path: root/doc/ci/components/index.md

---
stage: Verify
group: Pipeline Authoring
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://handbook.gitlab.com/handbook/product/ux/technical-writing/#assignments
---

# CI/CD components **(FREE ALL BETA)**

> - Introduced as an [experimental feature](../../policy/experiment-beta-support.md) in GitLab 16.0, [with a flag](../../administration/feature_flags.md) named `ci_namespace_catalog_experimental`. Disabled by default.
> - [Enabled on GitLab.com and self-managed](https://gitlab.com/groups/gitlab-org/-/epics/9897) in GitLab 16.2.
> - [Feature flag `ci_namespace_catalog_experimental` removed](https://gitlab.com/gitlab-org/gitlab/-/issues/394772) in GitLab 16.3.
> - [Moved](https://gitlab.com/gitlab-com/www-gitlab-com/-/merge_requests/130824) to [Beta status](../../policy/experiment-beta-support.md) in GitLab 16.6.

A CI/CD component is a reusable single pipeline configuration unit. Use components
to create a small part of a larger pipeline, or even to compose a complete pipeline configuration.

A component can be configured with [input parameters](../yaml/inputs.md) for more
dynamic behavior.

CI/CD components are similar to the other kinds of [configuration added with the `include` keyword](../yaml/includes.md),
but have several advantages:

- Components can be listed in the [CI/CD Catalog](#cicd-catalog).
- Components can be released and used with a specific version.
- Multiple components can be defined in the same project and versioned together.

Instead of creating your own components, you can also search for published components
that have the functionality you need in the [CI/CD Catalog](#cicd-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, with a maximum of 10 components per project.

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

### Create a component project

To create a component project, you must:

1. [Create a new project](../../user/project/index.md#create-a-blank-project) with a `README.md` file.
1. Add a YAML configuration file for each component, following the [required directory structure](#directory-structure).
   For example:

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

You can [use the component](#use-a-component) immediately, but you might want to consider
publishing the component to the [CI/CD catalog](#cicd-catalog).

### 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`.

You should also:

- Configure the project's `.gitlab-ci.yml` to [test the components](#test-the-component)
  and [release new versions](#publish-a-new-release).
- Add a `LICENSE.md` file with a license of your choice that covers the usage of your component.
  For example the [MIT](https://opensource.org/license/mit/) or [Apache 2.0](https://www.apache.org/licenses/LICENSE-2.0#apply)
  open source licenses.

For example:

- If the project contains a single component, the directory structure should be similar to:

  ```plaintext
  ├── templates/
  │   └── my-component.yml
  ├── LICENSE.md
  ├── README.md
  └── .gitlab-ci.yml
  ```

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

  ```plaintext
  ├── templates/
  │   ├── my-simple-component.yml
  │   └── my-complex-component/
  │       ├── template.yml
  │       ├── Dockerfile
  │       └── test.sh
  ├── LICENSE.md
  ├── README.md
  └── .gitlab-ci.yml
  ```

  In this example:

  - The `my-simple-component` component's configuration is defined in a single file.
  - The `my-complex-component` component's configuration contains multiple files in a directory.

