glint/README.md

glint

Disclaimer: This tool was built through iterative AI-assisted development with Claude. It is experimental, incomplete, and not intended for production use. Coverage of GitLab CI keywords is best-effort and may lag behind GitLab's evolving spec. Use it at your own discretion — no correctness guarantees are made. Contributions and bug reports are welcome.

A local tool to validate and lint .gitlab-ci.yml pipelines without needing a GitLab server.

Features

• YAML validation — detects malformed pipeline files early
• Stage validation — every job's stage must be declared in stages
• extends: resolution — resolves single and multi-level template inheritance before linting, so derived jobs are evaluated against their fully merged definition
• needs: DAG validation — checks that needs: references exist, respect stage ordering, and contain no circular dependencies
• dependencies: validation — checks that artifact dependency references exist and are in earlier stages
• Keyword validation — validates constraints on when, parallel, retry, allow_failure, trigger, artifacts, cache, release, environment, coverage, rules, and more
• Remote project includes — fetches include: project: templates from the GitLab API so extends/needs can be validated against the full merged pipeline
• CI/CD catalog components — resolves include: component: references from the GitLab CI/CD Catalog; public components work without a token
• Deprecation warnings — flags only/except usage in favour of rules
• Local include resolution — include: local: entries are read from disk and recursively merged before linting, so multi-file pipelines are fully validated
• Extended variable declarations — variables: entries may use the {value, description, options} map form (GitLab CI 13.7+); default.image accepts both string and map form; rules.changes/rules.exists accept both list and {paths, compare_to} map form
• Graph output — glint graph prints a job tree (stages → jobs) to the terminal; glint graph includes emits a Mermaid include dependency diagram; glint graph pipeline renders a GitLab CI-style PNG/SVG
• Context simulation — pass --branch, --tag, or --source to glint check or glint graph to see which jobs would be active, manual, or skipped for a specific pipeline event; evaluates rules:if: expressions and only/except filters

See ROADMAP.md for planned improvements.

Requirements

• Go 1.21 or later
• Task (optional, for development tasks)

Installation

git clone https://git.k3nny.fr/glint
cd glint
go build -o glint ./cmd/glint/...

Or with Task:

task build

Usage

glint [OPTIONS] <COMMAND>

Commands:
  check    Lint a pipeline file — exits 0 (clean) or 1 (errors found)
  graph    Visualise the pipeline as a job tree or Mermaid graph

Run glint <command> --help for command-specific options and examples.

glint check

glint check .gitlab-ci.yml

Exits 0 when no errors are found, 1 when at least one error is reported.

Remote project includes

Pipelines that include templates from other GitLab projects are supported. Provide a token so glint can fetch them:

# personal access token (read_api scope)
GITLAB_TOKEN=glpat-xxxx glint check .gitlab-ci.yml

# CI/CD job token (when running inside a pipeline)
CI_JOB_TOKEN=$CI_JOB_TOKEN glint check .gitlab-ci.yml

# self-hosted GitLab
GITLAB_TOKEN=glpat-xxxx GITLAB_URL=https://gitlab.example.com glint check .gitlab-ci.yml

# or via flags
glint check --token glpat-xxxx --gitlab-url https://gitlab.example.com .gitlab-ci.yml

Project includes require a token; without one they are skipped with a warning and the rest of the pipeline is linted as-is.

Component includes (include: component: ...) attempt the fetch unauthenticated, so public CI/CD Catalog components work without a token. A warning is emitted if the fetch fails.

Token resolution order (first non-empty wins):

Source	Header used
--token flag / GITLAB_TOKEN	PRIVATE-TOKEN
CI_JOB_TOKEN	JOB-TOKEN
GITLAB_PRIVATE_TOKEN	PRIVATE-TOKEN

Instance URL resolution order: --gitlab-url flag → CI_SERVER_URL → GITLAB_URL → https://gitlab.com

Component reference format

<host>/<project-path>/<component-name>@<version>

gitlab.com/components/secret-detection/secret-detection@v0.1.0
gitlab.com/my-org/ci-catalog/lint@main
gitlab.example.com/platform/components/build@~latest

The component file is looked up in order:

1. templates/<component-name>.yml (single-file layout)
2. templates/<component-name>/template.yml (directory layout)

Component input parameters (with:) are not validated — they are resolved by GitLab at runtime. Jobs in fetched components may use $[[ inputs.xxx ]] placeholders in fields like stage; glint skips those fields rather than producing false positive errors.

glint graph

Visualise the pipeline. Without a mode word, prints a job tree and the include dependency graph separated by ---.

