.target.toString() <<
" would veto";
}
_abortReason = FresherNodeFound;
return;
}
}
bool FreshnessChecker::Algorithm::hasReceivedSufficientResponses() const {
return (_abortReason != None && _abortReason != FreshnessTie) ||
(_responsesProcessed == static_cast<int>(_targets.size()));
}
FreshnessChecker::ElectionAbortReason FreshnessChecker::Algorithm::shouldAbortElection() const {
return _abortReason;
}
FreshnessChecker::ElectionAbortReason FreshnessChecker::shouldAbortElection() const {
return _algorithm->shouldAbortElection();
}
long long FreshnessChecker::getOriginalConfigVersion() const {
return _originalConfigVersion;
}
FreshnessChecker::FreshnessChecker() : _isCanceled(false) {}
FreshnessChecker::~FreshnessChecker() {}
StatusWith<ReplicationExecutor::EventHandle> FreshnessChecker::start(
ReplicationExecutor* executor,
const Timestamp& lastOpTimeApplied,
const ReplicaSetConfig& currentConfig,
int selfIndex,
const std::vector<HostAndPort>& targets,
const stdx::function<void ()>& onCompletion) {
_originalConfigVersion = currentConfig.getConfigVersion();
_algorithm.reset(new Algorithm(lastOpTimeApplied, currentConfig, selfIndex, targets));
_runner.reset(new ScatterGatherRunner(_algorithm.get()));
return _runner->start(executor, onCompletion);
}
void FreshnessChecker::cancel(ReplicationExecutor* executor) {
_isCanceled = true;
_runner->cancel(executor);
}
} // namespace repl
} // namespace mongo
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