Fixing GitHub App OAuth Bad Credentials In Backstage

by Rajiv Sharma 55 views

Hey everyone, we're diving deep into a tricky issue some of you might be encountering with GitHub App OAuth in Backstage. Specifically, we're seeing those dreaded "Bad credentials" errors popping up, and it's time to get to the bottom of it.

Understanding the Issue: GitHub App OAuth and Bad Credentials

So, you've got your GitHub App all set up for your Backstage service, following the official docs to a T. You're using it for OAuth and seamless GitHub integration, probably on public github.com. Then, BAM! You hit a snag. When using a software template with the GitHub repo picker UI field, or even the catalog importer tool, you're seeing "HttpError: Bad credentials" when trying to create a pull request or analyze a repository. It's like your credentials suddenly went on vacation without telling you. This issue is particularly frustrating because it's intermittent, making it a real head-scratcher to debug.

The core of the problem seems to lie in how Backstage is refreshing the OAuth tokens for your GitHub App. When the refresh mechanism hiccups, the credentials become invalid, leading to the infamous "Bad credentials" error. This often manifests when interacting with GitHub through Backstage features like the scaffolder's repo picker or the catalog importer. These tools rely on the OAuth token to authenticate on behalf of the user, and when the token goes stale, things break down.

Now, the weird part is that this doesn't seem to affect everything equally. For instance, widgets on your GitHub homepage that use githubAuthApi and the signIn method seem to be immune. The difference? The scaffolder repo picker uses the getCredentials method of the scmAuthApi, which might be where the issue is lurking. One potential factor could be the enableExperimentalRedirectFlow configuration option, though it's unclear if this is a direct cause.

Why does this matter? Well, consistent authentication is crucial for a smooth developer experience. Imagine trying to demo a cool new feature, only to have it crash because of a credential error. Not a great look, right? Plus, a broken catalog importer can really throw a wrench in your efforts to keep your software catalog up-to-date.

The Workaround (For Now)

Okay, so you've hit the error. Don't panic! There's a workaround that seems to do the trick, at least temporarily:

  1. Head over to the authentication providers in your Backstage settings page.
  2. Log out of the GitHub provider.
  3. Log back in to the GitHub provider.

This little dance seems to reset things and get you back on track. But let's be real, this is a band-aid solution. We need to find the root cause and fix it for good.

Diving Deeper: Configuration and Context

Let's talk config. Most setups are pretty standard, following the GitHub SaaS (github.com) documentation. You've got your GitHub App configured, likely using the enableExperimentalRedirectFlow option, which might be a clue. The fact that homepage widgets using githubAuthApi and signIn aren't affected, while the scaffolder repo picker (using scmAuthApi's getCredentials) is, points to a potential difference in how these methods handle token refresh.

Understanding this context is key to finding a permanent fix. We need to dig into how these different APIs manage authentication and identify where the refresh process is failing.

Expected Behavior: Smooth Sailing with OAuth

Ideally, you should never see a "Bad credentials" error when making GitHub requests using OAuth credentials from a GitHub App. It should just work, seamlessly and reliably. That's the dream, right? We expect that using OAuth with a GitHub App should provide a secure and consistent authentication experience, allowing developers to interact with GitHub resources without interruption.

Reproduction Steps: Recreating the Issue

Want to see if you can reproduce the issue? Here's a recipe:

  1. Create a GitHub App.
  2. Configure the GitHub App in your Backstage app config, following the official documentation.
  3. (Maybe) Set experimental auth redirect flow = true.
  4. Use a GitHub scaffolder action that relies on the OAuth token from the GitHub repo picker.
  5. Cross your fingers (or don't!) and see if the "bad credentials" error pops up.

Why try to reproduce it? Because consistently recreating the issue is the first step to fixing it. Once we can reliably trigger the error, we can start digging into the code and figure out what's going wrong.

Potential Root Causes and Troubleshooting

Okay, let's brainstorm some potential culprits and how we might tackle them.

1. Token Refresh Issues

The most likely suspect is the token refresh mechanism. Here's what we need to investigate:

  • Token Expiration: Are the tokens expiring sooner than expected? We need to check the token lifetimes and ensure they're being refreshed before they become invalid.
  • Refresh Logic: Is there a bug in the token refresh logic itself? Maybe the refresh request isn't being sent correctly, or the response isn't being handled properly.
  • Concurrency: Could there be a race condition where multiple requests are trying to refresh the token at the same time, leading to conflicts?

To troubleshoot this, we can add logging around the token refresh process. We need to see when tokens are being refreshed, when they're expiring, and if any errors are occurring during the refresh.

2. Permissions and Scopes

Another possibility is that the GitHub App's permissions aren't set up correctly. Maybe the app doesn't have the necessary scopes to perform the actions being requested. We should double-check the app's configuration and ensure it has all the required permissions.

  • OAuth Scopes: Verify that the GitHub App has the necessary OAuth scopes for the operations it's performing (e.g., repo, read:org).
  • Installation Permissions: Ensure the app is installed on the correct repositories or organizations with the appropriate permissions.

3. Configuration Mismatches

It's always worth double-checking the configuration. A small typo or incorrect setting can lead to big problems.

  • App Credentials: Verify that the GitHub App ID and client secret are correctly configured in Backstage.
  • Callback URLs: Ensure the callback URLs are properly set up in both the GitHub App and Backstage.
  • Experimental Features: If using enableExperimentalRedirectFlow, consider whether this might be contributing to the issue.

4. Network Issues

While less likely, network connectivity problems could also cause intermittent issues. We should check for any network errors or timeouts that might be interfering with the token refresh process.

  • Firewall Rules: Make sure there are no firewall rules blocking communication between Backstage and GitHub.
  • DNS Resolution: Verify that DNS resolution is working correctly.

Call to Action: Let's Fix This Together!

This is where you come in, guys! We need to collaborate to get this sorted. If you've experienced this issue, or have any insights or potential solutions, please chime in. The original reporter is willing to submit a PR, but could use some guidance. Your experiences and expertise can help us pinpoint the root cause and develop a robust fix. We encourage everyone to share their findings, configuration details, and any troubleshooting steps they've tried. Together, we can ensure a smooth and reliable GitHub App OAuth experience in Backstage.

Next Steps: Contributing and Getting Involved

  • Share Your Experience: If you've encountered this issue, please share your setup, configuration, and any troubleshooting steps you've taken.
  • Review the Code: If you're familiar with the Backstage codebase, take a look at the authentication logic and see if you can spot any potential issues.
  • Test Solutions: Once we have some potential fixes, we'll need people to test them and verify that they resolve the issue.
  • Submit a PR: If you're able to identify a fix, please submit a pull request with your changes.

Let's make Backstage even better!

Have you read the Code of Conduct?

Yes, the reporter has confirmed they've read the Code of Conduct.

Are you willing to submit PR?

Yes, the reporter is willing to submit a PR but would like some more guidance. Let's help them out!