GCP Build Image Action

A GitHub Action to build and push container images to Google Cloud using Cloud Build.

Features

• 🚀 Build container images using Google Cloud Build
• 📦 Uses Cloud Native Buildpacks for automatic image creation or custom Dockerfiles
• 🔧 Configurable project, region, and build settings
• ⚡ Simple and lightweight composite action

Prerequisites

Before using this action, ensure you have:

1. Google Cloud authentication set up in your workflow (using google-github-actions/auth or similar)
2. Cloud Build API enabled in your Google Cloud project
3. Artifact Registry (or Container Registry) repository created for storing images
4. Proper IAM permissions for the service account:
   • Cloud Build Editor or Cloud Build Service Account
   • Artifact Registry Writer (if using Artifact Registry)

Usage

Basic Example

name: Build and Deploy
on:
  push:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        
      - name: Authenticate to Google Cloud
        uses: google-github-actions/auth@v1
        with:
          credentials_json: ${{ secrets.GCP_SA_KEY }}
          
      - name: Set up Cloud SDK
        uses: google-github-actions/setup-gcloud@v1
        
      - name: Build image
        uses: discue/gcp-build-image-action@v1
        with:
          image: 'europe-west3-docker.pkg.dev/my-project/my-repo/my-app'
          project: 'my-project'
          region: 'europe-west3'

Advanced Example

      - name: Build image with custom settings
        uses: discue/gcp-build-image-action@v1
        with:
          image: 'europe-west3-docker.pkg.dev/my-project/my-repo/my-app:${{ github.sha }}'
          project: 'my-project'
          region: 'europe-west3'
          source: './src'
          quiet: 'false'

Inputs

Input	Description	Required	Default
image	The full image URL to build (e.g., europe-west3-docker.pkg.dev/project/repository/image)	Yes	-
project	Google Cloud project ID	No	Uses gcloud default
region	Google Cloud region for builds	No	Uses gcloud default
source	Source directory to build from	No	.
quiet	Run in quiet mode	No	true
builder	Build method: buildpack (uses Cloud Native Buildpacks) or dockerfile (uses your Dockerfile). If not set, the action will auto-detect: uses Dockerfile if present in the source directory, otherwise uses buildpack.	No	Auto-detect

Outputs

Output	Description
image-url	The built image URL

Authentication

This action requires Google Cloud authentication. The recommended approach is to use Workload Identity Federation:

- name: Authenticate to Google Cloud
  uses: google-github-actions/auth@v1
  with:
    workload_identity_provider: 'projects/123456789/locations/global/workloadIdentityPools/my-pool/providers/my-provider'
    service_account: '[email protected]'

Alternatively, you can use a service account key (less secure):

- name: Authenticate to Google Cloud
  uses: google-github-actions/auth@v1
  with:
    credentials_json: ${{ secrets.GCP_SA_KEY }}

Required IAM Permissions

The service account used must have the following permissions:

• cloudbuild.builds.create
• cloudbuild.builds.get
• artifactregistry.repositories.uploadArtifacts (if using Artifact Registry)
• storage.objects.create (for build logs and cache)

These are typically provided by the following predefined roles:

• roles/cloudbuild.builds.builder
• roles/artifactregistry.writer

Example Workflow

name: Build and Deploy to Cloud Run

on:
  push:
    branches: [main]

env:
  PROJECT_ID: my-project
  REGION: europe-west3
  REPOSITORY: my-repo
  SERVICE: my-service

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Authenticate to Google Cloud
        uses: google-github-actions/auth@v1
        with:
          workload_identity_provider: ${{ secrets.WIF_PROVIDER }}
          service_account: ${{ secrets.WIF_SERVICE_ACCOUNT }}

      - name: Set up Cloud SDK
        uses: google-github-actions/setup-gcloud@v1

      - name: Build image
        id: build
        uses: discue/gcp-build-image-action@v1
        with:
          image: '${{ env.REGION }}-docker.pkg.dev/${{ env.PROJECT_ID }}/${{ env.REPOSITORY }}/${{ env.SERVICE }}:${{ github.sha }}'
          project: ${{ env.PROJECT_ID }}
          region: ${{ env.REGION }}

      - name: Deploy to Cloud Run
        run: |
          gcloud run deploy ${{ env.SERVICE }} \
            --image ${{ steps.build.outputs.image-url }} \
            --region ${{ env.REGION }} \
            --platform managed \
            --allow-unauthenticated

Error Handling

The action will fail if:

• Google Cloud authentication is not set up
• The specified project or region is invalid
• Cloud Build API is not enabled
• Insufficient IAM permissions
• Invalid image URL format
• Source directory doesn't exist

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.