gitlab-org--gitlab-foss/doc/ci/pipelines/multi_project_pipelines.md

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

Multi-project pipelines (FREE)

Moved to GitLab Free in 12.8.

You can set up GitLab CI/CD across multiple projects, so that a pipeline in one project can trigger a pipeline in another project. You can visualize the entire pipeline in one place, including all cross-project interdependencies.

For example, you might deploy your web application from three different projects in GitLab. Each project has its own build, test, and deploy process. With multi-project pipelines you can visualize the entire pipeline, including all build and test stages for all three projects.

For an overview, see the Multi-project pipelines demo.

Multi-project pipelines are also useful for larger products that require cross-project interdependencies, like those with a microservices architecture. Learn more in the Cross-project Pipeline Triggering and Visualization demo at GitLab@learn, in the Continuous Integration section.

If you trigger a pipeline in a downstream private project, on the upstream project's pipelines page, you can view:

• The name of the project.
• The status of the pipeline.

If you have a public project that can trigger downstream pipelines in a private project, make sure there are no confidentiality problems.

Create multi-project pipelines

To create multi-project pipelines, you can:

• Define them in your .gitlab-ci.yml file.
• Use the API.

Define multi-project pipelines in your .gitlab-ci.yml file

Moved to GitLab Free in 12.8.

When you create a multi-project pipeline in your .gitlab-ci.yml file, you create what is called a trigger job. For example:

rspec:
  stage: test
  script: bundle exec rspec

staging:
  variables:
    ENVIRONMENT: staging
  stage: deploy
  trigger: my/deployment

In this example, after the rspec job succeeds in the test stage, the staging trigger job starts. The initial status of this job is pending.

GitLab then creates a downstream pipeline in the my/deployment project and, as soon as the pipeline is created, the staging job succeeds. The full path to the project is my/deployment.

You can view the status for the pipeline, or you can display the downstream pipeline's status instead.

The user that creates the upstream pipeline must be able to create pipelines in the downstream project (my/deployment) too. If the downstream project is not found, or the user does not have permission to create a pipeline there, the staging job is marked as failed.

Trigger job configuration keywords

Trigger jobs can use only a limited set of the GitLab CI/CD configuration keywords. The keywords available for use in trigger jobs are:

• trigger
• stage
• allow_failure
• rules
• only and except
• when (only with a value of on_success, on_failure, or always)
• extends
• needs, but not needs:project

Specify a downstream pipeline branch

You can specify a branch name for the downstream pipeline to use. GitLab uses the commit on the head of the branch to create the downstream pipeline.

rspec:
  stage: test
  script: bundle exec rspec

staging:
  stage: deploy
  trigger:
    project: my/deployment
    branch: stable-11-2

Use:

• The project keyword to specify the full path to a downstream project.
• The branch keyword to specify the name of a branch in the project specified by project. In GitLab 12.4 and later, variable expansion is supported.

Pipelines triggered on a protected branch in a downstream project use the role of the user that ran the trigger job in the upstream project. If the user does not have permission to run CI/CD pipelines against the protected branch, the pipeline fails. See pipeline security for protected branches.

Pass CI/CD variables to a downstream pipeline by using the variables keyword

Sometimes you might want to pass CI/CD variables to a downstream pipeline. You can do that by using the variables keyword, just like you would for any other job.

rspec:
  stage: test
  script: bundle exec rspec

staging:
  variables:
    ENVIRONMENT: staging
  stage: deploy
  trigger: my/deployment

The ENVIRONMENT variable is passed to every job defined in a downstream pipeline. It is available as a variable when GitLab Runner picks a job.

In the following configuration, the MY_VARIABLE variable is passed to the downstream pipeline that is created when the trigger-downstream job is queued. This is because trigger-downstream job inherits variables declared in global variables blocks, and then we pass these variables to a downstream pipeline.

variables:
  MY_VARIABLE: my-value

trigger-downstream:
  variables:
    ENVIRONMENT: something
  trigger: my/project

You can stop global variables from reaching the downstream pipeline by using the inherit:variables keyword. In this example, the MY_GLOBAL_VAR variable is not available in the triggered pipeline:

variables:
  MY_GLOBAL_VAR: value

trigger-downstream:
  inherit:
    variables: false
  variables:
    MY_LOCAL_VAR: value
  trigger: my/project

You might want to pass some information about the upstream pipeline using, for example, predefined variables. In order to do that, you can use interpolation to pass any variable. For example:

downstream-job:
  variables:
    UPSTREAM_BRANCH: $CI_COMMIT_REF_NAME
  trigger: my/project

In this scenario, the UPSTREAM_BRANCH variable with a value related to the upstream pipeline is passed to the downstream-job job. It is available in the context of all downstream builds.

