Modifying targetRevision automatically

[djfinnoy]

Consider a simple mono-repo for application manifests:

├── apps
│   ├── team-a
│   │   ├── app-1a
│   │   ├── app-2a
│   │   └── app-3a
│   └── team-b
│       ├── app-1b
│       ├── app-2b
│       └── app-3b
│
└── app-of-apps
    ├── dev
    │   ├── team-a.yaml
    │   └── team-b.yaml
    └── prod
        ├── team-a.yaml
        └── team-b.yaml

apps/ contains the configuration for bespoke apps, their source code is kept in separate repositories.
app-of-apps/ contains the Application manifests for the apps in apps/.

Now let's assume that a developer makes a pull request against apps/team-a/app1-a while working on the source code for app1-a.
It would be nice if the targetRevision of app1-a in dev automatically jumped to the pull request branch, and returned to it's default (eg. main) after the pull request is closed.

I can think of a couple of ways to do this, but they all have drawbacks / don't feel very elegant:

• Tag tracking
• Git writeback to app-of-apps/dev/.argocd-source-<appname>.yaml via CI
• ArgoCD Application patching via CI

How would you do it?

[kostis-codefresh]

The Pull Request generator exists precisely for this scenario https://argo-cd.readthedocs.io/en/latest/operator-manual/applicationset/Generators-Pull-Request/ Have you seen it?

Full example here https://github.com/kostis-codefresh/preview-env-manifests/blob/main/argocd/smart-pr-generator.yml