mongodb/dbgrid/request.cpp

/* dbgrid/request.cpp

   Top level handling of requests (operations such as query, insert, ...)
*/

/**
*    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/>.
*/

/* TODO
   _ GridD


   _ concurrency control.
     _ connection pool
     _ hostbyname_nonreentrant() problem
   _ gridconfig object which gets config from the grid db.
     connect to iad-sb-grid
   _ limit() works right?
   _ KillCursors

   later
   _ secondary indexes
*/

#include "stdafx.h"
#include "../grid/message.h"
#include "../db/dbmessage.h"
#include "../client/connpool.h"

const char *tempHost = "localhost:27018";

void getMore(Message& m, MessagingPort& p) {
  DbMessage d(m);
  const char *ns = d.getns();

  cout << "TEMP: getmore: " << ns << endl;

  ScopedDbConnection dbcon(tempHost);
  DBClientConnection &c = dbcon.conn();

  Message response;
  bool ok = c.port().call(m, response);
  uassert("dbgrid: getmore: error calling db", ok);
  p.reply(m, response, m.data->id);

  dbcon.done();
}

bool runCommandAgainstRegistered(const char *ns, BSONObj& jsobj, BSONObjBuilder& anObjBuilder);

/* got query operation from a database */
void queryOp(Message& m, MessagingPort& p) {
  DbMessage d(m);
  QueryMessage q(d);
  bool lateAssert = false;
  try { 
      if( q.ntoreturn == -1 && strstr(q.ns, ".$cmd") ) {
          BSONObjBuilder builder;
          cout << q.query.toString() << endl;
          bool ok = runCommandAgainstRegistered(q.ns, q.query, builder);
          if( ok ) { 
              BSONObj x = builder.done();
              replyToQuery(p, m, x);
              return;
          }
      }

      ScopedDbConnection dbcon(tempHost);
      DBClientConnection &c = dbcon.conn();
      Message response;
      bool ok = c.port().call(m, response);
      uassert("dbgrid: error calling db", ok);
      lateAssert = true;
      p.reply(m, response, m.data->id);
      dbcon.done();
  }
  catch( AssertionException& e ) { 
      assert( !lateAssert );
      BSONObjBuilder err;
      err.append("$err", string("dbgrid ") + (e.msg.empty() ? "dbgrid assertion during query" : e.msg));
      BSONObj errObj = err.done();
      replyToQuery(p, m, errObj);
      return;
  }
}

void writeOp(int op, Message& m, MessagingPort& p) {
  DbMessage d(m);
  const char *ns = d.getns();

  ScopedDbConnection dbcon(tempHost);
  DBClientConnection &c = dbcon.conn();

  c.port().say(m);

  dbcon.done();
/*
  while( d.moreJSObjs() ) {
    BSONObj js = d.nextJsObj();
    const char *ns = d.getns();
    assert(*ns);
  }
*/
}

void processRequest(Message& m, MessagingPort& p) {
    int op = m.data->operation();
    assert( op > dbMsg );
    if( op == dbQuery ) { 
        queryOp(m,p);
    }
    else if( op == dbGetMore ) { 
        getMore(m,p);
    }
    else {
        writeOp(op, m, p);
    }
}