Ability to add custom metadata to pull requests

[Wazbat]

Is there any way to add custom information to pull requests? I'm setting up a ✨ fancy ✨CI system using github actions in my gitops repository, however I was wondering if there was any way we could add custom metadata to a PR?

For example, some PRs may or may not be trying to modify a kubernetes template, specifying an image digest to use. If the PR is indeed modifying an image digest/tag, I want to run certain tests, using stuff like the image digest, etc.

Now that's easy enough when creating the pull requests, as I have access to information about the code changes, in my case, when I create them from another action.

However, based on my understanding, there is no way to save any of that information for later. I can only control the following things:

• PR title
• PR body
• Labels
• Reviewers, projects, milestones, and other metadata

I've seen some hacky solutions, like using html comments to hide invisible metadata in PR bodies, however that feels like a really really janky solution, and not ideal

Is there any way around this? I feel this would be a great new feature, and would enable developers to make some pretty nifty intergrations without requiring a separate database to store this information

[Wazbat]

Now that I think about it, maybe I could output my metadata to a json file, then use https://github.com/actions/cache to store it in the repository cache to then fetch it later when running pull request checks? It's a shame there's no built in way, but I suppose that'd work?' Are there any better ways?

[airtower-luna]

The cache is not a reliable way to transmit data, cached data may get dropped whenever (usually when new objects need the space). Artifacts are reliable but have a limited lifetime, so they'll do for temporary data you want to pass to tools that run soon after PR creation, but not for data persistently associated with the PR.

[Wazbat]

The cache is not a reliable way to transmit data, cached data may get dropped whenever (usually when new objects need the space).

To be fair, I would only need the data immediately after the PR is created, when github runs the first pull request checks to make sure the PR is mergeable. I see the cache is supposed to last 7 days, or 10gb

Though artifacts do sound like they'd work, but aren't those stored on the job run? How would I find that in the PR?

[airtower-luna]

Artifacts are associated with a workflow run, yes. You'd probably have to look for the right workflow run (and then its artifacts) using the API. Not something I've done myself, but I know people have done that kind of thing.

And, well, how would you find a cache object from the PR? 😅

[Wazbat]

And, well, how would you find a cache object from the PR? 😅

Good question! Haha

I suppose I could use the pull request branch name or pull request number to build a unique cache key immediately after the PR is created. Then in the PR action, I can use the pull request context to fetch that object from cache

[gka038]

May I know if you found any great option to store metadata related to a PR?

[dmitrym0]

I recall seeing an action a while back that added hidden <!-- --> html to the description of the PR so that it wasn't visible to humans but was to the action. It was a simply hash-like API. Does anyone know what I'm referring to?

[alexkappa]

I think you are referring to probot/metadata.

[ericabouaf]

Found this thread looking for a similar solution on issues.
We ended up using Frontmatter with a triple backtick separator.

[kennethleider]

I am about to do this using git notes, was just searching for an example, but alas found none.

HASH=$(printf <pr_number> | git hash-object --stdin)
git notes --ref pull_request add -m "This is my metadata" $HASH
git notes --ref pull_request show $HASH
git push origin 'refs/notes/*'

and then when I need to read it

git fetch origin "+refs/notes/pull_request:refs/notes/pull_request"
HASH=$(printf <pr_number> | git hash-object --stdin)
git notes --ref pull_request show $HASH

[aviallon]

TIL git notes exists.

[michielbdejong]

@r-aaron-graham

you can use the GitHub API to store and retrieve metadata associated with pull requests

How? I wasn't able to find anything about this in the GitHub API docs.

[Wazbat]

I'm pretty sure he just pasted the thread into chatGPT and asked it to answer the question, and in typical fashion it just hallucinated everything, which combined with a lack of proofreading and blind-copy paste, just ended up confusing everyone more