Choose when to run jobs

DETAILS: Tier: Free, Premium, Ultimate Offering: SaaS, self-managed

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 factors like the status of variables, or the pipeline type.

To configure a job to be included or excluded from certain pipelines, use rules.

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

Specify when jobs run with rules

• Introduced in GitLab 12.3.

Use rules to include or exclude jobs in pipelines.

Rules are evaluated in order until the first match. When a match is found, the job is either included or excluded from the pipeline, depending on the configuration. See the rules reference for more details.

Future keyword improvements are being discussed in our epic for improving rules, where anyone can add suggestions or requests.

rules examples

The following example uses if to define that the job runs in only two specific cases:

job:
  script: echo "Hello, Rules!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      when: manual
      allow_failure: true
    - if: $CI_PIPELINE_SOURCE == "schedule"

• If the pipeline is for a merge request, the first rule matches, and the job is added to the merge request pipeline with attributes of:
  • when: manual (manual job)
  • allow_failure: true (the pipeline continues running even if the manual job is not run)
• If the pipeline is not for a merge request, the first rule doesn't match, and the second rule is evaluated.
• If the pipeline is a scheduled pipeline, the second rule matches, and the job is added to the scheduled pipeline. No attributes were defined, so it is added with:
  • when: on_success (default)
  • allow_failure: false (default)
• In all other cases, no rules match, so the job is not added to any other pipeline.

Alternatively, you can define a set of rules to exclude jobs in a few cases, but run them in all other cases:

job:
  script: echo "Hello, Rules!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      when: never
    - if: $CI_PIPELINE_SOURCE == "schedule"
      when: never
    - when: on_success

• If the pipeline is for a merge request, the job is not added to the pipeline.
• If the pipeline is a scheduled pipeline, the job is not added to the pipeline.
• In all other cases, the job is added to the pipeline, with when: on_success.

WARNING: If you use a when clause as the final rule (not including when: never), two simultaneous pipelines may start. Both push pipelines and merge request pipelines can be triggered by the same event (a push to the source branch for an open merge request). See how to prevent duplicate pipelines for more details.

Run jobs for scheduled pipelines

To configure a job to be executed only when the pipeline has been scheduled, use the rules keyword.

In this example, make world runs in scheduled pipelines, and make build runs in branch and tag pipelines:

job:on-schedule:
  rules:
    - if: $CI_PIPELINE_SOURCE == "schedule"
  script:
    - make world

job:
  rules:
    - if: $CI_PIPELINE_SOURCE == "push"
  script:
    - make build

Skip job if the branch is empty

Use rules:changes:compare_to to avoid running a job when the branch is empty, which saves CI/CD resources. Compare the branch to the default branch, and if the branch:

• Doesn't have changed files, the job doesn't run.
• Has changed files, the job runs.

For example, in a project with main as the default branch:

job:
  script:
    - echo "This job only runs for branches that are not empty"
  rules:
    - if: $CI_COMMIT_BRANCH
      changes:
        compare_to: 'refs/heads/main'
        paths:
          - '*'

The rule for this job compares all files and paths (*) in the current branch against the default branch main. The rule matches and the job runs only when there are changes to the files in the branch.

Complex rules

You can use all rules keywords, like if, changes, and exists, in the same rule. The rule evaluates to true only when all included keywords evaluate to true.

For example:

docker build:
  script: docker build -t my-image:$CI_COMMIT_REF_SLUG .
  rules:
    - if: $VAR == "string value"
      changes:  # Include the job and set to when:manual if any of the follow paths match a modified file.
        - Dockerfile
        - docker/scripts/*
      when: manual
      allow_failure: true

If the Dockerfile file or any file in /docker/scripts has changed and $VAR == "string value", then the job runs manually and is allowed to fail.

You can use parentheses with && and || to build more complicated variable expressions. Introduced in GitLab 13.3:

job1:
  script:
    - echo This rule uses parentheses.
  rules:
    - if: ($CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH || $CI_COMMIT_BRANCH == "develop") && $MY_VARIABLE

WARNING: Before GitLab 13.3, rules that use both || and && may evaluate with an unexpected order of operations.

Avoid duplicate pipelines

If a job uses rules, a single action, like pushing a commit to a branch, can trigger multiple pipelines. You don't have to explicitly configure rules for multiple types of pipeline to trigger them accidentally.

Some configurations that have the potential to cause duplicate pipelines cause a pipeline warning to be displayed.

For example:

job:
  script: echo "This job creates double pipelines!"
  rules:
    - if: $CUSTOM_VARIABLE == "false"
      when: never
    - when: always

This job does not run when $CUSTOM_VARIABLE is false, but it does run in all other pipelines, including both push (branch) and merge request pipelines. With this configuration, every push to an open merge request's source branch causes duplicated pipelines.

To avoid duplicate pipelines, you can:

• Use workflow to specify which types of pipelines can run.

• Rewrite the rules to run the job only in very specific cases, and avoid a final when rule:

  job:
    script: echo "This job does NOT create double pipelines!"
    rules:
      - if: $CUSTOM_VARIABLE == "true" && $CI_PIPELINE_SOURCE == "merge_request_event"

You can also avoid duplicate pipelines by changing the job rules to avoid either push (branch) pipelines or merge request pipelines. However, if you use a - when: always rule without workflow: rules, GitLab still displays a pipeline warning.

