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// @file syncclusterconnection.h
/*
* Copyright 2010 10gen 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.
*/
#pragma once
#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/client/dbclientinterface.h"
#include "mongo/util/concurrency/mutex.h"
namespace mongo {
/**
* This is a connection to a cluster of servers that operate as one
* for super high durability.
*
* Write operations are two-phase. First, all nodes are asked to fsync. If successful
* everywhere, the write is sent everywhere and then followed by an fsync. There is no
* rollback if a problem occurs during the second phase. Naturally, with all these fsyncs,
* these operations will be quite slow -- use sparingly.
*
* Read operations are sent to a single random node.
*
* The class checks if a command is read or write style, and sends to a single
* node if a read lock command and to all in two phases with a write style command.
*/
class SyncClusterConnection : public DBClientBase {
public:
using DBClientBase::query;
using DBClientBase::update;
using DBClientBase::remove;
class QueryHandler;
/**
* @param commaSeparated should be 3 hosts comma separated
*/
SyncClusterConnection( const std::list<HostAndPort> &, double socketTimeout = 0);
SyncClusterConnection( std::string commaSeparated, double socketTimeout = 0);
SyncClusterConnection( const std::string& a,
const std::string& b,
const std::string& c,
double socketTimeout = 0 );
~SyncClusterConnection();
/**
* @return true if all servers are up and ready for writes
*/
bool prepare( std::string& errmsg );
// --- from DBClientInterface
virtual BSONObj findOne(const std::string &ns, const Query& query, const BSONObj *fieldsToReturn, int queryOptions);
virtual std::unique_ptr<DBClientCursor> query(const std::string &ns, Query query, int nToReturn, int nToSkip,
const BSONObj *fieldsToReturn, int queryOptions, int batchSize );
virtual std::unique_ptr<DBClientCursor> getMore( const std::string &ns, long long cursorId, int nToReturn, int options );
virtual void insert( const std::string &ns, BSONObj obj, int flags=0);
virtual void insert( const std::string &ns, const std::vector< BSONObj >& v, int flags=0);
virtual void remove( const std::string &ns , Query query, int flags );
virtual void update( const std::string &ns , Query query , BSONObj obj , int flags );
virtual bool call( Message &toSend, Message &response, bool assertOk , std::string * actualServer );
virtual void say( Message &toSend, bool isRetry = false , std::string * actualServer = 0 );
virtual void sayPiggyBack( Message &toSend );
virtual void killCursor( long long cursorID );
virtual std::string getServerAddress() const { return _address; }
virtual bool isFailed() const { return false; }
virtual bool isStillConnected();
virtual std::string toString() const { return _toString(); }
virtual BSONObj getLastErrorDetailed(const std::string& db,
bool fsync=false,
bool j=false,
int w=0,
int wtimeout=0);
virtual BSONObj getLastErrorDetailed(bool fsync=false, bool j=false, int w=0, int wtimeout=0);
virtual bool callRead( Message& toSend , Message& response );
virtual ConnectionString::ConnectionType type() const { return ConnectionString::SYNC; }
void setAllSoTimeouts( double socketTimeout );
double getSoTimeout() const { return _socketTimeout; }
virtual bool lazySupported() const { return false; }
// This override of runCommand intentionally calls findOne to construct a legacy
// OP_QUERY command. The reason for this is that delicate logic for targeting/locking
// config servers is in SyncClusterConnection::findOne, and refactoring that logic
// is both risky and of dubious value as we move to config server replica sets (CSRS).
virtual bool runCommand(const std::string& dbname,
const BSONObj& cmd,
BSONObj& info,
int options) final;
virtual void setRunCommandHook(DBClientWithCommands::RunCommandHookFunc func);
virtual void setPostRunCommandHook(DBClientWithCommands::PostRunCommandHookFunc func);
/**
* Allow custom query processing through an external (e.g. mongos-only) service.
*
* Takes ownership of attached handler.
*/
void attachQueryHandler( QueryHandler* handler );
protected:
virtual void _auth(const BSONObj& params);
private:
SyncClusterConnection( SyncClusterConnection& prev, double socketTimeout = 0 );
std::string _toString() const;
bool _commandOnActive(const std::string &dbname, const BSONObj& cmd, BSONObj &info, int options=0);
std::unique_ptr<DBClientCursor> _queryOnActive(const std::string &ns, Query query, int nToReturn, int nToSkip,
const BSONObj *fieldsToReturn, int queryOptions, int batchSize );
int _lockType( const std::string& name );
void _checkLast();
void _connect( const std::string& host );
std::string _address;
std::vector<std::string> _connAddresses;
std::vector<DBClientConnection*> _conns;
std::vector<BSONObj> _lastErrors;
// Optionally attached by user
std::unique_ptr<QueryHandler> _customQueryHandler;
mongo::mutex _mutex;
std::map<std::string,int> _lockTypes;
// End mutex
double _socketTimeout;
};
/**
* Interface for custom query processing for the SCC.
* Allows plugging different host query behaviors for different types of queries.
*/
class SyncClusterConnection::QueryHandler {
public:
virtual ~QueryHandler() {};
/**
* Returns true if the query can be processed using this handler.
*/
virtual bool canHandleQuery( const std::string& ns, Query query ) = 0;
/**
* Returns a cursor on one of the hosts with the desired results for the query.
* May throw or return an empty unique_ptr on failure.
*/
virtual std::unique_ptr<DBClientCursor> handleQuery( const std::vector<std::string>& hosts,
const std::string &ns,
Query query,
int nToReturn,
int nToSkip,
const BSONObj *fieldsToReturn,
int queryOptions,
int batchSize ) = 0;
};
class UpdateNotTheSame : public UserException {
public:
UpdateNotTheSame( int code , const std::string& msg , const std::vector<std::string>& addrs , const std::vector<BSONObj>& lastErrors )
: UserException( code , msg ) , _addrs( addrs ) , _lastErrors( lastErrors ) {
verify( _addrs.size() == _lastErrors.size() );
}
virtual ~UpdateNotTheSame() throw() {
}
unsigned size() const {
return _addrs.size();
}
std::pair<std::string,BSONObj> operator[](unsigned i) const {
return std::make_pair( _addrs[i] , _lastErrors[i] );
}
private:
std::vector<std::string> _addrs;
std::vector<BSONObj> _lastErrors;
};
};
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