refactor: simplify Ubuntu MATE build workflow and improve environment variable handling

.github/workflows/ubuntu-mate-build.yml

@@ -1,10 +1,5 @@
 name: Ubuntu MATE build
 
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
 on:
   schedule:
     - cron: '0 3 * * *'
@@ -17,18 +12,10 @@ on:
     tags: [ 'v*.*.*' ]
   pull_request:
     branches: [ "main" ]
-
-env:
-  # Use docker.io for Docker Hub if empty
-  REGISTRY: ghcr.io
-  # github.repository as <account>/<repo>
-  IMAGE_NAME: ${{ github.repository }}/containerdesk-ubuntu-mate
-
+  workflow_dispatch:
 
 jobs:
-
   build_mate:
-
     runs-on: ubuntu-latest
     permissions:
       contents: read
@@ -38,43 +25,82 @@ jobs:
       id-token: write
 
     steps:
+      - name: Set registry and token
+        run: |
+          if [[ "${{ github.server_url }}" == "https://github.com" ]]; then
+            echo "REGISTRY=ghcr.io" >> $GITHUB_ENV
+            echo "CONTAINER_TOKEN=${{ secrets.GITHUB_TOKEN }}" >> $GITHUB_ENV
+          else
+            # Forgejo/Gitea uses the instance domain as registry
+            echo "REGISTRY=$(echo ${{ github.server_url }} | sed 's|https://||')" >> $GITHUB_ENV
+            echo "CONTAINER_TOKEN=${{ secrets.FORGEJOTOKEN }}" >> $GITHUB_ENV
+          fi
+
+      - name: Set image name
+        run: |
+          echo "IMAGE_NAME=$(echo ${{ github.repository }}/containerdesk-ubuntu-mate | tr '[:upper:]' '[:lower:]')" >> $GITHUB_ENV
+
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
-      # Workaround: https://github.com/docker/build-push-action/issues/461
-      - name: Setup Docker buildx
-        uses: docker/setup-buildx-action@79abd3f86f79a9d68a23c75a09a9a85889262adf
-
-      # Login against a Docker registry except on PR
-      # https://github.com/docker/login-action
-      - name: Log into registry ${{ env.REGISTRY }}
+      - name: Log in to the Container registry
         if: github.event_name != 'pull_request'
-        uses: docker/login-action@28218f9b04b4f3f62068d7b6ce6ca5b26e35336c
+        uses: docker/login-action@v3
         with:
           registry: ${{ env.REGISTRY }}
           username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          password: ${{ env.CONTAINER_TOKEN }}
 
-      # Extract metadata (tags, labels) for Docker
-      # https://github.com/docker/metadata-action
-      - name: Extract Docker metadata
-        id: meta
-        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
-        with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+      - name: Extract branch name
+        shell: bash
+        run: |
+          BRANCH_NAME="${GITHUB_HEAD_REF:-${GITHUB_REF#refs/heads/}}"
+          BRANCH_NAME_CLEAN=$(echo "$BRANCH_NAME" | sed 's/[^a-zA-Z0-9._-]/-/g')
+          echo "BRANCH_NAME=$BRANCH_NAME" >> $GITHUB_ENV
+          echo "BRANCH_NAME_CLEAN=$BRANCH_NAME_CLEAN" >> $GITHUB_ENV
+
+      - name: Generate build version
+        id: version
+        run: |
+          BUILD_DATE=$(date +'%Y%m%d')
+          SHORT_SHA=$(git rev-parse --short HEAD)
+          echo "BUILD_VERSION=$BUILD_DATE-$SHORT_SHA" >> $GITHUB_ENV
+          echo "BUILD_DATE=$BUILD_DATE" >> $GITHUB_ENV
+          echo "SHORT_SHA=$SHORT_SHA" >> $GITHUB_ENV
+
+      - name: Generate Docker tags for main branch
+        if: env.BRANCH_NAME == 'main'
+        run: |
+          echo "DOCKER_TAGS<<EOF" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ env.BUILD_VERSION }}" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ env.BUILD_DATE }}" >> $GITHUB_ENV
+          echo "EOF" >> $GITHUB_ENV
+
+      - name: Generate Docker tags for development branches
+        if: env.BRANCH_NAME != 'main'
+        run: |
+          echo "DOCKER_TAGS<<EOF" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:dev-${{ env.BRANCH_NAME_CLEAN }}-${{ env.BUILD_VERSION }}" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:dev-${{ env.BRANCH_NAME_CLEAN }}-latest" >> $GITHUB_ENV
+          echo "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:dev-latest" >> $GITHUB_ENV
+          echo "EOF" >> $GITHUB_ENV
+
+      # Workaround: https://github.com/docker/build-push-action/issues/461
+      - name: Setup Docker buildx
+        uses: docker/setup-buildx-action@v3
 
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action
       - name: Build and push Docker image
         id: build-and-push
-        uses: docker/build-push-action@ac9327eae2b366085ac7f6a2d02df8aa8ead720a
+        uses: docker/build-push-action@v6
         with:
           context: ./ubuntu-mate
           file: ./ubuntu-mate/Dockerfile
           platforms: linux/amd64
           push: ${{ github.event_name != 'pull_request' }}
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
+          tags: ${{ env.DOCKER_TAGS }}
           cache-from: type=gha
           cache-to: type=gha,mode=max