C++ Shard类代码示例

    Shard * Shard::split( const BSONObj& m ){
        uassert( "can't split as shard that doesn't have a manager" , _manager );
        
        log(1) << " before split on: "  << m << "\n"
               << "\t self  : " << toString() << endl;

        uassert( "locking namespace on server failed" , lockNamespaceOnServer( getServer() , _ns ) );

        Shard * s = new Shard( _manager );
        s->_ns = _ns;
        s->_server = _server;
        s->_min = m.getOwned();
        s->_max = _max;
        
        s->_markModified();
        _markModified();
        
        _manager->_shards.push_back( s );
        
        _max = m.getOwned(); 
        
        log(1) << " after split:\n" 
               << "\t left : " << toString() << "\n" 
               << "\t right: "<< s->toString() << endl;
        
        
        _manager->save();
        
        return s;
    }

    bool CmdAuthenticate::getUserObj(const string& dbname, const string& user, BSONObj& userObj, string& pwd) {
        if (user == internalSecurity.user) {
            uassert(15890, "key file must be used to log in with internal user",
                    !cmdLine.keyFile.empty());
            pwd = internalSecurity.pwd;
        }
        else {
            string systemUsers = dbname + ".system.users";
            DBConfigPtr config = grid.getDBConfig( systemUsers );
            Shard s = config->getShard( systemUsers );

            static BSONObj userPattern = BSON("user" << 1);

            scoped_ptr<ScopedDbConnection> conn(
                    ScopedDbConnection::getInternalScopedDbConnection( s.getConnString(), 30.0 ) );
            OCCASIONALLY conn->get()->ensureIndex(systemUsers, userPattern, false, "user_1");
            {
                BSONObjBuilder b;
                b << "user" << user;
                BSONObj query = b.done();
                userObj = conn->get()->findOne(systemUsers, query, 0, QueryOption_SlaveOk);
                if( userObj.isEmpty() ) {
                    log() << "auth: couldn't find user " << user << ", " << systemUsers << endl;
                    conn->done(); // return to pool
                    return false;
                }
            }

            pwd = userObj.getStringField("pwd");

            conn->done(); // return to pool
        }
        return true;
    }

    Status DBClientShardResolver::chooseWriteHost( const string& shardName,
                                                   ConnectionString* shardHost ) const {

        // Declare up here for parsing later
        string errMsg;

        // Special-case for config
        if (shardName == "config") {
            *shardHost = ConnectionString::parse( configServer.modelServer(), errMsg );
            dassert( errMsg == "" );
            return Status::OK();
        }

        //
        // First get the information about the shard from the shard cache
        //

        // Internally uses our shard cache, does no reload
        Shard shard = Shard::findIfExists( shardName );
        if ( shard.getName() == "" ) {
            return Status( ErrorCodes::ShardNotFound,
                           string("unknown shard name ") + shardName );
        }
        return findMaster(shard.getConnString().toString(), shardHost);
    }

    ShardManager::ShardManager( DBConfig * config , string ns , ShardKeyPattern pattern ) : _config( config ) , _ns( ns ) , _key( pattern ){
        Shard temp(0);
        
        ScopedDbConnection conn( temp.modelServer() );
        auto_ptr<DBClientCursor> cursor = conn->query( temp.getNS() , BSON( "ns" <<  ns ) );
        while ( cursor->more() ){
            Shard * s = new Shard( this );
            BSONObj d = cursor->next();
            s->unserialize( d );
            _shards.push_back( s );
            s->_id = d["_id"].wrap().getOwned();
        }
        conn.done();
        
        if ( _shards.size() == 0 ){
            Shard * s = new Shard( this );
            s->_ns = ns;
            s->_min = _key.globalMin();
            s->_max = _key.globalMax();
            s->_server = config->getPrimary();
            s->_markModified();
            
            _shards.push_back( s );
            
            log() << "no shards for:" << ns << " so creating first: " << s->toString() << endl;
        }

        _sequenceNumber = ++NextSequenceNumber;
    }

    bool Shard::moveIfShould( Shard * newShard ){
        Shard * toMove = 0;
       
        if ( newShard->countObjects() <= 1 ){
            toMove = newShard;
        }
        else if ( this->countObjects() <= 1 ){
            toMove = this;
        }
        else {
            log(1) << "don't know how to decide if i should move inner shard" << endl;
        }

        if ( ! toMove )
            return false;
        
        string newLocation = grid.pickServerForNewDB();
        if ( newLocation == getServer() ){
            // if this is the best server, then we shouldn't do anything!
            log(1) << "not moving shard: " << toString() << " b/c would move to same place  " << newLocation << " -> " << getServer() << endl;
            return 0;
        }

        log() << "moving shard (auto): " << toMove->toString() << " to: " << newLocation << " #objcets: " << toMove->countObjects() << endl;

        string errmsg;
        massert( (string)"moveAndCommit failed: " + errmsg , 
                 toMove->moveAndCommit( newLocation , errmsg ) );
        
        return true;
    }

    bool Balancer::_checkOIDs() {
        vector<Shard> all;
        Shard::getAllShards( all );

        map<int,Shard> oids;

