Early success in a build

Build Environment
2

I have a similar workflow that builds multiple Docker images from a monorepo. The solution I’ve come up with is to wrap that logic in a shell script which exits 0 if either the image is built or its not built because the relevant files did not change based on git diff.

The approach was to create a logical_changes.sh which parses the git refs in CIRCLE_COMPARE_URL to determine the appropriate git diff ref1 ref2 --name-only command to run. Then, for each logical change, which equates to a need to build a Docker image, that script exports values like CI_IMAGE_A_CHANGED or CI_IMAGE_B_CHANGED.

FInally, I have shell scripts for each docker build which source logical_changes.sh, test the value of the relevant CI_IMAGE_*_CHANGED then either exit 0 early or run the docker build.

Each Docker build in my workflow ends up looking something like:

build_and_push_foo_release:
  working_directory: /root/project
  docker:
    - image: foo/circleci-builder
  steps:
    - attach_workspace:
        at: /root/project
    - setup_remote_docker:
        version: 17.05.0-ce
    - run:
        name: Build Foo Docker Image
        command: |
          cd /root/project/
          TAG=$CIRCLE_BRANCH-$CIRCLE_SHA1
          ci/build_foo_docker_image.sh ecom/ $TAG

So, in cases where no build and push is necessary, those builds take about 60-90 seconds to setup_remote_docker, then exit when the script recognizes it need not build an image.

However, like you I recognize that ideally we could short-circuit earlier potentially using a when condition on the steps in a build that could test the value of an environment variable.

1 Like