CI/CD components

Version history

A CI/CD component is a reusable single pipeline configuration unit. Use them to compose an entire pipeline configuration or a small part of a larger pipeline.

A component can take input parameters.

CI/CD components are similar to the other kinds of configuration added with the include keyword, but have several advantages:

  • Components can be released and used with a specific version.
  • Multiple components can be defined in the same project and versioned together.
  • Components are discoverable in the CI/CD Catalog.

Component project

A component project is a GitLab project with a repository that hosts one or more components. All components in the project are versioned together.

If a component requires different versioning from other components, the component should be moved to a dedicated component project.

One component repository can have a maximum of 10 components.

Create a component project

To create a component project, you must:

  1. Create a new project with a README.md file.
  2. Add a YAML configuration file for each component, following the required directory structure.

    For example:

    spec:
      inputs:
        stage:
          default: test
    ---
    component-job:
      script: echo job 1
      stage: $[[ inputs.stage ]]
    

Directory structure

The repository must contain:

  • A README.md Markdown file documenting the details of all the components in the repository.
  • A top level templates/ directory that contains all the component configurations. You can define components in this directory:
    • In single files ending in .yml for each component, like templates/secret-detection.yml.
    • In sub-directories containing template.yml files as entry points, for components that bundle together multiple related files. For example, templates/secret-detection/template.yml.

Configure the project’s .gitlab-ci.yml to test the components and release new versions.

For example, if the project contains a single component, the directory structure should be similar to:

├── templates/
│   └── secret-detection.yml
├── README.md
└── .gitlab-ci.yml

If the project contains multiple components, then the directory structure should be similar to:

├── templates/
│   ├── all-scans.yml
│   └── secret-detection/
│       ├── template.yml
│       ├── Dockerfile
│       └── test.sh
├── README.md
└── .gitlab-ci.yml

In this example:

  • The all-scans component configuration is defined in a single file.
  • The secret-detection component configuration contains multiple files in a directory.

Use a component

You can use a component in a CI/CD configuration with the include: component keyword. The component is identified by a unique address formatted as <fully-qualified-domain-name>/<project-path>/<component-name>@<specific-version>.

For example:

include:
  - component: gitlab.example.com/my-org/security-components/secret-detection@1.0
    inputs:
      stage: build

In this example:

  • gitlab.example.com is the Fully Qualified Domain Name (FQDN) matching the GitLab host. You can only reference components in the same GitLab instance as your project.
  • my-org/security-components is the full path of the project containing the component.
  • secret-detection is the component name that is defined as either a single file templates/secret-detection.yml or as a directory templates/secret-detection/ containing a template.yml.
  • 1.0 is the version of the component. In order of highest priority first, the version can be:
    • A branch name, for example main.
    • A commit SHA, for example e3262fdd0914fa823210cdb79a8c421e2cef79d8.
    • A tag, for example: 1.0. If a tag and branch exist with the same name, the tag takes precedence over the branch. If a tag and commit SHA exist with the same name, the commit SHA takes precedence over the tag.
    • ~latest, which is a special version that always points to the most recent release published in the CI/CD Catalog.
note
The ~latest version keyword always returns the most recent published release, not the release with the latest semantic version. For example, if you first release 2.0.0, and later release a patch fix like 1.5.1, then ~latest returns the 1.5.1 release. Issue #427286 proposes to change this behavior.

CI/CD Catalog

Version history

The CI/CD Catalog is a list of projects with published CI/CD components you can use to extend your CI/CD workflow.

Anyone can add a component project to the CI/CD Catalog, or contribute to an existing project to improve the available components.

View the CI/CD Catalog

To access the CI/CD Catalog and view the published components that are available to you:

  1. On the left sidebar, select Search or go to.
  2. Select Explore.
  3. Select CI/CD Catalog.

Alternatively, if you are already in the pipeline editor in your project, you can select Browse CI/CD Catalog.

note
Only public and internal projects are discoverable in the CI/CD Catalog.

