Lumitrace

See what your Ruby code actually did — per pull request.

Lumitrace instruments the lines a PR touches, records the expression values while your tests run, and posts a GitHub Check with a coverage summary and a link to a full HTML report overlaying those values on your code.

Add it to a workflow

Take your existing test workflow and add the highlighted lines — your test command stays exactly the same:

name: test
on: pull_request

permissions:
  checks: write
  contents: read
  id-token: write                          # upload the report (omit = PR check only)

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: ruby/setup-ruby@v1
        with: { bundler-cache: true }
      - uses: ko1/lumitrace-action/setup@v1
      - run: bundle exec rake test           # unchanged
      - uses: ko1/lumitrace-action/report@v1
        if: always()

Tests split across parallel jobs? See sharded test suites to merge them into one report.

Where results appear

One pull-request run surfaces in three places — each more detailed than the last:

① + ② are the PR check itself, posted with checks: write. ③ is optional: add id-token: write and the report is uploaded and linked from ②; without it, nothing is uploaded.

Hosted reports

• Public repos — reports are world-readable; no app install needed.
• Private repos free during beta · paid later — install the Lumitrace Reports app on the repo. Viewing then requires a GitHub login with access to it; private source and values never leak.
• Reports are kept for 7 days.

Example reports

• Default report — type and hit counts per line (collect-mode: types), the out-of-the-box behaviour.
• With recorded values — the actual values overlaid on each line (collect-mode: last).