Upstream pipelines take precedence over downstream ones. If there are two variables with the same name defined in both upstream and downstream projects, the ones defined in the upstream project take precedence.

Pass CI/CD variables to a downstream pipeline by using variable inheritance

You can pass variables to a downstream pipeline with dotenv variable inheritance and needs:project.

In the upstream pipeline:

1. Save the variables in a .env file.

2. Save the .env file as a dotenv report.

3. Trigger the downstream pipeline.

   build_vars:
     stage: build
     script:
       - echo "BUILD_VERSION=hello" >> build.env
     artifacts:
       reports:
         dotenv: build.env
   
   deploy:
     stage: deploy
     trigger: my/downstream_project
   

4. Set the test job in the downstream pipeline to inherit the variables from the build_vars job in the upstream project with needs. The test job inherits the variables in the dotenv report and it can access BUILD_VERSION in the script:

   test:
     stage: test
     script:
       - echo $BUILD_VERSION
     needs:
       - project: my/upstream_project
         job: build_vars
         ref: master
         artifacts: true
   

Use rules or only/except with multi-project pipelines

You can use CI/CD variables or the rules keyword to control job behavior for multi-project pipelines. When a downstream pipeline is triggered with the trigger keyword, the value of the $CI_PIPELINE_SOURCE predefined variable is pipeline for all its jobs.

If you use only/except to control job behavior, use the pipelines keyword.

Mirror status of a triggered pipeline in the trigger job

• Introduced in GitLab Premium 12.3.
• Moved to GitLab Free in 12.8.

You can mirror the pipeline status from the triggered pipeline to the source trigger job by using strategy: depend. For example:

trigger_job:
  trigger:
    project: my/project
    strategy: depend

Create multi-project pipelines by using the API

Moved to GitLab Free in 12.4.

When you use the CI_JOB_TOKEN to trigger pipelines, GitLab recognizes the source of the job token. The pipelines become related, so you can visualize their relationships on pipeline graphs.

These relationships are displayed in the pipeline graph by showing inbound and outbound connections for upstream and downstream pipeline dependencies.

When using:

• CI/CD variables or rules to control job behavior, the value of the $CI_PIPELINE_SOURCE predefined variable is pipeline for multi-project pipeline triggered through the API with CI_JOB_TOKEN.
• only/except to control job behavior, use the pipelines keyword.

Trigger a pipeline when an upstream project is rebuilt (PREMIUM)

Introduced in GitLab 12.8.

You can trigger a pipeline in your project whenever a pipeline finishes for a new tag in a different project.

Prerequisites:

• The upstream project must be public.
• The user must have the Developer role in the upstream project.

To trigger the pipeline when the upstream project is rebuilt:

1. On the top bar, select Menu > Projects and find your project.
2. On the left sidebar, select Settings > CI/CD.
3. Expand Pipeline subscriptions.
4. Enter the project you want to subscribe to, in the format <namespace>/<project>. For example, if the project is https://gitlab.com/gitlab-org/gitlab, use gitlab-org/gitlab.
5. Select Subscribe.

Any pipelines that complete successfully for new tags in the subscribed project now trigger a pipeline on the current project's default branch. The maximum number of upstream pipeline subscriptions is 2 by default, for both the upstream and downstream projects. On self-managed instances, an administrator can change this limit.

Multi-project pipeline visualization (PREMIUM)

When you configure GitLab CI/CD for your project, you can visualize the stages of your jobs on a pipeline graph.

In the merge request, on the Pipelines tab, multi-project pipeline mini-graphs are displayed. They expand and are shown adjacent to each other when hovering (or tapping on touchscreen devices).