"Error POSTing DOM" happening regularly

[krasnoukhov]

Thanks to the merge of #234 we've been able to upgrade to the most recent Percy stack. However, I've noticed that our builds fail to create all snapshots with the log message originating here:

https://github.com/percy/ember-percy/blob/40cb769830e5688238c34ffa7b9f03b2d9e53d15/addon-test-support/%40percy/ember/index.js#L137

The message is like this:

LOG: [percy] Error POSTing DOM, disabling: TypeError: Failed to fetch

This happened 3-4 times already on different builds since yesterday, including the baseline builds. This makes things really problematic since it results in "bad" baseline build, which in turn results in a lot of diffs for branch builds.

Here's a most recent example: https://percy.io/simplepractice/simplepractice/builds/7002777

Not sure where that error is coming from (percy agent?) but perhaps this addon can add a retry logic of sorts? Any update would be appreciated.

[krasnoukhov]

Any update on this? Still happening regularly.

[wwilsman]

Hey @krasnoukhov!

Are there any other logs in the browser console when you see that error? According to search results, that error comes from fetch when there is something up with the response and it seems like it is typically cors related. The local percy server uses a cors middleware to accept all requests, so I wonder what may be happening in your case.

[krasnoukhov]

Thanks for the reply. Seems like this happens when agent is not running due to this message:

Warning: Skipping visual tests. PERCY_TOKEN was not provided

We have some conditions around PERCY_TOKEN which flake sometimes so that's the culprit. Sorry for the trouble