mongodb/tools/bridge.cpp

// bridge.cpp

/**
 *    Copyright (C) 2008 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/>.
 */

#include "stdafx.h"
#include "../util/message.h"
#include "../client/dbclient.h"

using namespace mongo;
using namespace std;

int port = 0;
string destUri;

class Forwarder {
public:
    Forwarder( MessagingPort &mp ) : mp_( mp ) {
    }
    void operator()() const {
        DBClientConnection dest;
        string errmsg;
        while( !dest.connect( destUri, errmsg ) )
            sleepmillis( 500 );
        Message m;
        while( 1 ) {
            m.reset();
            if ( !mp_.recv( m ) ) {
                cout << "end connection " << mp_.farEnd.toString() << endl;
                mp_.shutdown();
                break;
            }

            int oldId = m.data->id;
            if ( m.data->operation() == dbQuery || m.data->operation() == dbMsg || m.data->operation() == dbGetMore ) {
                Message response;
                dest.port().call( m, response );
                mp_.reply( m, response, oldId );
            } else {
                dest.port().say( m, oldId );
            }
        }
    }
private:
    MessagingPort &mp_;
};

class MyListener : public Listener {
public:
    MyListener( int port ) : Listener( port ) {}
    virtual void accepted(MessagingPort *mp) {
        Forwarder f( *mp );
        boost::thread t( f );
    }
};

void helpExit() {
    cout << "usage mongobridge --port <port> --dest <destUri>" << endl;
    cout << "    port: port to listen for mongo messages" << endl;
    cout << "    destUri: uri of remote mongod instance" << endl;
    ::exit( -1 );
}

void check( bool b ) {
    if ( !b )
        helpExit();
}

int main( int argc, char **argv ) {

    check( argc == 5 );

    for( int i = 1; i < 5; ++i ) {
        check( i % 2 != 0 );
        if ( strcmp( argv[ i ], "--port" ) == 0 ) {
            port = strtol( argv[ ++i ], 0, 10 );
        } else if ( strcmp( argv[ i ], "--dest" ) == 0 ) {
            destUri = argv[ ++i ];
        } else {
            check( false );
        }
    }
    check( port != 0 && !destUri.empty() );

    MyListener l( port );
    l.init();
    l.listen();

    return 0;
}