Fix for unsubscription new subscription race condition

[elorzafe]

Issue #, if available:
Fixes #4852
Description of changes:
Fix race condition during unsubscribe and subscribe

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[manueliglesias]

LGTM 👍

[codecov]

Codecov Report

Merging #4956 into master will decrease coverage by <.01%.
The diff coverage is 14.28%.

@@            Coverage Diff             @@
##           master    #4956      +/-   ##
==========================================
- Coverage   76.39%   76.38%   -0.01%     
==========================================
  Files         175      175              
  Lines        9667     9668       +1     
  Branches     1982     1982              
==========================================
  Hits         7385     7385              
- Misses       2135     2136       +1     
  Partials      147      147

Impacted Files	Coverage Δ
...pubsub/src/Providers/AWSAppSyncRealTimeProvider.ts	18.61% <14.28%> (-0.06%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3744cc9...516e64e. Read the comment docs.

[houmark]

Release today @elorzafe @manueliglesias? — can't wait to see if this stabilizes our random non-working subscriptions — this may be related to #4733.

[elorzafe]

@houmark

Release today @elorzafe @manueliglesias? — can't wait to see if this stabilizes our random non-working subscriptions — this may be related to #4733.

Is already published on @unstable tag on npm

[houmark]

Is already published on @unstable tag on npm

OK, trying that one out :)

[houmark]

@elorzafe I mentioned before that some errors in subscriptions are not catchable with the error callback. I've had the pleasure of being on a super unstable internet connection the last few days with huge packet loss and a good percentage of subscription connections error out, but my error function does not get the callback.

The console shows the following error when this handskake error happens and it would be nice to be able to react to that in the error callback, with the intent to retry connecting:

AWSAppSyncRealTimeProvider.ts:620 WebSocket connection to 'wss://retracted.appsync-realtime-api.us-east-1.amazonaws.com/graphql?header=....retracted.....=&payload=e30=' failed: WebSocket opening handshake timed out
(anonymous) @ AWSAppSyncRealTimeProvider.ts:620
(anonymous) @ AWSAppSyncRealTimeProvider.ts:619
(anonymous) @ AWSAppSyncRealTimeProvider.ts:632
step @ AWSAppSyncProvider.ts:204
(anonymous) @ AWSAppSyncProvider.ts:204
(anonymous) @ AWSAppSyncProvider.ts:204
push../node_modules/@aws-amplify/pubsub/lib-esm/Providers/AWSAppSyncRealTimeProvider.js.__awaiter @ AWSAppSyncProvider.ts:204
AWSAppSyncRealTimeProvider._initializeHandshake @ AWSAppSyncRealTimeProvider.ts:613
(anonymous) @ Retry.ts:37
step @ Reachability.ts:25
(anonymous) @ Reachability.ts:25
(anonymous) @ Reachability.ts:25
push../node_modules/@aws-amplify/core/lib-esm/Util/Retry.js.__awaiter @ Reachability.ts:25
retry @ Retry.ts:26
jitteredExponentialRetry @ Retry.ts:78
(anonymous) @ AWSAppSyncRealTimeProvider.ts:606
step @ AWSAppSyncProvider.ts:204
(anonymous) @ AWSAppSyncProvider.ts:204
(anonymous) @ AWSAppSyncProvider.ts:204
push../node_modules/@aws-amplify/pubsub/lib-esm/Providers/AWSAppSyncRealTimeProvider.js.__awaiter @ AWSAppSyncProvider.ts:204
AWSAppSyncRealTimeProvider._initializeRetryableHandshake @ AWSAppSyncRealTimeProvider.ts:604
(anonymous) @ AWSAppSyncRealTimeProvider.ts:580
step @ AWSAppSyncProvider.ts:204
(anonymous) @ AWSAppSyncProvider.ts:204
fulfilled @ AWSAppSyncProvider.ts:204

I know this has been merged, and if you like, I can create a new issue with the information above.

And on a stable connection, things seem much more stable, so if it's possible to catch and handle similar issues like the above, I think it's possible for a developer to retry/handle any type of error in a sensible way.

[github-actions]

This pull request has been automatically locked since there hasn't been any recent activity after it was closed. Please open a new issue for related bugs.

Looking for a help forum? We recommend joining the Amplify Community Discord server *-help channels or Discussions for those types of questions.