GitHub Action to build and deploy Docker container to Google Compute Engine on master branch push

gcp-compute.yml

name: Build and Deploy to Google Compute Engine

on:
  push:
    branches:
    - master

env:
  PROJECT_ID: ${{ secrets.GCE_PROJECT }}
  GCE_IMAGE: ${{ secrets.GCE_IMAGE }}
  GCE_INSTANCE: ${{ secrets.GCE_INSTANCE }}
  GCE_INSTANCE_ZONE: ${{ secrets.GCE_INSTANCE_ZONE }}

jobs:
  setup-build-push-deploy:
    name: Setup, Build, Push, and Deploy
    runs-on: ubuntu-latest

    steps:
    - name: Checkout
      uses: actions/checkout@v2

    - name: Setup the GCloud CLI
      uses: google-github-actions/setup-gcloud@master
      with:
        version: '290.0.1'
        service_account_key: ${{ secrets.GCE_SA_KEY }}
        project_id: ${{ secrets.GCE_PROJECT }}

    - name: Configure Docker
      run: |-
        gcloud --quiet auth configure-docker

    - name: Build the image
      run: |-
        docker build --tag "gcr.io/$PROJECT_ID/$GCE_IMAGE:$GITHUB_SHA" .

    - name: Push the image to GCR
      run: |-
        docker push "gcr.io/$PROJECT_ID/$GCE_IMAGE:$GITHUB_SHA"

    - name: Delete old docker images from the instance
      run: |- 
        gcloud compute instances add-metadata "$GCE_INSTANCE" \
          --zone "$GCE_INSTANCE_ZONE" \
          --metadata startup-script="#! /bin/bash
          docker image prune -af"

    - name: Update the server container
      run: |-
        gcloud compute instances update-container "$GCE_INSTANCE" \
          --zone "$GCE_INSTANCE_ZONE" \
          --container-image "gcr.io/$PROJECT_ID/$GCE_IMAGE:$GITHUB_SHA"