Enable CI for custom Docker workspace image on Gitpod

Signed-off-by: Andrei Jiroh Halili <ajhalili2006@gmail.com>

.github/workflows/docker.yml

@@ -0,0 +1,102 @@
+name: Docker
+
+# 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: '30 22 * * *'
+  push:
+    branches: [ "main" ]
+    # Publish semver tags as releases.
+    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 }}
+
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      # This is used to complete the identity challenge
+      # with sigstore/fulcio when running outside of PRs.
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      # Install the cosign tool except on PR
+      # https://github.com/sigstore/cosign-installer
+      - name: Install cosign
+        if: github.event_name != 'pull_request'
+        uses: sigstore/cosign-installer@f3c664df7af409cb4873aa5068053ba9d61a57b6 #v2.6.0
+        with:
+          cosign-release: 'v1.13.1'
+
+
+      # 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 }}
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@28218f9b04b4f3f62068d7b6ce6ca5b26e35336c
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_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 }}
+
+      - uses: actions/checkout@v3
+      - uses: hadolint/hadolint-action@v3.1.0
+        with:
+          dockerfile: .gitpod.Dockerifle
+
+      # 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
+        with:
+          context: .
+          file: .gitpod.Dockerfile
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+
+      # Sign the resulting Docker image digest except on PRs.
+      # This will only write to the public Rekor transparency log when the Docker
+      # repository is public to avoid leaking data.  If you would like to publish
+      # transparency data even for private images, pass --force to cosign below.
+      # https://github.com/sigstore/cosign
+      - name: Sign the published Docker image
+        if: ${{ github.event_name != 'pull_request' }}
+        env:
+          COSIGN_EXPERIMENTAL: "true"
+        # This step uses the identity token to provision an ephemeral certificate
+        # against the sigstore community Fulcio instance.
+        run: echo "${{ steps.meta.outputs.tags }}" | xargs -I {} cosign sign {}@${{ steps.build-and-push.outputs.digest }}

.gitpod.Dockerfile

@@ -1,5 +1,13 @@
 # syntax=docker/dockerfile:1
-FROM gitpod/workspace-full
+FROM gitpod/workspace-full:latest as workspace
+
+WORKDIR /tmp
+RUN mkdir /home/gitpod/.local -pv \
+    && git clone https://git.sr.ht/~sircmpwn/scdoc && cd scdoc \
+    && make && sudo cp scdoc /usr/local/bin/scdoc && cd .. \
+    && git clone https://git.sr.ht/~emersion/hut && cd hut \
+    && make PREFIX=/home/gitpod/.local && sudo cp ./hut /usr/local/bin/hut \
+    && rm -rfv /tmp
 
 # https://squidfunk.github.io/mkdocs-material/setup/setting-up-social-cards/#linux
 RUN sudo install-packages \
@@ -14,4 +22,5 @@ RUN sudo install-packages \
 COPY --from=docker/buildx-bin:latest /buildx /usr/libexec/docker/cli-plugins/docker-buildx
 
 # brew maintenance + install ShellCheck and Hadolint
+WORKDIR /home/gitpod
 RUN brew update && brew install hadolint shellcheck

.hadolint.yml

@@ -0,0 +1,3 @@
+ignored:
+  - DL3004
+failure-threshold: error