MongoDB ConnectionException SocketException

[DennisKragekjaer]

Hi, in my Flutter project I keep getting this:

MongoDB ConnectionException: connection closed: SocketException: Connection reset by peer (OS Error: Connection reset by peer, errno = 54)

Almost like every 5 min. Then when trying to call again, it works.
Its happening on iOS, both in simulator and on device. Does anyone know why that is popping up.

[giorgiofran]

No idea. To which kind of server are you connecting to? Did you get a look on the internet about similar problems in flutter?

[DennisKragekjaer]

Hi again.

I’m using mondodb Atlas.
Yea I searched the net for similar issues, but I didn’t find a solution to the problem.

I had to code some retry mechanism but it seems a bit weird to me that I need to do that.
I tried setting a timeout to calls.

[giorgiofran]

Give a look to issue #328 .

[TimeLord2010]

I also noticed this. I created a script that migrated data from mysql to mongodb, Mysql was on the same machine, but mongo was on atlas and it is a serverless instance.

I would say that every 5 to 10 min I got this error and I needed to restart the script. I had to handle it by creating a function:

Future<T> persistentMongoOperation<T>(Future<T> Function() func) async {
  for (var i = 0; i < 2; i++) {
    try {
      var r = await func();
      return r;
    } on ConnectionException {
      logger.error('Connection exception: Retrying...');
      await Future.delayed(Duration(seconds: 2));
      await closeMongoConnection();
    }
  }
  throw Exception('Failed to process operation');
}

Where func is a method that is smart enough to cache the mongo connection and open the connection if not already.

Anyway, the thing is, the nodejs driver for mongodb has a retry option under retryWrites and retryReads fields.

Its not clear if these options are able to be passed in the connection string. That, I did not test. But if not, that would be a great thing to add in the dart package here.