feat: add workflow to trigger image rebuilds across downstream repos

[waveywaves]

Summary

• Adds a new manually-dispatched GitHub Actions workflow trigger-image-rebuilds.yaml
• Triggers Konflux image rebuilds by updating .konflux/patches/.placeholder in each downstream repo
• Creates the .placeholder file if it doesn't already exist in a repo
• Uses the GitHub Contents API to commit directly (same pattern as tektoncd-results@e106311)

Inputs

Input	Required	Description
version	Yes	Release version (e.g., 1.15, 1.22, next) — maps to release-v{version}.x branch (next maps to main)
repo	No	Filter to a specific downstream repo name (empty = all repos)

How it works

1. Reads all downstream repo names from config/downstream/repos/*.yaml
2. For each repo, checks if the target branch exists
3. Checks if .konflux/patches/.placeholder exists on that branch
4. Creates or updates the file with rebuild <timestamp> content
5. The commit triggers Konflux to rebuild images

Test plan

• Dispatch workflow with version=1.15 and repo=tektoncd-results to test single-repo mode
• Verify the .placeholder file is updated and a Konflux build is triggered
• Dispatch with version=1.15 and empty repo to test all-repos mode

[pramodbindal]

for next version branch is next only

[divyansh42]

@waveywaves I think this will only work for the new config. i.e 1.21 and above
For the older config we need to have another workflow

[waveywaves]

@divyansh42 Thanks for the review! I looked into this and both old (1.15) and new (1.22) versions have .konflux/patches/*** in their CEL trigger filters:

# 1.15 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.15.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

# 1.22 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.22.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

So touching .konflux/patches/.placeholder should trigger builds on both old and new configs. Could you clarify what specifically about the old config (< 1.21) would not work with this approach? Is it something at the Konflux application/component level or a different repo structure?

Also fixed @pramodbindal's comment — next version now maps to the next branch instead of main.

[pramodbindal]

@divyansh42 Thanks for the review! I looked into this and both old (1.15) and new (1.22) versions have .konflux/patches/*** in their CEL trigger filters:

# 1.15 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.15.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

# 1.22 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.22.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

So touching .konflux/patches/.placeholder should trigger builds on both old and new configs. Could you clarify what specifically about the old config (< 1.21) would not work with this approach? Is it something at the Konflux application/component level or a different repo structure?

Also fixed @pramodbindal's comment — next version now maps to the next branch instead of main.

We are migrating all the releases to follow same pattern.

[divyansh42]

@divyansh42 Thanks for the review! I looked into this and both old (1.15) and new (1.22) versions have .konflux/patches/*** in their CEL trigger filters:

# 1.15 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.15.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

# 1.22 (tektoncd-pipeline controller push)
pipelinesascode.tekton.dev/on-cel-expression: event == "push" && target_branch
  == "release-v1.22.x" &&
  ("upstream/***".pathChanged() || ".konflux/patches/***".pathChanged() || ".konflux/rpms/***".pathChanged() || ...)

So touching .konflux/patches/.placeholder should trigger builds on both old and new configs. Could you clarify what specifically about the old config (< 1.21) would not work with this approach? Is it something at the Konflux application/component level or a different repo structure?
Also fixed @pramodbindal's comment — next version now maps to the next branch instead of main.

We are migrating all the releases to follow same pattern.

Thanks for clarifying that @pramodbindal
Yes, what I meant is config structure, earlier we were using different config structure for 1.20 and below release but now it is same for all the version.
I added the comment as I wasn't aware about the change.
Thanks @waveywaves