summaryrefslogtreecommitdiff
path: root/doc/ci/triggers/README.md
blob: 2b006b8779b097e31198e16d34a15e42abb0e9ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
---
stage: Verify
group: Continuous Integration
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
type: tutorial
---

# Triggering pipelines through the API

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](#trigger-token)
- [CI job token](#ci-job-token)

If using the `$CI_PIPELINE_SOURCE` [predefined environment variable](../variables/predefined_variables.md)
to limit which jobs run in a pipeline, the value could be either `pipeline` or `trigger`,
depending on which trigger method is used.

| `$CI_PIPELINE_SOURCE` value | Trigger method |
|-----------------------------|----------------|
| `pipeline`                  | Using the `trigger:` keyword in the CI/CD configuration file, or using the trigger API with `$CI_JOB_TOKEN`. |
| `trigger`                   | Using the trigger API using a generated trigger token |

This also applies when using the `pipelines` or `triggers` keywords with the legacy [`only/except` basic syntax](../yaml/README.md#onlyexcept-basic).

### Trigger token

A unique trigger token can be obtained when [adding a new trigger](#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](../variables/README.md#gitlab-cicd-environment-variables)
to protect trigger tokens.

### CI job token

You can use the `CI_JOB_TOKEN` [variable](../variables/README.md#predefined-environment-variables) (used to authenticate
with the [GitLab Container Registry](../../user/packages/container_registry/index.md)) in the following cases.

#### When used with multi-project pipelines

> - Use of `CI_JOB_TOKEN` for multi-project pipelines was [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/2017) in [GitLab Premium](https://about.gitlab.com/pricing/) 9.3.
> - Use of `CI_JOB_TOKEN` for multi-project pipelines was [made available](https://gitlab.com/gitlab-org/gitlab/-/issues/31573) in all tiers in GitLab 12.4.

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](../multi_project_pipelines.md#overview). For example:

```yaml
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](../../api/pipeline_triggers.md).

#### When a pipeline depends on the artifacts of another pipeline **(PREMIUM)**

> The use of `CI_JOB_TOKEN` in the artifacts download API was [introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/2346) in [GitLab Premium](https://about.gitlab.com/pricing/) 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:

```yaml
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](../../user/permissions.md#job-permissions).

Read more about the [jobs API](../../api/job_artifacts.md#download-the-artifacts-archive).

## 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.

![Triggers page overview](img/triggers_page.png)

## 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

To trigger a job you need to send a `POST` request to GitLab's API endpoint:

```plaintext
POST /projects/:id/trigger/pipeline
```

The required parameters are the [trigger's `token`](#authentication-tokens)
and the Git `ref` on which the trigger will be performed. Valid refs are
branches or tags. The `:id` of a project can be found by
[querying the API](../../api/projects.md) 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'.

![Marked rebuilds as on jobs page](img/builds_page.png)

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.

![Marked rebuilds as triggered on a single job page](img/trigger_single_build.png)

By using cURL you can trigger a pipeline rerun with minimal effort, for example:

```shell
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:

```shell
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 A's `.gitlab-ci.yml`:

```yaml
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
```

This means that 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

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):

```plaintext
https://gitlab.example.com/api/v4/projects/9/ref/master/trigger/pipeline?token=TOKEN
```

`ref` should be passed as part of the URL in order to take precedence over
`ref` 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.

## 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/CD so that they can be used in your `.gitlab-ci.yml`
file. The parameter is of the form:

```plaintext
variables[key]=value
```

This information is also exposed in the UI. Please note that _values_ are only viewable by Owners and Maintainers.

![Job variables in UI](img/trigger_variables.png)

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](../yaml/README.md#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.

```yaml
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:

```shell
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
```

Trigger variables have the [highest priority](../variables/README.md#priority-of-environment-variables)
of all types of variables.

## Using cron to trigger nightly pipelines

NOTE: **Note:**
The following behavior can also be achieved through GitLab's UI with
[pipeline schedules](../pipelines/schedules.md).

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`:

```shell
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.