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analysing-ci-failures

DevOps & Security
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Analysing GitHub Actions CI failures from a run URL. Use when the user pastes a GitHub CI run or job URL and wants to understand why it failed and how to reproduce locally.

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Source SKILL.md: https://github.com/golemcloud/golem/blob/HEAD/.agents/skills/analysing-ci-failures/SKILL.md

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Analysing CI Failures

Diagnose GitHub Actions CI failures by downloading logs and CTRF test reports, then providing a summary of what failed and how to reproduce it locally.

Step 1: Parse the URL

The user provides a GitHub Actions URL in one of these forms:

  • Job URL: https://github.com/golemcloud/golem/actions/runs/<run_id>/job/<job_id>?pr=<pr>
  • Run URL: https://github.com/golemcloud/golem/actions/runs/<run_id>?pr=<pr>

Extract the run_id and job_id (if present) from the URL.

Step 2: Download the Job Log

Use gh to download the full log for the failed job and save it to a temp file:

# If a specific job_id is available:
gh run view <run_id> --repo golemcloud/golem --log --job <job_id> > tmp/ci_log.txt 2>&1

# If only the run_id is available, first list the jobs to find the failed one:
gh run view <run_id> --repo golemcloud/golem --json jobs --jq '.jobs[] | select(.conclusion == "failure") | .databaseId'
# Then download the log for the failed job:
gh run view <run_id> --repo golemcloud/golem --log --job <failed_job_id> > tmp/ci_log.txt 2>&1

Step 3: Download CTRF Reports (if available)

CTRF (Common Test Report Format) JSON reports are attached as artifacts to the CI run summary page. Download them:

# List available artifacts for the run:
gh run view <run_id> --repo golemcloud/golem --json artifacts --jq '.artifacts[].name'

# Download CTRF artifacts (names typically contain "ctrf" or "test-report"):
gh run download <run_id> --repo golemcloud/golem --pattern '*ctrf*' --dir tmp/ctrf_reports/

If CTRF artifacts exist, parse the JSON files to extract failed test names, error messages, and stack traces. CTRF files have this structure:

{
  "results": {
    "summary": { "tests": 100, "passed": 98, "failed": 2 },
    "tests": [
      {
        "name": "test_name",
        "status": "failed",
        "message": "error message",
        "trace": "stack trace"
      }
    ]
  }
}

Filter for tests with "status": "failed" to find the failures.

Step 4: Analyse the Log

Search the downloaded log file for failure indicators:

grep -n "FAILED" tmp/ci_log.txt
grep -n "error\[" tmp/ci_log.txt
grep -n "panic" tmp/ci_log.txt
grep -n "timed out" tmp/ci_log.txt
grep -n "test result:" tmp/ci_log.txt

Look for:

  • Compilation errors: error[E...] lines with file paths and error descriptions
  • Test failures: FAILED test names, assertion messages, panics
  • Timeouts: Tests that exceeded their time limit
  • Infrastructure issues: Docker failures, network errors, resource exhaustion

Step 5: Provide a Summary

Present the findings to the user including:

  1. What failed: The specific test(s) or build step(s) that failed
  2. Error details: The error messages, assertion failures, or panic messages
  3. Root cause hypothesis: What likely caused the failure based on the logs
  4. How to reproduce locally: The exact command to run the failing test(s):
# For a specific failing test:
cargo test -p <crate> -- <test_name> --nocapture --report-time

# For the full test suite that failed:
cargo make <test-command>  # e.g., worker-executor-tests, integration-tests

Refer to the testing skill's table for the correct cargo make command based on the type of test that failed.