From 8a8ee2579878473e18e6d311bcb46dc90936328d Mon Sep 17 00:00:00 2001 From: matt dannenberg Date: Fri, 24 Apr 2015 10:49:59 -0400 Subject: SERVER-18253 create VoteRequester Scatter-Gather Algorithm to conduct new style elections --- src/mongo/db/repl/vote_requester.h | 123 +++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 src/mongo/db/repl/vote_requester.h (limited to 'src/mongo/db/repl/vote_requester.h') diff --git a/src/mongo/db/repl/vote_requester.h b/src/mongo/db/repl/vote_requester.h new file mode 100644 index 00000000000..72c4f90c3f7 --- /dev/null +++ b/src/mongo/db/repl/vote_requester.h @@ -0,0 +1,123 @@ +/** + * 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 . + * + * 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. + */ + +#pragma once + +#include +#include + +#include "mongo/base/disallow_copying.h" +#include "mongo/bson/timestamp.h" +#include "mongo/db/repl/optime.h" +#include "mongo/db/repl/replica_set_config.h" +#include "mongo/db/repl/replication_executor.h" +#include "mongo/db/repl/scatter_gather_algorithm.h" +#include "mongo/stdx/functional.h" + +namespace mongo { + + class Status; + +namespace repl { + + class ScatterGatherRunner; + class ReplSetDeclareRequestVotesArgs; + + class VoteRequester { + MONGO_DISALLOW_COPYING(VoteRequester); + public: + + class Algorithm : public ScatterGatherAlgorithm { + public: + Algorithm(const ReplicaSetConfig& rsConfig, + long long candidateId, + long long term, + OpTime lastOplogEntry); + virtual ~Algorithm(); + virtual std::vector getRequests() const; + virtual void processResponse( + const ReplicationExecutor::RemoteCommandRequest& request, + const ResponseStatus& response); + virtual bool hasReceivedSufficientResponses() const; + + /** + * Returns BadValue if the term for which we are running is statel, IllegalOperation if + * insufficient votes are received, and Status::OK if we've won the election. + * + * It is invalid to call this before hasReceivedSufficeintResponses returns true. + */ + Status getStatus() const { return _status; } + + private: + const ReplicaSetConfig _rsConfig; + const long long _candidateId; + const long long _term; + const OpTime _lastOplogEntry; + std::vector _targets; + bool _failed = false; + long long _responsesProcessed = 0; + long long _votes = 1; + Status _status = Status::OK(); + }; + + VoteRequester(); + virtual ~VoteRequester(); + + /** + * Begins the process of sending replSetRequestVotes commands to all non-DOWN nodes + * in currentConfig, in attempt to receive sufficient votes to win the election. + * + * evh can be used to schedule a callback when the process is complete. + * This function must be run in the executor, as it must be synchronous with the command + * callbacks that it schedules. + * If this function returns Status::OK(), evh is then guaranteed to be signaled. + **/ + StatusWith start( + ReplicationExecutor* executor, + const ReplicaSetConfig& rsConfig, + long long candidateId, + long long term, + OpTime lastOplogEntry, + const stdx::function& onCompletion = stdx::function()); + + /** + * Informs the VoteRequester to cancel further processing. The "executor" + * argument must point to the same executor passed to "start()". + * + * Like start(), this method must run in the executor context. + */ + void cancel(ReplicationExecutor* executor); + + private: + std::unique_ptr _algorithm; + std::unique_ptr _runner; + bool _isCanceled = false; + }; + +} // namespace repl +} // namespace mongo -- cgit v1.2.1