Publish a component project

To publish a component project in the CI/CD catalog, you must:

  1. Set the project as a catalog resource.
  2. Publish a new release.

Set a component project as a catalog resource

To make published versions of a component project visible in the CI/CD catalog, you must set the project as a catalog resource:

  1. On the left sidebar, select Search or go to and find your project.
  2. On the left sidebar, select Settings > General.
  3. Expand Visibility, project features, permissions.
  4. Scroll down to CI/CD Catalog resource and select the toggle to mark the project as a catalog resource.

Publish a new release

Components defined in a component project can be used immediately and don’t require to be published in the CI/CD catalog. However, having the component project published in the catalog makes it discoverable to other users.

After the project is set as a catalog resource, add a job to the project’s .gitlab-ci.yml file that creates a release using the release keyword.

For example:

create-release:
  stage: deploy
  image: registry.gitlab.com/gitlab-org/release-cli:latest
  script: echo "Creating release $CI_COMMIT_TAG"
  release:
    tag_name: $CI_COMMIT_TAG
    description: "Release $CI_COMMIT_TAG of components in $CI_PROJECT_PATH"

The release fails if the project is missing:

  • The project description, to display in the catalog list.
  • A README.md file in the root directory for the commit SHA of the tag being released.
  • Any component in the templates/ directory for the commit SHA of the tag being released.

Create a new tag for the release, which should trigger a tag pipeline that contains the job responsible that creates the release. You should configure the tag pipeline to test the components before running the release job.

The release is created and the new version is published to the CI/CD catalog only if:

note
If you disable catalog resource setting, the component project and all versions are removed from the catalog. To publish it again, you must re-enable the setting and release a new version.

Best practices

This section describes some best practices for creating high quality component projects.

Test the component

Testing CI/CD components as part of the development workflow is strongly recommended and helps ensure consistent behavior.

Test changes in a CI/CD pipeline (like any other project) by creating a .gitlab-ci.yml in the root directory. Make sure to test both the behavior and potential side-effects of the component. You can use the GitLab API if needed.

For example:

include:
  # include the component located in the current project from the current SHA
  - component: gitlab.com/$CI_PROJECT_PATH/my-component@$CI_COMMIT_SHA
    inputs:
      stage: build

stages: [build, test, release]

# Expect `component-job` is added.
# This example tests that the included component works as expected.
# You can inspect data generated by the component, use GitLab API endpoints or third-party tools.
ensure-job-added:
  stage: test
  image: badouralix/curl-jq
  script:
    - |
      route="https://gitlab.com/api/v4/projects/$CI_PROJECT_ID/pipelines/$CI_PIPELINE_ID/jobs"
      count=`curl --silent --header "PRIVATE-TOKEN: $API_TOKEN" $route | jq 'map(select(.name | contains("component-job"))) | length'`
      if [ "$count" != "1" ]; then
        exit 1
      fi

# If we are tagging a release with a semantic version and all previous checks succeeded,
# we proceed with creating a release automatically.
create-release:
  stage: release
  image: registry.gitlab.com/gitlab-org/release-cli:latest
  rules:
    - if: $CI_COMMIT_TAG =~ /\d+/
  script: echo "Creating release $CI_COMMIT_TAG"
  release:
    tag_name: $CI_COMMIT_TAG
    description: "Release $CI_COMMIT_TAG of components repository $CI_PROJECT_PATH"

After committing and pushing changes, the pipeline tests the component, then releases the tag it if the test passes.

Avoid using global keywords

Avoid using global keywords in a component. Using these keywords in a component affects all jobs in a pipeline, including jobs directly defined in the main .gitlab-ci.yml or in other included components.

As an alternative to global keywords, instead:

  • Add the configuration directly to each job, even if it creates some duplication in the component configuration.
  • Use the extends keyword in the component, but use unique names that reduce the risk of naming conflicts when the component is merged into the configuration.