## Use a component

To add a component to a project's CI/CD configuration, use the [`include: component`](../yaml/index.md#includecomponent)
keyword. The component reference is formatted as `<fully-qualified-domain-name>/<project-path>/<component-name>@<specific-version>`,
for example:

```yaml
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](#component-versions) of the component.

When GitLab creates a new pipeline, the component's configuration is fetched and added to
the pipeline's configuration.

### Component versions

In order of highest priority first, the component version can be:

- A commit SHA, for example `e3262fdd0914fa823210cdb79a8c421e2cef79d8`.
- A tag, for example: `1.0`. If a tag and commit SHA exist with the same name,
  the commit SHA takes precedence over the tag.
- A branch name, for example `main`. If a branch and tag exist with the same name,
  the tag takes precedence over the branch.
- `~latest`, which is a special version that always points to the most recent
  [release published in the CI/CD Catalog](#publish-a-new-release).

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](https://gitlab.com/gitlab-org/gitlab/-/issues/427286) proposes to
change this behavior.

## CI/CD Catalog **(FREE ALL BETA)**

> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/407249) in GitLab 16.1 as an [experiment](../../policy/experiment-beta-support.md#experiment).
> - [Moved](https://gitlab.com/gitlab-org/gitlab/-/issues/432045) to [beta](../../policy/experiment-beta-support.md#beta) in GitLab 16.7.

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 [create a component project](#create-a-component-project) and add it 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**.
1. Select **Explore**.
1. Select **CI/CD Catalog**.

Alternatively, if you are already in the [pipeline editor](../pipeline_editor/index.md)
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.
1. 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.

Prerequisites:

- You must have the Owner role in the project.

To set the project as a catalog resource:

1. On the left sidebar, select **Search or go to** and find your project.
1. Select **Settings > General**.
1. Expand **Visibility, project features, permissions**.
1. Turn on the **CI/CD Catalog resource** toggle.

The project only becomes findable in the catalog after you publish a new release.

#### Publish a new release

CI/CD components can be [used](#use-a-component) without being listed in the CI/CD catalog.
However, publishing a component's releases in the catalog makes it discoverable to other users.

Prerequisites:

- The project must:
  - Be set as a [catalog resource](#set-a-component-project-as-a-catalog-resource).
  - Have a [project description](../../user/project/working_with_projects.md#edit-project-name-and-description) defined.
  - Have a `README.md` file in the root directory for the commit SHA of the tag being released.
  - Have at least one [CI/CD component in the `templates/` directory](#directory-structure)
    for the commit SHA of the tag being released.

To publish a new version of the component to the catalog:

1. Add a job to the project's `.gitlab-ci.yml` file that uses the [`release`](../yaml/index.md#release)
   keyword to create the new release. For example:

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

1. Create a [new tag](../../user/project/repository/tags/index.md#create-a-tag) for the release,
   which should trigger a tag pipeline that contains the job responsible for creating the release.
   You should configure the tag pipeline to [test the components](#test-the-component) before
   running the release job.

After the release job completes successfully, the release is created and the new version
is published to the CI/CD catalog.

### Unpublish a component project

To remove a component project from the catalog, turn off the [**CI/CD Catalog resource**](#set-a-component-project-as-a-catalog-resource)
toggle in the project settings.

WARNING:
This action destroys the metadata about the component project and its versions published
in the catalog. The project and its repository still exist, but are not visible in the catalog.

To publish the component project in the catalog again, you need to [publish a new release](#publish-a-new-release).

## Best practices

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

### Write a clear `README.md`

Each component project should have clear and comprehensive documentation. To
write a good `README.md` file:

- The documentation should start with a summary of the capabilities that the components in the project provide.
- If the project contains multiple components, use a [table of contents](../../user/markdown.md#table-of-contents)
   to help users quickly jump to a specific component's details.
- Add a `## Components` section with sub-sections like `### Component A` for each component in the project.
- In each component section:
  - Add a description of what the component does.
  - Add at least one YAML example showing how to use it.
  - If the component uses inputs, add a table showing all inputs with name, description, type, and default value.
  - If the component uses any variables or secrets, those should be documented too.
- A `## Contribute` section is recommended if contributions are welcome.

If a component needs more instructions, add additional documentation in a Markdown file
in the component directory and link to it from the main `README.md` file. For example:

```plaintext
README.md    # with links to the specific docs.md
templates/
├── component-1/
│   ├── template.yml
│   └── docs.md
└── component-2/
    ├── template.yml
    └── docs.md
```

For an example of a component `README.md`, see the [Deploy to AWS with GitLab CI/CD component's `README.md`](https://gitlab.com/components/aws/-/blob/main/README.md).

### 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](../../api/rest/index.md) if needed.

For example:

```yaml
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]

# Check if `component-job` is added.
# This example job could also test 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 the pipeline is for a new tag with a semantic version, and all previous jobs succeed,
# create the release.
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 creates
a release if the earlier jobs pass.