# Default: job tree + include dependency graph
glint graph .gitlab-ci.yml

# Job tree only (stages → jobs, like the tree command)
glint graph tree .gitlab-ci.yml

# Include dependency graph → Mermaid flowchart to stdout
glint graph includes .gitlab-ci.yml > includes.mmd

# GitLab-like pipeline layout → PNG (or SVG fallback) written to --out dir
glint graph pipeline .gitlab-ci.yml
# prints the output file path, e.g.: glint-out/pipeline-20260607-143022.png

# Mermaid to stdout + pipeline file path to stderr
glint graph all .gitlab-ci.yml > includes.mmd

# Custom output directory (pipeline mode)
glint graph pipeline --out /tmp/graphs .gitlab-ci.yml

Job tree (graph tree) — stages as branches, jobs as leaves. Jobs with when: manual, when: delayed, or trigger: are annotated in brackets.

Include graph (graph includes) — Mermaid flowchart written to stdout. Pipe to a .mmd file or paste into mermaid.live. One node per include entry, colour-coded by type:

• Orange (bold): the main pipeline file
• Purple: project: includes
• Green: component: includes
• Blue: local: includes
• Grey: remote: URL includes
• Light orange: GitLab-provided template: includes

Pipeline graph (graph pipeline) — GitLab CI-style SVG rendered to a timestamped file in the --out directory (default: glint-out/). Converted to PNG automatically when rsvg-convert, inkscape, or magick is available; falls back to SVG otherwise. Jobs are colour-coded by type:

• Blue (#1f75cb): regular jobs
• Orange (#fc6d26): when: manual jobs
• Purple (#6b4fbb): trigger: jobs
• Amber (#fca326): when: delayed jobs

DAG mode (job-to-job Bézier arrows) activates automatically when any job has a needs: list. Classic mode draws L-shaped or straight connectors between stage columns otherwise.

Context simulation

Pass --branch, --tag, or --source to glint check to see which jobs would run for a given pipeline event. The pipeline is still fully linted; context output is printed first.

# What runs on a push to develop?
glint check --branch develop .gitlab-ci.yml

# What runs when a v1.2.0 tag is pushed?
glint check --tag v1.2.0 .gitlab-ci.yml

# Merge request pipeline
glint check --source merge_request_event .gitlab-ci.yml

# Arbitrary variable overrides (repeatable)
glint check --branch main --var DEPLOY_ENV=production .gitlab-ci.yml

Evaluated:

• rules:if: — full expression language: ==, !=, =~, !~, &&, ||, !, (), $VAR, string literals, null
• only: / except: — ref keywords (branches, tags, merge_requests, schedules, …), branch name globs (feat/*), and /regex/ patterns

Not evaluated (no git tree at lint time): rules:changes:, rules:exists:. Rules without an if: clause always match.

Predefined variables set automatically by the shortcut flags:

Flag	Variables populated
--branch <name>	CI_COMMIT_BRANCH, CI_COMMIT_REF_NAME, CI_COMMIT_REF_SLUG, CI_PIPELINE_SOURCE=push
--tag <name>	CI_COMMIT_TAG, CI_COMMIT_REF_NAME, CI_COMMIT_REF_SLUG, CI_PIPELINE_SOURCE=push (clears CI_COMMIT_BRANCH)
--source <event>	CI_PIPELINE_SOURCE
--var KEY=VALUE	any variable; overrides shortcuts

Example output

# Clean pipeline, no context
OK: .gitlab-ci.yml — no issues found (5 jobs, 3 stages)

# With --branch develop context
Context: branch=develop, source=push

Active  (3): build, deploy-staging, test
Skipped (2): deploy-prod, release-notes

OK: .gitlab-ci.yml — no issues found (5 jobs, 3 stages)

# With --tag v1.0.0 context
Context: tag=v1.0.0, source=push

Active  (4): build, deploy-prod, release-notes, test
Skipped (1): deploy-staging

OK: .gitlab-ci.yml — no issues found (5 jobs, 3 stages)

# Pipeline with issues
[ERROR] job "deploy": stage "production" is not defined in 'stages'
[ERROR] job "test": needs unknown job "build-app"
[WARNING] job "old-job": 'only'/'except' are deprecated; prefer 'rules'

3 finding(s): 2 error(s)

Lint rules

Every finding includes a stable rule ID (e.g. GL003) that can be used to filter output or reference a specific check in documentation.