For example, using the default keyword is not recommended:

# Not recommended
default:
  image: ruby:3.0

rspec-1:
  script: bundle exec rspec dir1/

rspec-2:
  script: bundle exec rspec dir2/

Instead, you can:

  • Add the configuration to each job:

    rspec-1:
      image: ruby:3.0
      script: bundle exec rspec dir1/
    
    rspec-2:
      image: ruby:3.0
      script: bundle exec rspec dir2/
    
  • Use extends to reuse configuration:

    .rspec-image:
      image: ruby:3.0
    
    rspec-1:
      extends:
        - .rspec-image
      script: bundle exec rspec dir1/
    
    rspec-2:
      extends:
        - .rspec-image
      script: bundle exec rspec dir2/
    

Replace hard-coded values with inputs

Avoid hard-coding values in CI/CD components. Hard-coded values might force component users to need to review the component’s internal details and adapt their pipeline to work with the component.

A common keyword with problematic hard-coded values is stage. If a component job’s stage is set to a specific value, the pipeline using the component must define the exact same stage. Additionally, if the component user wants to use a different stage, they must override the configuration.

The preferred method is to use the input keyword. The component user can specify the exact value they need.

For example:

  • In the component configuration:

    spec:
      inputs:
        stage:
          default: test
    ---
    unit-test:
      stage: $[[ inputs.stage ]]
      script: echo unit tests
    
    integration-test:
      stage: $[[ inputs.stage ]]
      script: echo integration tests
    
  • In the project using the component:

    include:
      - component: gitlab.com/gitlab-org/ruby-test@1.0
        inputs:
          stage: verify
    
    stages: [verify, deploy]
    

Replace custom CI/CD variables with inputs

When using CI/CD variables in a component, evaluate if the inputs keyword should be used instead. Avoid requiring a user to define custom variables to change a component’s behavior. You should try to use inputs for any component customization.

Inputs are explicitly defined in the component’s specs, and are better validated than variables. For example, if a required input is not passed to the component, GitLab returns a pipeline error. By contrast, if a variable is not defined, its value is empty, and there is no error.

For example, use inputs instead of variables to let users change a scanner’s output format:

  • In the component configuration:

    spec:
      inputs:
        scanner-output:
          default: json
    ---
    my-scanner:
      script: my-scan --output $[[ inputs.scanner-output ]]
    
  • In the project using the component:

    include:
      - component: gitlab.example.com/my-scanner@1.0
        inputs:
          scanner-output: yaml
    

In other cases, CI/CD variables are still preferred, including:

Use semantic versioning

When tagging and releasing new versions of components, you should use semantic versioning. Semantic versioning is the standard for communicating that a change is a major, minor, patch, or other kind of change.

You should use at least the major.minor format, as this is widely understood. For example, 2.0 or 2.1.

Other examples of semantic versioning:

  • 1.0.0
  • 2.1.3
  • 1.0.0-alpha
  • 3.0.0-rc1

Convert a CI/CD template to a component

Any existing CI/CD template that you use in projects by using the include: syntax can be converted to a CI/CD component:

  1. Decide if you want the component to be part of an existing component project to be grouped with other components, or create a new component project.
  2. Create a YAML file in the component project according to the expected directory structure.
  3. Copy the content of the original template YAML file into the new component YAML file.
  4. Refactor the new component’s configuration to:
  5. Leverage the .gitlab-ci.yml in the components repository to test changes to the component.
  6. Tag and release the component.

Troubleshooting

content not found message

You might receive an error message similar to the following when using the ~latest version qualifier to reference a component hosted by a catalog resource:

This GitLab CI configuration is invalid: component 'gitlab.com/my-namespace/my-project/my-component@~latest' - content not found`

The ~latest behavior was updated in GitLab 16.7. It now refers to the latest published version of the catalog resource. To resolve this issue, create a new release.