Socketclustser with acknowledgment not working

Question

I try to use socketCluster with acknowledgment in NodeJS.

I follow the code in this page: https://socketcluster.io/docs/basic-usage/

[Server] Publish to a channel and wait for acknowledgement

(async () => {
  try {
    // Publish data; wait for an acknowledgement from the back end broker (if it exists).
    await agServer.exchange.invokePublish('foo', 'This is some more data');
  } catch (error) {
    // ... Handle potential error if broker does not acknowledge before timeout.
  }
})();

But I don't get an acknowledgment and I don't know what is missing. I have tried uploading the socket cluster server with this option {ackTimeout: 10000}, but it didn't help. How do I know if the message was received?

Answer 1

To reply to your last comment @Lior. The "catch" block will be executed if the ACK has not been received. How to properly retry = I don't know. I am not a SocketCluster expert, but it seems there is no automatic mechanism to handle this. You could put a "do / while" loop around the try / catch block (by preventing infinite loop) :

let i = 0;
let callIsSuccessful = false;
do {
  try {
    // Publish data; wait for an acknowledgement from the back end broker (if it     exists).
    await agServer.exchange.invokePublish('foo', 'This is some more data');
    callIsSuccessful = true;
  } catch (error) {
        // ... Handle potential error if broker does not acknowledge before timeout.
  }
} while (i++ < MAX_RETRIES && (!callIsSuccessful))

You could also recall the function which make the publish action, by recursive way :

callingFunction(paramData, currentRetryNumber){
    if(currentRetryNumber >= MAX_RETRIES){
        return;
    }
    try {
        // Publish data; wait for an acknowledgement from the back end broker (if it     exists).
        await agServer.exchange.invokePublish('foo', 'This is some more data');
    } catch (error) {
        callingFunction(paramData, ++currentRetryNumber);
        // ... Handle potential error if broker does not acknowledge before timeout.
    }
}
(async () => {
    callingFunction(paramData, 0);
})();

Is it satisfying ? ;)