CI: Automatically generate 'latest tag' from 'tag' name instead of ha…

…rdcoding it.

Otherwise every time we change between buster-legacy and bullseye
we have to touch the release.yml file to change the tag name for
'latest' (e.g. 'buster-latest', 'bullseye-latest').

.github/workflows/release.yml

@@ -10,24 +10,28 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Get the version
-        id: get_version
-        run: echo ::set-output name=VERSION::${GITHUB_REF/refs\/tags\//}
-        shell: bash
+      - name: Set release tag to env variables $TAG
+      #  id: get_version
+      #  run: echo ::set-output name=VERSION::${GITHUB_REF/refs\/tags\//}
+      #  shell: bash
+        run: echo "TAG=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+      - name: Set 'latest tag' (e.g. buster-legacy-2022-04-19 -> buster-latest) to env variable $TAG_LATEST
+        run: python -c "t='$TAG'.split('-')[0]; print(f'TAG_LATEST={t}-latest')" >> $GITHUB_ENV
+      - run: echo "Release tag is '$TAG' and latest tag is '${{ env.TAG_LATEST }}'"
       - name: Login to GitHub Container Registry
         uses: docker/login-action@v3
         with:
           registry: ghcr.io
           username: ${{ github.repository_owner }}
           password: ${{ secrets.CR_PAT }}
       - name: Build base image (expanded disk) with latest tag
-        run: docker build -t ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:buster-legacy-latest --build-arg FILE_SUFFIX=autologin-ssh-expanded .
-      - name: Tag the base image with the versioned tag
-        run: docker tag ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:buster-legacy-latest ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ steps.get_version.outputs.VERSION }}
+        run: docker build -t ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG_LATEST }} --build-arg FILE_SUFFIX=autologin-ssh-expanded .
+      - name: Also tag the base image with the versioned tag
+        run: docker tag ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG_LATEST }} ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG }}
       - name: Build Mu image
-        run: docker build -t ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ steps.get_version.outputs.VERSION }}-mu --build-arg FILE_SUFFIX=mu .
+        run: docker build -t ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG }}-mu --build-arg FILE_SUFFIX=mu .
       - name: Push images to ghcr.io
         run: |
-          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ steps.get_version.outputs.VERSION }}-mu
-          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ steps.get_version.outputs.VERSION }}
-          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:buster-legacy-latest
+          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG }}-mu
+          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG }}
+          docker push ghcr.io/${{ github.repository_owner }}/qemu-rpi-os-lite:${{ env.TAG_LATEST }}

README.md

@@ -34,7 +34,7 @@ the hard work goes to them. The main difference in this version is that the
 has been updated to enable auto-login, SSH, and expand their filesystem size.
 
 These changes make these images useful for things like running automated
-tests on CI, like within GitHub Actions.
+tests on CI, e.g. GitHub Actions.
 
 ## How to use these images
 
@@ -61,7 +61,7 @@ docker run -it -p 5022:5022 ghcr.io/carlosperate/qemu-rpi-os-lite:bullseye-lates
 ## Available Images
 
 There are two main releases right now `buster-legacy-latest` and
-'bullseye-latest':
+`bullseye-latest`:
 
 ```
 ghcr.io/carlosperate/qemu-rpi-os-lite:bullseye-latest
@@ -71,15 +71,15 @@ ghcr.io/carlosperate/qemu-rpi-os-lite:bullseye-latest
 ghcr.io/carlosperate/qemu-rpi-os-lite:buster-legacy-latest
 ```
 
-Each Pi OS release has it's own tag, including the OS release date in this
+Each Pi OS release has its own tag, including the OS release date in this
 format:
 
 ```
-ghcr.io/carlosperate/qemu-rpi-os-lite:buster-yyyy-mm-dd-mu
+ghcr.io/carlosperate/qemu-rpi-os-lite:buster-yyyy-mm-dd
 ```
 
 There also is an additional tag on each release with the postfix `mu` in the
-tag name, which is an specialised image created specifically to contain the
+tag name, which is an specialised image created specifically to include the
 [Mu Editor](https://github.com/mu-editor/mu) dependencies pre-installed,
 which is used for CI tests on that project: