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/** @file oplogreader.h */
/**
* Copyright (C) 2012 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/client/constants.h"
#include "mongo/client/dbclientcursor.h"
#include "mongo/util/net/hostandport.h"
#include "mongo/util/time_support.h"
namespace mongo {
class OperationContext;
namespace repl {
class ReplicationCoordinator;
class OpTime;
// {"$natural": -1 }
extern const BSONObj reverseNaturalObj;
/**
* Authenticates conn using the server's cluster-membership credentials.
*
* Returns true on successful authentication.
*/
bool replAuthenticate(DBClientBase* conn);
/* started abstracting out the querying of the primary/master's oplog
still fairly awkward but a start.
*/
class OplogReader {
private:
std::shared_ptr<DBClientConnection> _conn;
std::shared_ptr<DBClientCursor> cursor;
int _tailingQueryOptions;
// If _conn was actively connected, _host represents the current HostAndPort of the
// connection.
HostAndPort _host;
public:
OplogReader();
~OplogReader() {}
void resetCursor() {
cursor.reset();
}
void resetConnection() {
cursor.reset();
_conn.reset();
_host = HostAndPort();
}
DBClientConnection* conn() {
return _conn.get();
}
BSONObj findOne(const char* ns, const Query& q) {
return conn()->findOne(ns, q, 0, QueryOption_SlaveOk);
}
BSONObj getLastOp(const std::string& ns) {
return findOne(ns.c_str(), Query().sort(reverseNaturalObj));
}
/* SO_TIMEOUT (send/recv time out) for our DBClientConnections */
static const Seconds kSocketTimeout;
/* ok to call if already connected */
bool connect(const HostAndPort& host);
void tailCheck();
bool haveCursor() {
return cursor.get() != 0;
}
void query(const char* ns, Query query, int nToReturn, int nToSkip, const BSONObj* fields = 0);
void tailingQuery(const char* ns, const BSONObj& query);
void tailingQueryGTE(const char* ns, Timestamp t);
bool more() {
uassert(15910, "Doesn't have cursor for reading oplog", cursor.get());
return cursor->more();
}
bool moreInCurrentBatch() {
uassert(15911, "Doesn't have cursor for reading oplog", cursor.get());
return cursor->moreInCurrentBatch();
}
int currentBatchMessageSize() {
if (NULL == cursor->getMessage())
return 0;
return cursor->getMessage()->size();
}
BSONObj nextSafe() {
return cursor->nextSafe();
}
BSONObj next() {
return cursor->next();
}
// master/slave only
void peek(std::vector<BSONObj>& v, int n) {
if (cursor.get())
cursor->peek(v, n);
}
// master/slave only
void putBack(BSONObj op) {
cursor->putBack(op);
}
HostAndPort getHost() const;
/**
* Connects this OplogReader to a valid sync source, using the provided lastOpTimeFetched
* and ReplicationCoordinator objects.
* If this function fails to connect to a sync source that is viable, this OplogReader
* is left unconnected, where this->conn() equals NULL.
* In the process of connecting, this function may add items to the repl coordinator's
* sync source blacklist.
* This function may throw DB exceptions.
*/
void connectToSyncSource(OperationContext* txn,
const OpTime& lastOpTimeFetched,
const OpTime& requiredOpTime,
ReplicationCoordinator* replCoord);
private:
/**
* Checks query response for required optime.
*/
Status _compareRequiredOpTimeWithQueryResponse(const OpTime& requiredOpTime);
};
} // namespace repl
} // namespace mongo
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