fix(core): Ensure job processor does not reprocess amended executions #11438
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
n8n-assistant
bot
added
core
despairblue
reviewed
Oct 28, 2024
| * cause a crashed execution to be enqueued. We refrain from processing it, | ||
| * until we have reworked both mechanisms to prevent this scenario. | ||
| */ | ||
| if (execution.status === 'crashed') return { success: false }; |
There was a problem hiding this comment.
Are we using the return value for anything?
I only found this function being called here, and there we're not using the result:
There was a problem hiding this comment.
Historically we never used the result, we've only relied on promise resolution or rejection. The important bit is the early return to resolve the promise without any reprocessing of the crashed execution. I went for { success: false } to keep the return type simple, aligned with what is already there.
despairblue
approved these changes
Oct 28, 2024
n8n
|
||||||||||||||||||||||||||||
| Project |
n8n
|
| Branch Review |
pay-2100-cannot-read-properties-of-undefined-reading-node
|
| Run status |
|
| Run duration | 04m 36s |
| Commit |
|
| Committer | Iván Ovejero |
| View all properties for this run ↗︎ | |
| Test results | |
|---|---|
Failures
|
0
|
Flaky
|
0
|
Pending
|
0
|
Skipped
|
0
|
Passing
|
460
|
| View all changes introduced in this branch ↗︎ | |
|
✅ All Cypress E2E specs passed |
ivov
deleted the
pay-2100-cannot-read-properties-of-undefined-reading-node
branch
Merged
|
Got released with |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
This PR fixes an edge case caused by an unwanted interaction between Bull's implicit retry mechanism and n8n's execution recovery mechanism.
When a worker crashes mid-execution, it fails to send a heartbeat back to Redis, prompting Bull to re-enqueue the job. When the worker restarts, its event bus looks at the filesystem logs and marks the execution as
crashedand amends its data. But, the job is still in the queue. When this worker (or another worker, makes no difference) receives the job, the processor tries to run the execution but finds its amended data is lacking some of the data needed for execution, henceCannot read properties of undefined (reading 'node')whereundefinedshould have been the zeroth item in thenodeExecutionStack.This unwanted interaction comes from two legacy systems that we are planning to rework in future, so this PR ensures that amended executions cannot be reprocessed by workers.
Related Linear tickets, Github issues, and Community forum posts
Review / Merge checklist
release/backport(if the PR is an urgent fix that needs to be backported)