        for ( vector<Shard>::iterator i=all.begin(); i!=all.end(); ++i ) {
            Shard s = *i;
            BSONObj f = s.runCommand( "admin" , "features" , true );
            if ( f["oidMachine"].isNumber() ) {
                int x = f["oidMachine"].numberInt();
                if ( oids.count(x) == 0 ) {
                    oids[x] = s;
                }
                else {
                    log() << "error: 2 machines have " << x << " as oid machine piece " << s.toString() << " and " << oids[x].toString() << endl;
                    s.runCommand( "admin" , BSON( "features" << 1 << "oidReset" << 1 ) , true );
                    oids[x].runCommand( "admin" , BSON( "features" << 1 << "oidReset" << 1 ) , true );
                    return false;
                }
            }
            else {
                log() << "warning: oidMachine not set on: " << s.toString() << endl;
            }
        }
        return true;
    }

        void _delete( Request& r , DbMessage& d, ShardManager* manager ){

            int flags = d.pullInt();
            bool justOne = flags & 1;
            
            uassert( "bad delete message" , d.moreJSObjs() );
            BSONObj pattern = d.nextJsObj();
            
            if ( manager->hasShardKey( pattern ) ){
                Shard& s = manager->findShard( pattern );
                doWrite( dbDelete , r , s.getServer() );
                return;
            }
            
            if ( ! justOne && ! pattern.hasField( "_id" ) )
                throw UserException( "can only delete with a non-shard key pattern if can delete as many as we find" );
            
            vector<Shard*> shards;
            manager->getShardsForQuery( shards , pattern );
            
            set<string> seen;
            for ( vector<Shard*>::iterator i=shards.begin(); i!=shards.end(); i++){
                Shard * s = *i;
                if ( seen.count( s->getServer() ) )
                    continue;
                seen.insert( s->getServer() );
                doWrite( dbDelete , r , s->getServer() );
            }
        }

    bool setShardVersion(DBClientBase& conn,
                         const string& ns,
                         const string& configServerPrimary,
                         ChunkVersion version,
                         ChunkManager* manager,
                         bool authoritative,
                         BSONObj& result) {

        BSONObjBuilder cmdBuilder;
        cmdBuilder.append("setShardVersion", ns);
        cmdBuilder.append("configdb", configServerPrimary);

        Shard s = Shard::make(conn.getServerAddress());
        cmdBuilder.append("shard", s.getName());
        cmdBuilder.append("shardHost", s.getConnString());

        if (ns.size() > 0) {
            version.addToBSON(cmdBuilder);
        }
        else {
            cmdBuilder.append("init", true);
        }

        if (authoritative) {
            cmdBuilder.appendBool("authoritative", 1);
        }

        BSONObj cmd = cmdBuilder.obj();

        LOG(1) << "    setShardVersion  " << s.getName() << " " << conn.getServerAddress()
               << "  " << ns << "  " << cmd
               << (manager ? string(str::stream() << " " << manager->getSequenceNumber()) : "");

        return conn.runCommand("admin", cmd, result, 0);
    }

 Shard& ShardManager::findShard( const BSONObj & obj ){
     
     for ( vector<Shard*>::iterator i=_shards.begin(); i != _shards.end(); i++ ){
         Shard * s = *i;
         if ( s->contains( obj ) )
             return *s;
     }
     throw UserException( "couldn't find a shard which should be impossible" );
 }

bool Shard::isIdentical(Shard *other)
{
    if (_type != other->_type) return false;
    if (count() != other->count()) return false;
    for (Shard *mine = _first, *yours = other->_first; mine;
        mine = mine->_next, yours = yours->_next)
        if (!mine->isIdentical(yours)) return false;
    return true;
}

    Shard* ShardManager::findShardOnServer( const string& server ) const {

        for ( vector<Shard*>::const_iterator i=_shards.begin(); i!=_shards.end(); i++ ){
            Shard* s = *i;
            if ( s->getServer() == server )
                return s;
        }

        return 0;
    }

Token *Command::arg(int idx)
{
    for(Shard *it = first(); it; it = it->next())
    {
        if(idx--) continue;
        it = it->first();
        if(!it || it->type() != BLOCK) break;
        return (Token*) it->first();
    }
    return 0;
}

 void ShardManager::ensureIndex(){
     set<string> seen;
     
     for ( vector<Shard*>::const_iterator i=_shards.begin(); i!=_shards.end(); i++ ){
         Shard* s = *i;
         if ( seen.count( s->getServer() ) )
             continue;
         seen.insert( s->getServer() );
         s->ensureIndex();
     }
 }

    // Deprecated, will move to the strategy itself
    Shard Request::primaryShard() const {
        assert( _didInit );

        if ( _chunkManager ) {
            if ( _chunkManager->numChunks() > 1 )
                throw UserException( 8060 , "can't call primaryShard on a sharded collection" );
            return _chunkManager->findChunk( _chunkManager->getShardKey().globalMin() )->getShard();
        }
        Shard s = _config->getShard( getns() );
        uassert( 10194 ,  "can't call primaryShard on a sharded collection!" , s.ok() );
        return s;
    }

 void remove( const string& name ) {
     scoped_lock lk( _mutex );
     for ( map<string,Shard>::iterator i = _lookup.begin(); i!=_lookup.end(); ) {
         Shard s = i->second;
         if ( s.getName() == name ) {
             _lookup.erase(i++);
         }
         else {
             ++i;
         }
     }
 }