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// @file syncclusterconnection.h
/*
* Copyright 2010 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/client/dbclientinterface.h"
#include "mongo/client/export_macros.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 MONGO_CLIENT_API 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 list<HostAndPort> &, double socketTimeout = 0);
SyncClusterConnection( 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( string& errmsg );
/**
* runs fsync on all servers
*/
bool fsync( string& errmsg );
// --- from DBClientInterface
virtual BSONObj findOne(const string &ns, const Query& query, const BSONObj *fieldsToReturn, int queryOptions);
virtual auto_ptr<DBClientCursor> query(const string &ns, Query query, int nToReturn, int nToSkip,
const BSONObj *fieldsToReturn, int queryOptions, int batchSize );
virtual auto_ptr<DBClientCursor> getMore( const string &ns, long long cursorId, int nToReturn, int options );
virtual void insert( const string &ns, BSONObj obj, int flags=0);
virtual void insert( const string &ns, const vector< BSONObj >& v, int flags=0);
virtual void remove( const string &ns , Query query, int flags );
virtual void update( const string &ns , Query query , BSONObj obj , int flags );
virtual bool call( Message &toSend, Message &response, bool assertOk , string * actualServer );
virtual void say( Message &toSend, bool isRetry = false , string * actualServer = 0 );
virtual void sayPiggyBack( Message &toSend );
virtual void killCursor( long long cursorID );
virtual string getServerAddress() const { return _address; }
virtual bool isFailed() const { return false; }
virtual bool isStillConnected();
virtual 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; }
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 );
string _toString() const;
bool _commandOnActive(const string &dbname, const BSONObj& cmd, BSONObj &info, int options=0);
auto_ptr<DBClientCursor> _queryOnActive(const string &ns, Query query, int nToReturn, int nToSkip,
const BSONObj *fieldsToReturn, int queryOptions, int batchSize );
int _lockType( const string& name );
void _checkLast();
void _connect( const std::string& host );
string _address;
vector<string> _connAddresses;
vector<DBClientConnection*> _conns;
vector<BSONObj> _lastErrors;
// Optionally attached by user
scoped_ptr<QueryHandler> _customQueryHandler;
mongo::mutex _mutex;
map<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 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 auto_ptr on failure.
*/
virtual auto_ptr<DBClientCursor> handleQuery( const vector<string>& hosts,
const string &ns,
Query query,
int nToReturn,
int nToSkip,
const BSONObj *fieldsToReturn,
int queryOptions,
int batchSize ) = 0;
};
class MONGO_CLIENT_API UpdateNotTheSame : public UserException {
public:
UpdateNotTheSame( int code , const string& msg , const vector<string>& addrs , const vector<BSONObj>& lastErrors )
: UserException( code , msg ) , _addrs( addrs ) , _lastErrors( lastErrors ) {
verify( _addrs.size() == _lastErrors.size() );
}
virtual ~UpdateNotTheSame() throw() {
}
unsigned size() const {
return _addrs.size();
}
pair<string,BSONObj> operator[](unsigned i) const {
return make_pair( _addrs[i] , _lastErrors[i] );
}
private:
vector<string> _addrs;
vector<BSONObj> _lastErrors;
};
};
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