#### Test a component against sample files

In some cases, components require source files to interact with. For example, a component
that builds Go source code likely needs some samples of Go to test against. Alternatively,
a component that builds Docker images likely needs some sample Dockerfiles to test against.

You can include sample files like these directly in the component project, to be used
during component testing. For example, you can see the [code-quality CI/CD component's testing samples](https://gitlab.com/components/code-quality/-/tree/main/src).

### Avoid using global keywords

Avoid using [global keywords](../yaml/index.md#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:

- Add the configuration directly to each job, even if it creates some duplication
  in the component configuration.
- Use the [`extends`](../yaml/index.md#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, avoid using the `default` global keyword:

```yaml
# 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 explicitly:

  ```yaml
  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:

  ```yaml
  .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 hardcoded values with inputs

Avoid using hardcoded values in CI/CD components. Hardcoded 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 hardcoded, all pipelines using the component **must** either define
the exact same stage, or [override](../yaml/includes.md#override-included-configuration-values)
the configuration.

The preferred method is to use the [`input` keyword](../yaml/inputs.md) for dynamic
component configuration. The component user can specify the exact value they need.

For example, to create a component with `stage` configuration that can be defined by users:

- In the component configuration:

  ```yaml
  spec:
    inputs:
      stage:
        default: test
  ---
  unit-test:
    stage: $[[ inputs.stage ]]
    script: echo unit tests

  integration-test:
    stage: $[[ inputs.stage ]]
    script: echo integration tests
  ```

- In a project using the component:

  ```yaml
  stages: [verify, deploy]

  include:
    - component: gitlab.com/gitlab-org/ruby-test@1.0
      inputs:
        stage: verify
  ```

### 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 asking users to define custom variables to configure
components when `inputs` is a better solution.

Inputs are explicitly defined in the component's specs, and have better validation 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 configure a scanner's output format:

- In the component configuration:

  ```yaml
  spec:
    inputs:
      scanner-output:
        default: json
  ---
  my-scanner:
    script: my-scan --output $[[ inputs.scanner-output ]]
  ```

- In the project using the component:

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

In other cases, CI/CD variables might still be preferred. For example:

- Use [predefined variables](../variables/predefined_variables.md) to automatically configure
  a component to match a user's project.
- Ask users to store sensitive values as [masked or protected CI/CD variables in project settings](../variables/index.md#define-a-cicd-variable-in-the-ui).

### Use semantic versioning

When tagging and [releasing new versions](#publish-a-new-release) of components,
you should use [semantic versioning](https://semver.org). 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 grouped with other components as part of
   an existing [component project](index.md#component-project), or [create a new component project](#create-a-component-project).
1. Create a YAML file in the component project according to the [directory structure](index.md#directory-structure).
1. Copy the content of the original template YAML file into the new component YAML file.
1. Refactor the new component's configuration to:
   - Follow the [best practices](index.md#best-practices) for components.
   - Improve the configuration, for example by enabling [merge request pipelines](../pipelines/merge_request_pipelines.md)
     or making it [more efficient](../pipelines/pipeline_efficiency.md).
1. Leverage the `.gitlab-ci.yml` in the components repository to [test changes to the component](index.md#test-the-component).
1. Tag and [release the component](#publish-a-new-release).

## 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](#set-a-component-project-as-a-catalog-resource):

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

The `~latest` behavior [was updated](https://gitlab.com/gitlab-org/gitlab/-/issues/429707)
in GitLab 16.7. It now refers to the latest published version of the catalog resource. To resolve this issue, [create a new release](#publish-a-new-release).