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Triggering pipelines through the API
Notes:
- Introduced in GitLab 7.14.
- GitLab 8.12 has a completely redesigned job permissions system. Read all about the new model and its implications.
Triggers can be used to force a pipeline rerun of a specific ref
(branch or
tag) with an API call.
Authentication tokens
The following methods of authentication are supported.
Trigger token
A unique trigger token can be obtained when adding a new trigger.
DANGER: Danger:
Passing plain text tokens in public projects is a security issue. Potential
attackers can impersonate the user that exposed their trigger token publicly in
their .gitlab-ci.yml
file. Use variables
to protect trigger tokens.
CI job token
You can use the CI_JOB_TOKEN
variable (used to authenticate
with the GitLab Container Registry) in the following cases.
When used with multi-project pipelines [PREMIUM]
Note
The use of
CI_JOB_TOKEN
for multi-project pipelines was introduced in GitLab Premium 9.3.
This way of triggering can only be used when invoked inside .gitlab-ci.yml
,
and it creates a dependent pipeline relation visible on the
pipeline graph. For example:
build_docs:
stage: deploy
script:
- curl --request POST --form "token=$CI_JOB_TOKEN" --form ref=master https://gitlab.example.com/api/v4/projects/9/trigger/pipeline
only:
- tags
Pipelines triggered that way also expose a special variable:
CI_PIPELINE_SOURCE=pipeline
.
Read more about the pipelines trigger API.
When a pipeline depends on the artifacts of another pipeline [PREMIUM]
The use of
CI_JOB_TOKEN
in the artifacts download API was introduced in GitLab Premium 9.5.
With the introduction of dependencies between different projects, one of
them may need to access artifacts created by a previous one. This process
must be granted for authorized accesses, and it can be done using the
CI_JOB_TOKEN
variable that identifies a specific job. For example:
build_submodule:
image: debian
stage: test
script:
- apt update && apt install -y unzip
- curl --location --output artifacts.zip "https://gitlab.example.com/api/v4/projects/1/jobs/artifacts/master/download?job=test&job_token=$CI_JOB_TOKEN"
- unzip artifacts.zip
only:
- tags
This allows you to use that for multi-project pipelines and download artifacts from any project to which you have access as this follows the same principles with the permission model.
Read more about the jobs API.
Adding a new trigger
You can add a new trigger by going to your project's Settings ➔ CI/CD under Triggers. The Add trigger button will create a new token which you can then use to trigger a rerun of this particular project's pipeline.
Every new trigger you create, gets assigned a different token which you can
then use inside your scripts or .gitlab-ci.yml
. You also have a nice
overview of the time the triggers were last used.
Revoking a trigger
You can revoke a trigger any time by going at your project's Settings ➔ CI/CD under Triggers and hitting the Revoke button. The action is irreversible.
Triggering a pipeline
Notes:
- Valid refs are only the branches and tags. If you pass a commit SHA as a ref, it will not trigger a job.
To trigger a job you need to send a POST
request to GitLab's API endpoint:
POST /projects/:id/trigger/pipeline
The required parameters are the trigger's token
and the Git ref
on which the trigger will be performed. Valid refs are the
branch and the tag. The :id
of a project can be found by
querying the API or by visiting the CI/CD
settings page which provides self-explanatory examples.
When a rerun of a pipeline is triggered, the information is exposed in GitLab's UI under the Jobs page and the jobs are marked as triggered 'by API'.
You can see which trigger caused the rebuild by visiting the single job page. A part of the trigger's token is exposed in the UI as you can see from the image below.
By using cURL you can trigger a pipeline rerun with minimal effort, for example:
curl --request POST \
--form token=TOKEN \
--form ref=master \
https://gitlab.example.com/api/v4/projects/9/trigger/pipeline
In this case, the project with ID 9
will get rebuilt on master
branch.
Alternatively, you can pass the token
and ref
arguments in the query string:
curl --request POST \
"https://gitlab.example.com/api/v4/projects/9/trigger/pipeline?token=TOKEN&ref=master"
You can also benefit by using triggers in your .gitlab-ci.yml
. Let's say that
you have two projects, A and B, and you want to trigger a rebuild on the master
branch of project B whenever a tag on project A is created. This is the job you
need to add in project's A .gitlab-ci.yml
:
build_docs:
stage: deploy
script:
- "curl --request POST --form token=TOKEN --form ref=master https://gitlab.example.com/api/v4/projects/9/trigger/pipeline"
only:
- tags
Now, whenever a new tag is pushed on project A, the job will run and the
build_docs
job will be executed, triggering a rebuild of project B. The
stage: deploy
ensures that this job will run only after all jobs with
stage: test
complete successfully.
Triggering a pipeline from a webhook
Notes:
- Introduced in GitLab 8.14.
ref
should be passed as part of the URL in order to take precedence overref
from the webhook body that designates the branch ref that fired the trigger in the source repository.ref
should be URL-encoded if it contains slashes.
To trigger a job from a webhook of another project you need to add the following webhook URL for Push and Tag events (change the project ID, ref and token):
https://gitlab.example.com/api/v4/projects/9/ref/master/trigger/pipeline?token=TOKEN
Making use of trigger variables
You can pass any number of arbitrary variables in the trigger API call and they
will be available in GitLab CI so that they can be used in your .gitlab-ci.yml
file. The parameter is of the form:
variables[key]=value
This information is also exposed in the UI. Please note that values are only viewable by Owners and Maintainers.
Using trigger variables can be proven useful for a variety of reasons:
- Identifiable jobs. Since the variable is exposed in the UI you can know why the rebuild was triggered if you pass a variable that explains the purpose.
- Conditional job processing. You can have conditional jobs that run whenever a certain variable is present.
Consider the following .gitlab-ci.yml
where we set three
stages and the upload_package
job is run only
when all jobs from the test and build stages pass. When the UPLOAD_TO_S3
variable is non-zero, make upload
is run.
stages:
- test
- build
- package
run_tests:
stage: test
script:
- make test
build_package:
stage: build
script:
- make build
upload_package:
stage: package
script:
- if [ -n "${UPLOAD_TO_S3}" ]; then make upload; fi
You can then trigger a rebuild while you pass the UPLOAD_TO_S3
variable
and the script of the upload_package
job will run:
curl --request POST \
--form token=TOKEN \
--form ref=master \
--form "variables[UPLOAD_TO_S3]=true" \
https://gitlab.example.com/api/v4/projects/9/trigger/pipeline
Using cron to trigger nightly pipelines
Note: The following behavior can also be achieved through GitLab's UI with pipeline schedules.
Whether you craft a script or just run cURL directly, you can trigger jobs
in conjunction with cron. The example below triggers a job on the master
branch of project with ID 9
every night at 00:30
:
30 0 * * * curl --request POST --form token=TOKEN --form ref=master https://gitlab.example.com/api/v4/projects/9/trigger/pipeline
Legacy triggers
Old triggers, created before GitLab 9.0 will be marked as legacy.
Triggers with the legacy label do not have an associated user and only have access to the current project. They are considered deprecated and will be removed with one of the future versions of GitLab.