CircleCI

Selective detects CircleCI automatically and reads the node index from parallelism. The orb fills in the pieces CircleCI doesn’t expose to the job directly.

Setup

Set SELECTIVE_API_KEY as an environment variable on the project or in a context. Then in the test job:

- setup-selective/init:
    actor: << pipeline.trigger_parameters.github_app.user_username >>
    run_id: << pipeline.id >>
    target_branch: main

- run: bundle exec selective rspec

Set parallelism on the job to the number of nodes you want; each node pulls from the same queue.

A working config is in the selective-ruby-rspec repository and the selective-ruby-minitest repository.

Notes

• run_id should stay the same across reruns of the same commit and change when a new commit is pushed. The pipeline id does that.
• target_branch is the branch the change will merge into. Selective uses it to order tests by the diff and, in selection mode, to decide what changed.

Daily map recording

Test selection needs a fresh map of which files each test executes. Add a pipeline parameter and pass it to the test job as SELECTIVE_TEST_MAP_RECORD:

parameters:
  record_map:
    type: boolean
    default: false

jobs:
  test:
    parallelism: 4
    environment:
      SELECTIVE_TEST_MAP_RECORD: << pipeline.parameters.record_map >>

Then create a scheduled pipeline in Project Settings → Triggers that runs daily on the default branch with record_map set to true. That run prints Recording a test map. See keeping the map fresh.

Warm-up

With test selection on, a job that tells Selective about the run as the workflow starts has the commit’s file tree, the map and the semantic decision ready before the test nodes connect. See warm-up.

jobs:
  selective-warmup:
    docker:
      - image: cimg/base:current
    steps:
      - run:
          name: Warm up Selective
          command: |
            curl -sS --max-time 20 -X POST https://app.selective.ci/warmup \
              -H "authorization: $SELECTIVE_API_KEY" -H "content-type: application/json" \
              -d "{\"sha\": \"$CIRCLE_SHA1\", \"git_repo_full_name\": \"$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME\", \"target_branch\": \"main\", \"branch\": \"$CIRCLE_BRANCH\"}" \
              || true

workflows:
  tests:
    jobs:
      - selective-warmup
      - test

Give it the same context or project variables as the test job. target_branch must be the same value as the orb’s target_branch, and there’s no base_sha because the runner doesn’t report one on CircleCI. The test job doesn’t requires: it, so both start together.