MongoDB: Error setting TTL index on collection : sessions

Question

Initially this error message started appearing very infrequently, but started to appear more regularly and now appears 4/5 times I run my application.

I\'m handling

Answer 1

As I said in your comment, essentially Express is receiving connections before the session store is fully connected. The solution is to wait for the connection to occur before allowing your application to start listening.

You can avoid this problem by using a callback on MongoStore creation, or passing in an already active connection.

Example using connect-mongo's Callback

var sessionStore = new MongoStore({ url: 'someConnectionUrl', db: 'audio-drop' }, function(e) {

  var cookieParser = express.cookieParser('waytoblue');
  app.use(cookieParser);

  app.use(express.session({
    store: sessionStore
  }));

  app.listen();
});

Simple Mongoose Example

var mongoose = require('mongoose');

mongoose.connect('localhost', function(e) {
  // If error connecting
  if(e) throw e;

  var sessionStore = new MongoStore({ mongoose_connection: mongoose.connection }),
      cookieParser = express.cookieParser('waytoblue');

  app.use(cookieParser);

  app.use(express.session({
    store: sessionStore
  }));

  app.listen();
});