Gitlab CI

GitLab CI/CD Skill

Skill, CI/CD, GitLab, Pipelines

Context

Use this skill when designing or debugging GitLab CI/CD pipelines. This covers .gitlab-ci.yml configuration, GitLab Runners, pipeline stages, DAG (Directed Acyclic Graph) pipelines, merge request pipelines, include/extends patterns, and environment-based deployments. The AI will act as a specialist in GitLab CI idioms and best practices.

Variables

• {{pipeline_trigger}}: What triggers the pipeline (e.g., merge_request_event, push to main, schedule, manual).
• {{pipeline_goal}}: What the pipeline accomplishes (e.g., lint, test, build Docker image, deploy to Kubernetes).
• {{tech_stack}}: Language/framework/tooling (e.g., Python 3.11, Docker, Helm, AWS).
• {{runner_type}}: Runner executor type (e.g., docker, shell, kubernetes, GitLab-hosted SaaS runner).
• {{environment}}: Target deployment environment (e.g., production on GKE, staging on a VPS).

Prompt

Adopt the persona of a Senior GitLab CI/CD Engineer. I need to design the following pipeline:

Goal: {{pipeline_goal}}

Trigger: {{pipeline_trigger}}

Tech Stack: {{tech_stack}}

Runner Type: {{runner_type}}

Target Environment: {{environment}}

Design the `.gitlab-ci.yml` configuration adhering to these standards:

1. **Pipeline Structure:** Define clear `stages`. Use `needs:` for DAG parallelism where jobs don't require a full prior stage to complete. Prefer `extends:` and `!reference` over copy-pasting job templates.
2. **Security:** Use CI/CD Variables (masked and protected) for all secrets. Use `environment:` with protected branches for production. Apply `rules:` carefully to prevent accidental production deployments from feature branches. Never echo secrets in logs.
3. **Efficiency:** Use `cache:` with a keyed strategy (e.g., `$CI_COMMIT_REF_SLUG`) to share dependencies across stages. Use `artifacts:` with `expire_in` to pass build outputs between jobs without redundant builds.
4. **Reusability:** Modularize with `include: - project:` or `include: - local:` to pull shared job templates. Use `trigger:` for multi-project pipelines if applicable.
5. **Merge Request Workflows:** Include a `rules: - if: $CI_PIPELINE_SOURCE == "merge_request_event"` block for MR-only jobs like linting and short tests.
6. **Observability:** Use `after_script:` for cleanup and failure notifications. Tag jobs with appropriate `tags:` to route them to the correct runner.

Provide the full `.gitlab-ci.yml` with comments on every structural and security decision.

Example Usage

Input:

Adopt the persona of a Senior GitLab CI/CD Engineer. I need to design the following pipeline:

Goal: Run lint and tests on MRs, build a Docker image and push to GitLab Container Registry on main, deploy to staging automatically and production manually.

Trigger: merge_request_event and push to main

Tech Stack: Python 3.11 (FastAPI), Docker, GitLab Container Registry, Kubernetes

Runner Type: GitLab-hosted SaaS runner (docker executor)

Target Environment: Staging (auto) and Production (manual) on GKE

Design the `.gitlab-ci.yml` configuration adhering to these standards:
[...rest of prompt...]

Expected Output: A complete .gitlab-ci.yml with:

• stages: [lint, test, build, deploy-staging, deploy-production]
• DAG needs: so build starts as soon as test finishes, not waiting for all of test stage
• Docker image tagged with $CI_COMMIT_SHORT_SHA for immutability
• environment: production with when: manual and protected branch rules
• cache: keyed on $CI_COMMIT_REF_SLUG for pip dependencies