debian-mirror-gitlab/doc/ci/jobs/job_control.md
2021-06-08 01:23:25 +05:30

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Choose when to run jobs (FREE)

When a new pipeline starts, GitLab checks the pipeline configuration to determine which jobs should run in that pipeline. You can configure jobs to run depending on the status of variables, the pipeline type, and so on.

To configure a job to be included or excluded from certain pipelines, you can use:

Use needs to configure a job to run as soon as the earlier jobs it depends on finish running.

Specify when jobs run with only and except

You can use only and except to control when to add jobs to pipelines.

  • Use only to define when a job runs.
  • Use except to define when a job does not run.

only:refs / except:refs examples

only or except used without refs is the same as only:refs / except/refs

In the following example, job runs only for:

job:
  # use special keywords
  only:
    - tags
    - triggers
    - schedules

To execute jobs only for the parent repository and not forks:

job:
  only:
    - branches@gitlab-org/gitlab
  except:
    - main@gitlab-org/gitlab
    - /^release/.*$/@gitlab-org/gitlab

This example runs job for all branches on gitlab-org/gitlab, except main and branches that start with release/.

only: variables / except: variables examples

You can use except:variables to exclude jobs based on a commit message:

end-to-end:
  script: rake test:end-to-end
  except:
    variables:
      - $CI_COMMIT_MESSAGE =~ /skip-end-to-end-tests/

You can use parentheses with && and || to build more complicated variable expressions:

job1:
  script:
    - echo This rule uses parentheses.
  only:
    variables:
      - ($CI_COMMIT_BRANCH == "master" || $CI_COMMIT_BRANCH == "develop") && $MY_VARIABLE

only:changes / except:changes examples

You can skip a job if a change is detected in any file with a .md extension in the root directory of the repository:

build:
  script: npm run build
  except:
    changes:
      - "*.md"

If you change multiple files, but only one file ends in .md, the build job is still skipped. The job does not run for any of the files.

Read more about how to use only:changes and except:changes:

Use only:changes with pipelines for merge requests

With pipelines for merge requests, it's possible to define a job to be created based on files modified in a merge request.

Use this keyword with only: [merge_requests] so GitLab can find the correct base SHA of the source branch. File differences are correctly calculated from any further commits, and all changes in the merge requests are properly tested in pipelines.

For example:

docker build service one:
  script: docker build -t my-service-one-image:$CI_COMMIT_REF_SLUG .
  only:
    refs:
      - merge_requests
    changes:
      - Dockerfile
      - service-one/**/*

In this scenario, if a merge request changes files in the service-one directory or the Dockerfile, GitLab creates the docker build service one job.

For example:

docker build service one:
  script: docker build -t my-service-one-image:$CI_COMMIT_REF_SLUG .
  only:
    changes:
      - Dockerfile
      - service-one/**/*

In this example, the pipeline might fail because of changes to a file in service-one/**/*.

A later commit that doesn't have changes in service-one/**/* but does have changes to the Dockerfile can pass. The job only tests the changes to the Dockerfile.

GitLab checks the most recent pipeline that passed. If the merge request is mergeable, it doesn't matter that an earlier pipeline failed because of a change that has not been corrected.

When you use this configuration, ensure that the most recent pipeline properly corrects any failures from previous pipelines.

Use only:changes without pipelines for merge requests

Without pipelines for merge requests, pipelines run on branches or tags that don't have an explicit association with a merge request. In this case, a previous SHA is used to calculate the diff, which is equivalent to git diff HEAD~. This can result in some unexpected behavior, including:

  • When pushing a new branch or a new tag to GitLab, the policy always evaluates to true.
  • When pushing a new commit, the changed files are calculated by using the previous commit as the base SHA.

Use only:changes with scheduled pipelines

only:changes always evaluates as true in Scheduled pipelines. All files are considered to have changed when a scheduled pipeline runs.