Pipeline-level

ID	Severity	Rule
GL002	ERROR	workflow.rules[*].when is not always or never
GL001	WARNING	No stages defined (GitLab falls back to default stages)

Job-level — structure

ID	Severity	Rule
GL003	ERROR	Job is missing required script (or run) — non-trigger, non-template jobs
GL004	ERROR	Job references a stage not declared in stages
GL005	ERROR	only and rules used together on the same job
GL006	ERROR	except and rules used together on the same job
GL007	WARNING	only/except used (deprecated, prefer rules)

Job-level — keyword constraints

ID	Severity	Rule
GL008	ERROR	when is not one of on_success, on_failure, always, manual, delayed, never
GL009	ERROR	when: delayed without start_in
GL010	ERROR	start_in set but when is not delayed
GL011	ERROR	parallel integer not in range 2–200, or map form missing matrix key
GL012	ERROR	retry integer not in range 0–2, or retry.max out of range
GL013	ERROR	retry.when contains an unrecognised failure type
GL014	ERROR	allow_failure is not a boolean or a map with exit_codes
GL015	ERROR	interruptible is not a boolean
GL016	ERROR	trigger job also has script
GL017	ERROR	trigger map missing project or include
GL018	ERROR	coverage is not a regex pattern wrapped in /
GL019	ERROR	release missing required tag_name, or is not a map
GL020	ERROR	environment.url set without environment.name, or invalid environment.action
GL021	ERROR	artifacts.when invalid, or artifacts.expose_as set without artifacts.paths
GL022	WARNING	pages job artifacts.paths does not include public
GL023	ERROR	cache.when or cache.policy has an invalid value
GL024	ERROR	rules[*].when is not one of the valid when values
GL025	ERROR	image map form missing name key
GL026	ERROR	inherit.default / inherit.variables is not a boolean or list

Cross-job graph

ID	Severity	Rule
GL027	ERROR/WARNING	needs: references a job that does not exist (WARNING when optional: true)
GL028	ERROR	needs: references a job in a later stage
GL029	ERROR	Circular dependency detected in needs: graph
GL030	ERROR	dependencies: references a job that does not exist
GL031	ERROR	dependencies: references a job in the same or a later stage

Expression validation

ID	Severity	Rule
GL032	WARNING	rules:if: references $VAR not declared in variables: (pipeline, job, or workflow:rules:variables:) — may be a false positive for variables set in GitLab CI/CD project settings

Hidden jobs (templates)

Jobs whose name starts with . are treated as reusable templates and skipped for most rules. This matches GitLab's own behaviour.

Development

This project uses Task as a task runner.

task              # list available tasks
task build        # compile the binary
task test         # run Go unit tests
task lint-go      # run go vet
task validate     # run the binary against all testdata fixtures
task ci           # full check: vet → test → build → validate
task build-windows  # cross-compile for Windows x64 (requires a tagged commit → glint-<tag>.exe)
task build-linux    # cross-compile for Linux x64 (requires a tagged commit → glint-<tag>-linux-amd64)
task clean        # remove build artifacts

Project structure

.
├── cmd/glint/     # CLI entrypoint
├── internal/
│   ├── cicontext/      # CI variable context, rules:if: evaluator, job reachability
│   ├── fetcher/        # GitLab API client (project include fetching)
│   ├── graph/          # Mermaid and SVG/PNG graph generators
│   ├── linter/         # lint rules and findings
│   ├── model/          # pipeline data structures and YAML parser
│   └── resolver/       # extends: resolution and project include merging
├── testdata/           # sample pipelines used for manual validation
├── Taskfile.yml
└── go.mod