[ECE-Tools] Multi-threaded SCD Doesn’t Work as Expected

[YPyltiai]

Internal ID: MAGECLOUD-3611

Background:

• https://magentocommeng.slack.com/archives/C8CBB6K9V/p1557737159442700
• MAGECLOUD-3382: Increase default SCD_THREADS to 3 #457 added multi-thread SCD back since it was removed in earlier versions during refactoring
• Users now observe issues with SCD, which are common across multiple projects

To Do:

• Investigate if it’s the issue in code or some library is outdated (per @hostep comment)
• Check if thread override for compact strategy still works as expected (in Slack users mentioned that it looks broken too)
• Review PR mentioned in Slack, which is possibly able to help resolving the issue

[hostep]

Since the free Slack version doesn't keep messages around for a long time, here's some links which might stand the test of time a bit better :)

• first bullet point refers to some observations I made on my local machine (this doesn't mean per sé that it will happen on the cloud): Implement Better Error Handling and Fix Waits on Null PIDs in Parallel SCD Execution magento2#22607 (comment) & Implement Better Error Handling and Fix Waits on Null PIDs in Parallel SCD Execution magento2#22607 (comment)
• the third bullet point refers to the same PR: Implement Better Error Handling and Fix Waits on Null PIDs in Parallel SCD Execution magento2#22607

Additionally, @ihor-sviziev is on a mission to find more issues with (multi-threaded) SCD execution which might be interesting to follow, for example:

• Static content deploy - Randomly css files not generated magento2#22880
• Static content deploy - Don't shows error message, just stack trace magento2#22882
• Static content deploy - Parallel execution - Not fails in case of exception magento2#22883

[ihor-sviziev]

I think better idea to fix these issues not inside ece tools, but inside magento itself and maybe apply these patches inside ece tools for versions that don’t have these fixes

For two issues I already created PRs:
magento/magento2#22884
magento/magento2#22886

[oshmyheliuk]

@ihor-sviziev Thank you.
We'll add patches to ece-tools after merging your fixes into the core.

[shiftedreality]

Here is a good example of failing on Travis CI builds https://travis-ci.com/magento/ece-tools/jobs/199529919

[YPyltiai]

@hostep , is magento/magento2#22563 also related?

[ihor-sviziev]

@hostep , is magento/magento2#22563 also related?

Yes, but it’s getting fixed by magento/magento2#22607

[hostep]

is magento/magento2#22563 also related?

Indeed, but it's only broken on the 2.3-develop branch, the change didn't happen yet in a stable version.

So if we're lucky, it won't be broken in 2.3.2. As long as magento/magento2@7421dfb isn't being included before magento/magento2#22607 gets included as well. So maybe someone should talk to the people involved with releasing new versions to make sure this doesn't happen :)

[YPyltiai]

Should be fixed by #527

[YPyltiai]

Resolved in #530
Current tests are all passing as expected