Combine multiple keywords with only or except

If you use multiple keywords with only or except, the keywords are evaluated as a single conjoined expression. That is:

  • only: includes the job if all of the keys have at least one condition that matches.
  • except: excludes the job if any of the keys have at least one condition that matches.

With only, individual keys are logically joined by an AND. A job is added to the pipeline if the following is true:

  • (any listed refs are true) AND (any listed variables are true) AND (any listed changes are true) AND (any chosen Kubernetes status matches)

In the following example, the test job is only created when all of the following are true:

  • The pipeline is scheduled or runs for main.
  • The variables keyword matches.
  • The kubernetes service is active on the project.
test:
  script: npm run test
  only:
    refs:
      - main
      - schedules
    variables:
      - $CI_COMMIT_MESSAGE =~ /run-end-to-end-tests/
    kubernetes: active

With except, individual keys are logically joined by an OR. A job is not added if the following is true:

  • (any listed refs are true) OR (any listed variables are true) OR (any listed changes are true) OR (a chosen Kubernetes status matches)

In the following example, the test job is not created when any of the following are true:

  • The pipeline runs for the main branch.
  • There are changes to the README.md file in the root directory of the repository.
test:
  script: npm run test
  except:
    refs:
      - main
    changes:
      - "README.md"

Use predefined CI/CD variables to run jobs only in specific pipeline types

You can use predefined CI/CD variables to choose which pipeline types jobs run in, with:

The following table lists some of the variables that you can use, and the pipeline types the variables can control for:

  • Branch pipelines that run for Git push events to a branch, like new commits or tags.
  • Tag pipelines that run only when a new Git tag is pushed to a branch.
  • Merge request pipelines that run for changes to a merge request, like new commits or selecting the Run pipeline button in a merge request's pipelines tab.
  • Scheduled pipelines.
Variables Branch Tag Merge request Scheduled
CI_COMMIT_BRANCH Yes Yes
CI_COMMIT_TAG Yes Yes, if the scheduled pipeline is configured to run on a tag.
CI_PIPELINE_SOURCE = push Yes Yes
CI_PIPELINE_SOURCE = scheduled Yes
CI_PIPELINE_SOURCE = merge_request_event Yes
CI_MERGE_REQUEST_IID Yes

For example, to configure a job to run for merge request pipelines and scheduled pipelines, but not branch or tag pipelines:

job1:
  script:
    - echo
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
    - if: $CI_PIPELINE_SOURCE == "scheduled"
    - if: $CI_PIPELINE_SOURCE == "push"
      when: never

Regular expressions

The @ symbol denotes the beginning of a ref's repository path. To match a ref name that contains the @ character in a regular expression, you must use the hex character code match \x40.

Only the tag or branch name can be matched by a regular expression. The repository path, if given, is always matched literally.

To match the tag or branch name, the entire ref name part of the pattern must be a regular expression surrounded by /. For example, you can't use issue-/.*/ to match all tag names or branch names that begin with issue-, but you can use /issue-.*/.

Regular expression flags must be appended after the closing /. Pattern matching is case-sensitive by default. Use the i flag modifier, like /pattern/i, to make a pattern case-insensitive:

job:
  # use regexp
  only:
    - /^issue-.*$/i
  # use special keyword
  except:
    - branches

Use anchors ^ and $ to avoid the regular expression matching only a substring of the tag name or branch name. For example, /^issue-.*$/ is equivalent to /^issue-/, while just /issue/ would also match a branch called severe-issues.

only / except regex syntax

In GitLab 11.9.4, GitLab began internally converting the regexp used in only and except keywords to RE2.

RE2 limits the set of available features due to computational complexity, and some features, like negative lookaheads, became unavailable. Only a subset of features provided by Ruby Regexp are now supported.

From GitLab 11.9.7 to GitLab 12.0, GitLab provided a feature flag to let you use unsafe regexp syntax. After migrating to safe syntax, you should disable this feature flag again:

Feature.enable(:allow_unsafe_ruby_regexp)