CODEWITHSUNDEEP
mongodb
Farrukh Sarmad
Farrukh Sarmad

Reputation: 325

How can I detect mongodb reconnect failed event

I am using nodejs mongo driver in my application. I set up below options in the connection:

{
  connectTimeoutMS: 30000,
  socketTimeoutMS: 30000,
  // retry to connect for 120 times
  reconnectTries: 120,
  // wait 1 second before retrying
  reconnectInterval: 1000
};

It will try to re-connect 120 times if the connection is broken and 1 second for each delay. I need to listen on the server status changes during re-connect. I added below event listeners:

db.on('close', this.onClose.bind(this));
db.on('error', this.onError.bind(this));
db.on('timeout', this.onTimeout.bind(this));
db.on('parseError', this.onParseError.bind(this));
db.on('reconnect', this.onReconnect.bind(this));

All the event listeners are working fine but my problem is how to detect that the reconnect failed after 120 times retries. For example, if the server is down then I will receive a close event. If the server is up during 120 seconds, I will receive reconnect event. But what if the server is not up in 120 seconds. How can I detect this change? Should I implement it by myself?

Upvotes: 1

Views: 1959

Answers (2)

kprist
kprist

Reputation: 210

There is a (somewhat) undocumented event type: reconnectFailed.

This is documented here: http://mongodb.github.io/node-mongodb-native/core/api/Server.html#event:reconnectFailed but only for the Server object. However it does seem to also be emitted by the Db object, like so:

db.on('reconnectFailed', (err) => {
  // do something here
});

I've verified this works also for the 2.2 version of the nodejs mongodb driver, just not documented there at all.

Upvotes: 2

IFebles
IFebles

Reputation: 338

You can do it like this:

// Do this on your global scope //
var connectionAttemps = 0;

var doThisInsideYourTriggeredErrorEvent = function () {
    connectionAttemps++;

    if (connectionAttemps >= 120)
    {
        // Here goes your logic to stop the reconnection attempts //
    }
    /* Here goes your implemented logic (if any) for the "onError" event */
}

Check if it helps.

PS: note that the content of my function goes inside the content of your OnError function.

Upvotes: 1

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