promise.timeout() and 'eventually' returned response

[jefflage]

we're trying to track down an issue in prod where one of the async operations (an HTTP call using request) starts timing out on every call. we're struggling to track down what triggers it, and it occurred to me that i don't know if the call is never returning, or simple not returning within the time we pass to .timeout(). what happens when call eventually returns / promise resolves?

we have the calls inlined like this:

return fm_proxy.for_client(document.data._client).request(fmurl, false, config.event_download_config)
    .timeout(config.event_load_timeout)

can i just assign the promise returned from the first time to a variable and call then() on that to track when it eventually returns?

[briancavalier]

Hey @jefflage. Yeah, you could add a .then(logInfo, logError) to the promise returned from .request to see what the outcome is.

Does that help?

[rkaw92]

You should be able to use the following chaining pattern, since .timeout() simply returns a new promise:

var longRunningOperationPromise = fm_proxy.for_client(document.data._client).request(fmurl, false, config.event_download_config);
return longRunningOperationPromise.then(function callSucceeded(value){
  console.info('Call eventually succeeded:', value);
  return value;
}, function callFailed(reason){
  console.error('Call failed:', reason);
  return when.reject(reason); // or throw reason - works just as well; just remember that not producing an error will hide the failure by preventing error propagation!
}).timeout(config.event_load_timeout);

[briancavalier]

@rkaw92 Thanks for the nice example :)

[jefflage]

duh. i was trying to over complicate it. thanks @rkaw92 and @briancavalier

[briancavalier]

@jefflage No prob, as always.