Allow manually publishing a release image in docker workflow (#7392)

Add a workflow_dispatch trigger that builds an existing release tag with the current workflow and publishes it to GHCR under that tag name (optionally also as latest). This allows republishing a release whose image failed to publish, since re-running the original run reuses the workflow file from the release tag.

Dispatched runs check out the given tag, publish like stable releases, and use their own concurrency group so pushes to master can't cancel them.

Co-authored-by: Michael Hogg <3495076+jedinerd@users.noreply.github.com>

.github/workflows/docker-release.yml

@@ -20,11 +20,22 @@ on:
   release:
     types:
       - released    # publishing of stable releases
+  workflow_dispatch:    # (re)publish the image for an existing stable release
+    inputs:
+      tag:
+        description: 'Existing release tag to build and publish (e.g. 2026-10-03-Release-3.1.0)'
+        required: true
+        type: string
+      latest:
+        description: 'Also update the "latest" tag'
+        required: true
+        type: boolean
+        default: true
 
-# Cancel earlier, unfinished runs of this workflow on the same branch (unless on release)
+# Cancel earlier, unfinished runs of this workflow on the same branch (unless publishing)
 concurrency:
-  group: "${{ github.workflow }} @ ${{ github.ref_name }}"
+  group: "${{ github.workflow }} @ ${{ inputs.tag || github.ref_name }}"
-  cancel-in-progress: ${{ github.event_name != 'release' }}
+  cancel-in-progress: ${{ github.event_name != 'release' && github.event_name != 'workflow_dispatch' }}
 
 env:
   GHCR_IMAGE: ghcr.io/cockatrice/servatrice
@@ -57,12 +68,14 @@ jobs:
     steps:
       - name: "Checkout"
         uses: actions/checkout@v7
+        with:
+          ref: ${{ case(github.event_name == 'workflow_dispatch', format('refs/tags/{0}', inputs.tag), '') }}
 
       - name: "Set up Docker buildx"
         uses: docker/setup-buildx-action@v4
 
       - name: "Login to GitHub Container Registry (GHCR)"
-        if: github.event_name == 'release' && github.event.release.prerelease == false
+        if: (github.event_name == 'release' && github.event.release.prerelease == false) || github.event_name == 'workflow_dispatch'
         id: login
         uses: docker/login-action@v4
         with:
@@ -70,7 +83,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ github.token }}
 
-      # Don't push for non-release triggers
+      # Don't push for non-publishing triggers
       - name: "Build image"
         if: steps.login.outcome != 'success'
         uses: docker/build-push-action@v7
@@ -120,7 +133,7 @@ jobs:
   # Create an OCI image index from the platform-specific image manifests
   index:
     name: "Publish multi-platform Servatrice image"
-    if: github.repository_owner == 'Cockatrice' && github.event_name == 'release' && github.event.release.prerelease == false
+    if: github.repository_owner == 'Cockatrice' && ((github.event_name == 'release' && github.event.release.prerelease == false) || github.event_name == 'workflow_dispatch')
     needs: build
     runs-on: ubuntu-slim    # https://github.com/actions/runner-images/blob/main/images/ubuntu-slim/ubuntu-slim-Readme.md
 
@@ -149,6 +162,8 @@ jobs:
           # if semver, also: type=semver,pattern={{version}} / {{major}}.{{minor}}
           tags: |
             type=ref,event=tag
+            type=raw,value=${{ inputs.tag }},enable=${{ github.event_name == 'workflow_dispatch' }}
+            type=raw,value=latest,enable=${{ github.event_name == 'workflow_dispatch' && inputs.latest }}
 
       # Add OCI annotations to image index and publish tags
       - name: "Create image index"
@@ -176,7 +191,7 @@ jobs:
 
       - name: "Inspect images"
         env:
-          GITHUB_TAG: ${{ github.ref_name }}
+          GITHUB_TAG: ${{ inputs.tag || github.ref_name }}
         run: |
           docker buildx imagetools inspect "$GHCR_IMAGE:latest"
           docker buildx imagetools inspect "$GHCR_IMAGE:$GITHUB_TAG"