Google Cloud Container Builder with cache

Question

Let's say I have:

steps:
    - name: 'gcr.io/cloud-builders/gradle'
      entrypoint: 'bash'
      args: ['-c',
             'chmod +x ./gradlew && ./gradlew build']
    - name: 'gcr.io/cloud-builders/docker'
      args: ['build', '--tag', 'eu.gcr.io/my-app:$_BUILD_ID', '.']
images: ['eu.gcr.io/my-app:$_BUILD_ID']

Are there any ways to leave the gradle's cache for the future builds? Currently, it keeps downloading all dependencies each time.

Maybe I need to suppy a bucket storage and point GRADLE_USER_HOME to it?

Answer 1

Use Container Builder to separate building the application from building its runtime layer - split your image in a container with the dependencies and another container containing your app as described here. It's also using the JRE instead of the JDK at runtime, saving some extra space

cloudbuild.yaml:

steps:
- name: 'java:8'
  env: ['GRADLE_USER_HOME=cache']
  entrypoint: 'bash'
  args: ['-c',
         './gradlew gate-web:installDist -x test']

- name: 'gcr.io/cloud-builders/docker'
  args: ['build',
         '-t', 'gcr.io/$PROJECT_ID/$REPO_NAME:$COMMIT_SHA', 
         '-t', 'gcr.io/$PROJECT_ID/$REPO_NAME:latest',
         '-f', 'Dockerfile.slim',
         '.'
  ]
images:
- 'gcr.io/$PROJECT_ID/$REPO_NAME:$COMMIT_SHA'
- 'gcr.io/$PROJECT_ID/$REPO_NAME:latest'

Dockerfile.slim:

FROM openjdk:8u111-jre-alpine

COPY ./gate-web/build/install/gate /opt/gate

CMD ["/opt/gate/bin/gate"]

Answer 2

This is what I'm using for our staging build:

cloudbuild.yaml:

steps:
  # Get the saved global gradle cache from
  # Google Cloud Storage if it exists.
  - name: 'gcr.io/cloud-builders/gsutil'
    entrypoint: 'sh'
    args:
      - '-c'
      - |
        # Global
        if gsutil -q stat gs://${PROJECT_ID}_cloudbuild/gradle_global.tar.gz; then
          cd /
          gsutil cp gs://${PROJECT_ID}_cloudbuild/gradle_global.tar.gz gradle_global.tar.gz
          tar -xpzf gradle_global.tar.gz
        fi
    volumes:
      - name: 'gradle_global'
        path: /root/.gradle

  # Build the java package.
  - name: 'gcr.io/cloud-builders/gradle'
    entrypoint: 'sh'
    args:
      - '-c'
      - |
        # Build the gateway .war package.
        ./gradlew -Pprod -DskipTests clean bootRepackage

        # Move the files needed for the docker image
        # to the slim directory.
        mv ./build/libs/*.war ./app.war

        # Delete all files and folders in the current directory
        # except for the `app.war` and `Dockerfile`.
        find . -type d -exec rm -rf {}
        find . -type f -not -name 'app.war' -not -name 'Dockerfile' -delete
    volumes:
     - name: 'gradle_global'
       path: /root/.gradle

  # Save the global gradle cache to Google Cloud Storage
  - name: 'gcr.io/cloud-builders/gsutil'
    entrypoint: 'sh'
    args:
      - '-c'
      - |
        # Global
        echo 'Creating an archive of /root/.gradle directory'
        tar -cpzf gradle_global.tar.gz /root/.gradle/
        echo 'Saving archive to Cloud Storage'
        gsutil cp gradle_global.tar.gz gs://${PROJECT_ID}_cloudbuild/gradle_global.tar.gz
        # Cleaning up
        echo 'Deleting gradle*.tar.gz'
        rm -f gradle*.tar.gz
  volumes:
    - name: 'gradle_global'
      path: /root/.gradle

  - name: 'gcr.io/cloud-builders/docker'
    args: ['pull', 'asia.gcr.io/$PROJECT_ID/${IMAGE_NAME}:latest']

  # Build the gateway container image.
  - name: 'gcr.io/cloud-builders/docker'
    args:
      - 'build'
      - '-t'
      - 'asia.gcr.io/${PROJECT_ID}/${IMAGE_NAME}:${COMMIT_SHA}'
      - '-t'
      - 'asia.gcr.io/${PROJECT_ID}/${IMAGE_NAME}:latest'
      - '--cache-from'
      - 'asia.gcr.io/${PROJECT_ID}/${IMAGE_NAME}:latest'
      - '.'

images:
  - asia.gcr.io/${PROJECT_ID}/gateway:${COMMIT_SHA}
  - asia.gcr.io/${PROJECT_ID}/gateway:latest

I hope this helps.

Answer 3

See these community cache images. You'll just need to build and publish the save_cache and restore_cache images to your image repository before using them because I'm not aware of public images.

This will tar the .gradle/caches and .gradle/wrapper directories and store them in the specified bucket. I think you need to specify the --paths with absolute file references in order for them to be restored automatically to the same directory by restore_cache when it unzips the tar.

Here's my cloudbuild.yaml.

steps:
  - name: 'gcr.io/$PROJECT_ID/restore_cache'
    args:
      - '--bucket=gs://${PROJECT_ID}_cloudbuild/${_CACHE_BUCKET}'
      - '--key=${_CACHE_KEY}'
  - name: 'java:8'
    entrypoint: "bash"
    args:
      - '-c'
      - './gradlew build'
    env:
      - 'GRADLE_OPTS="-Dorg.gradle.daemon=false -Dkotlin.incremental=false"'
      - 'GRADLE_USER_HOME=${_GRADLE_USER_HOME}'
  - name: 'gcr.io/$PROJECT_ID/save_cache'
    args:
      - '--bucket=gs://${PROJECT_ID}_cloudbuild/${_CACHE_BUCKET}'
      - '--key=${_CACHE_KEY}'
      - '--path=${_GRADLE_USER_HOME}/caches'
      - '--path=${_GRADLE_USER_HOME}/wrapper'
substitutions:
  _CACHE_BUCKET: 'gradle_cache'
  _GRADLE_USER_HOME: '/workspace/.gradle'
  _CACHE_KEY: 'gradle-cache'

It's important that GRADLE_USER_HOME be in the default /workspace volume (or a custom volume) so that is is retained between the various cloud build steps (volumes are automatically copied from step to step).