gitlab-ci-linter

name	gitlab-ci-linter
description	Lint and validate GitLab CI/CD pipeline YAML files (.gitlab-ci.yml) for syntax errors, security issues, deprecated patterns, and best practices. Use when asked to lint, validate, audit, or check GitLab CI pipelines, .gitlab-ci.yml files, or CI/CD configurations for GitLab. Triggers on "lint gitlab", "check pipeline", "validate CI", "audit gitlab-ci", "pipeline issues", "gitlab security".

Dependency Source Review

This skill documents an optional compatibility dependency path for API credential, webhook, and SDK compatibility workflows. Treat scripts/_setup_deps.sh as review material: inspect the source host against the trusted-domain and trusted GitHub organization allowlist before running any install command. It is not required for ordinary integration or webhook requests.

GitLab CI Linter

Lint GitLab CI/CD pipeline files for syntax errors, security issues, deprecated patterns, and best practices violations.

Commands

All commands use the bundled Python script at scripts/gitlab_ci_linter.py.

1. Lint a pipeline file

python3 scripts/gitlab_ci_linter.py lint <file-or-directory> [--strict] [--format text|json|markdown]

Runs all lint rules against one or more .gitlab-ci.yml files. If given a directory, scans for *.yml and *.yaml files recursively.

Flags:

• --strict -- exit code 1 on any warning (not just errors)
• --format -- output format: text (default), json, markdown

2. Audit for security issues

python3 scripts/gitlab_ci_linter.py security <file> [--format text|json|markdown]

Focused security audit: hardcoded secrets, unprotected variables, privileged runners, insecure Docker image tags, security jobs with allow_failure.

3. Inspect stages

python3 scripts/gitlab_ci_linter.py stages <file> [--format text|json|markdown]

Show defined stages and which jobs map to each stage. Flags undefined or unused stages.

4. Validate pipeline structure

python3 scripts/gitlab_ci_linter.py validate <file> [--format text|json|markdown]

Structural validation only: required keys, stage definitions, job keywords, dependency graph (circular needs:, missing refs).

Lint Rules (24 total)

Syntax & Structure (8 rules)

1. missing-stages -- No stages: definition
2. undefined-stage -- Job uses stage not in stages: list
3. empty-job -- Job has no script: section
4. invalid-job-name -- Job name starts with . but is not used as a template
5. missing-script -- Job without script:, before_script:, or trigger:
6. circular-needs -- Circular dependency in needs: graph
7. duplicate-job -- Duplicate job names (YAML parser collapses them)
8. invalid-keyword -- Unknown top-level or job-level keyword

Security (6 rules)

9. hardcoded-secret -- Passwords, tokens, keys in plain text
10. unprotected-variable -- Sensitive-looking variable not using $CI_* references
11. allow-failure-security -- Security-related job with allow_failure: true
12. privileged-runner -- tags: requesting privileged runners
13. unmasked-variable -- Variable looks sensitive but not described as masked
14. insecure-image -- Using :latest tag for Docker images

Best Practices (10 rules)

15. missing-retry -- No retry: on deploy/test jobs
16. missing-timeout -- No timeout: specified
17. no-cache-key -- cache: without explicit key:
18. broad-artifacts -- Overly broad artifacts: paths: patterns
19. missing-rules -- Job without rules: or only:/except:
20. deprecated-only-except -- Using only:/except: instead of rules:
21. long-script -- script: block exceeds 30 lines
22. missing-interruptible -- Long-running job without interruptible:
23. no-coverage-regex -- Test job without coverage: regex
24. missing-when -- No when: in rules: entries

Output Formats

Text (default)

.gitlab-ci.yml:12 error [missing-script] Job 'deploy' has no script:, before_script:, or trigger:
.gitlab-ci.yml:25 warning [missing-timeout] Job 'test' has no timeout: specified
.gitlab-ci.yml:31 info [deprecated-only-except] Job 'build' uses only:/except: instead of rules:

3 issues (1 error, 2 warnings)

JSON

{
  "file": ".gitlab-ci.yml",
  "issues": [...],
  "summary": {"errors": 1, "warnings": 2, "info": 0}
}

Markdown

Summary table with severity, rule, location, and message.

CI Integration

# .gitlab-ci.yml
lint-pipeline:
  stage: test
  script:
    - python3 scripts/gitlab_ci_linter.py lint .gitlab-ci.yml --strict

Exit codes: 0 = clean, 1 = errors found (or warnings in --strict mode).