Add support for PR base images.

Author: zenoando

.github/workflows/build.yaml

@@ -2,6 +2,8 @@ name: Build and publish
 
 on:
   pull_request:
+    types: 
+      - closed
     branches:
       - main
   release:

.github/workflows/pr-image.yaml

@@ -0,0 +1,32 @@
+name: Build and push image from PR
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  build:
+    name: Build and push image from PR
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Log in to ghcr
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build the image
+        run: make build
+
+      - name: Push PR image to the registry
+        run: make pr-image
+        env:
+          TAG: ${{ github.head_ref }}

Makefile

@@ -12,5 +12,9 @@ publish:
 	@test -n "${TAG}" || ( echo "TAG environment variable must be set" && return 1 )
 	./scripts/publish.sh $(IMAGE_NAME) ${TAG}
 
+pr-image:
+	@test -n "${TAG}" || ( echo "TAG environment variable must be set" && return 1 )
+	./scripts/pr-image.sh $(IMAGE_NAME) ${TAG}
+
 help:
 	@sed -ne '/@sed/!s/## //p' $(MAKEFILE_LIST)

scripts/pr-image.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+# Push images built off a PR to Github Container Registry
+
+set -e
+
+if [ "$#" -ne 2 ]; then
+    >&2 echo "Usage: $(basename $0) <image-name> <branch-tag>"
+    exit 1
+fi
+
+IMAGE_NAME="$1"
+BRANCH=$(echo "${2}" | sed 's/\//-/g')
+
+echo "🏷️ Setting tags for image '${IMAGE_NAME}:${BRANCH}-prbase"
+docker tag "${IMAGE_NAME}:base" "${IMAGE_NAME}:${BRANCH}-prbase"
+
+echo "📤 Pushing '${IMAGE_NAME}:${BRANCH}-prbase'"
+docker push "${IMAGE_NAME}:${BRANCH}-prbase"