ci: automatically build & push docker image to ghcr.io

.github/workflows/docker-publish.yaml

@@ -0,0 +1,97 @@
+name: Docker build & push to ghcr.io
+
+# 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:
+  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@v4
+
+      # 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@v3
+
+      # Set up BuildKit Docker container builder to be able to build
+      # multi-platform images and export cache
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      # 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@v3
+        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@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+
+      # 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@v5
+        with:
+          context: .
+          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:
+          # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
+          TAGS: ${{ steps.meta.outputs.tags }}
+          DIGEST: ${{ steps.build-and-push.outputs.digest }}
+        # This step uses the identity token to provision an ephemeral certificate
+        # against the sigstore community Fulcio instance.
+        run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.21.4 AS Build
+FROM golang AS Build
 WORKDIR /app
 COPY go.mod go.sum ./
 RUN go mod download
@@ -7,12 +7,13 @@ COPY cmd ./cmd
 COPY pkg ./pkg
 RUN CGO_ENABLED=0 GOOS=linux go build -o /gpodder2go
 
-FROM alpine:3.18.4
+FROM alpine
 RUN mkdir /data
 WORKDIR /data
 COPY entrypoint.sh /entrypoint.sh
-RUN chmod +x /data
+RUN chmod +x /data /entrypoint.sh
 COPY --from=Build /gpodder2go /gpodder2go
+
 EXPOSE 3005
 VOLUME /data
-CMD ["/entrypoint.sh"]
+ENTRYPOINT ["/entrypoint.sh"]

README.md

@@ -88,6 +88,36 @@ Add with:
 
 ### Docker
 
+```sh
+$ docker run -d \
+--name gpodder2go \
+-p 3005:3005 \
+-v <data_directory>:/data \
+oxtyped/gpodder2go:latest
+```
+
+With docker compose:
+
+```yaml
+version: '3'
+services:
+  gpodder2go:
+    image: oxtyped/gpodder2go:latest
+    ports:
+      - 3005:3005
+    volumes:
+      - ./gpodder2go:/data
+    restart: unless-stopped
+```
+
+To configure the server run
+
+```sh
+$ docker exec --it gpodder2go /gpodder2go ...
+```
+
+#### Build docker image from source
+
 Build with:
 
 ```