For example, the following does not trigger double pipelines, but is not recommended without workflow: rules:

job:
  script: echo "This job does NOT create double pipelines!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "push"
      when: never
    - when: always

You should not include both push and merge request pipelines in the same job without workflow:rules that prevent duplicate pipelines:

job:
  script: echo "This job creates double pipelines!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "push"
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"

Also, do not mix only/except jobs with rules jobs in the same pipeline. It may not cause YAML errors, but the different default behaviors of only/except and rules can cause issues that are difficult to troubleshoot:

job-with-no-rules:
  script: echo "This job runs in branch pipelines."

job-with-rules:
  script: echo "This job runs in merge request pipelines."
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"

For every change pushed to the branch, duplicate pipelines run. One branch pipeline runs a single job (job-with-no-rules), and one merge request pipeline runs the other job (job-with-rules). Jobs with no rules default to except: merge_requests, so job-with-no-rules runs in all cases except merge requests.

Common if clauses for rules

For behavior similar to the only/except keywords, you can check the value of the $CI_PIPELINE_SOURCE variable:

The following example runs the job as a manual job in scheduled pipelines or in push pipelines (to branches or tags), with when: on_success (default). It does not add the job to any other pipeline type.

job:
  script: echo "Hello, Rules!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "schedule"
      when: manual
      allow_failure: true
    - if: $CI_PIPELINE_SOURCE == "push"

The following example runs the job as a when: on_success job in merge request pipelines and scheduled pipelines. It does not run in any other pipeline type.

job:
  script: echo "Hello, Rules!"
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
    - if: $CI_PIPELINE_SOURCE == "schedule"

Other commonly used variables for if clauses:

• if: $CI_COMMIT_TAG: If changes are pushed for a tag.
• if: $CI_COMMIT_BRANCH: If changes are pushed to any branch.
• if: $CI_COMMIT_BRANCH == "main": If changes are pushed to main.
• if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH: If changes are pushed to the default branch. Use when you want to have the same configuration in multiple projects with different default branches.
• if: $CI_COMMIT_BRANCH =~ /regex-expression/: If the commit branch matches a regular expression.
• if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH && $CI_COMMIT_TITLE =~ /Merge branch.*/: If the commit branch is the default branch and the commit message title matches a regular expression. For example, the default commit message for a merge commit starts with Merge branch.
• if: $CUSTOM_VARIABLE !~ /regex-expression/: If the custom variable CUSTOM_VARIABLE does not match a regular expression.
• if: $CUSTOM_VARIABLE == "value1": If the custom variable CUSTOM_VARIABLE is exactly value1.

Variables in rules:changes

• Introduced in GitLab 13.6.
• Feature flag removed in GitLab 13.7.

You can use CI/CD variables in rules:changes expressions to determine when to add jobs to a pipeline:

docker build:
  variables:
    DOCKERFILES_DIR: 'path/to/files'
  script: docker build -t my-image:$CI_COMMIT_REF_SLUG .
  rules:
    - changes:
        - $DOCKERFILES_DIR/*

You can use the $ character for both variables and paths. For example, if the $DOCKERFILES_DIR variable exists, its value is used. If it does not exist, the $ is interpreted as being part of a path.

Reuse rules in different jobs

• Introduced in GitLab 14.3.

Use !reference tags to reuse rules in different jobs. You can combine !reference rules with regular job-defined rules:

.default_rules:
  rules:
    - if: $CI_PIPELINE_SOURCE == "schedule"
      when: never
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH

job1:
  rules:
    - !reference [.default_rules, rules]
  script:
    - echo "This job runs for the default branch, but not schedules."

job2:
  rules:
    - !reference [.default_rules, rules]
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
  script:
    - echo "This job runs for the default branch, but not schedules."
    - echo "It also runs for merge requests."

Specify when jobs run with only and except

NOTE: only and except are not being actively developed. rules is the preferred keyword to control when to add jobs to pipelines.

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

You can use only or except with:

• Specific keywords. See the full list in the only/except syntax reference.
• Branch names. Avoid branch names that are exactly the same as a specific keyword. For example, jobs configured to run for the tags keyword (tag pipelines) would also run for a branch named tags.
• Regex patterns to specify a range of branch names.

The following examples omit refs because only or except used without refs is the same as only:refs / except/refs.

For example:

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

In this example, job runs only for:

• Git tags
• Triggers
• Scheduled pipelines

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 == "main" || $CI_COMMIT_BRANCH == "develop") && $MY_VARIABLE

When multiple entries are specified in only:variables, the job runs when at least one of them evaluates to true. You can use && in a single entry when multiple conditions must be satisfied at the same time.

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.

With some configurations that use changes, jobs or pipelines might run unexpectedly

Use only:changes with merge request pipelines

With merge request pipelines, 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.

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"

Create a job that must be run manually

You can require that a job doesn't run unless a user starts it. This is called a manual job. You might want to use a manual job for something like deploying to production.

To specify a job as manual, add when: manual to the job in the .gitlab-ci.yml file.

By default, manual jobs display as skipped when the pipeline starts.

You can use protected branches to more strictly protect manual deployments from being run by unauthorized users.

Types of manual jobs

Manual jobs can be either optional or blocking.

In optional manual jobs:

• allow_failure is true, which is the default setting for jobs that have when: manual and no rules, or when: manual defined outside of rules.
• The status does not contribute to the overall pipeline status. A pipeline can succeed even if all of its manual jobs fail.

In blocking manual jobs:

• allow_failure is false, which is the default setting for jobs that have when: manual defined inside rules.
• The pipeline stops at the stage where the job is defined. To let the pipeline continue running, run the manual job.
• Merge requests in projects with Pipelines must succeed enabled can't be merged with a blocked pipeline.
• The pipeline shows a status of blocked.

When using manual jobs in triggered pipelines with strategy: depend, the type of manual job can affect the trigger job's status while the pipeline runs.

Run a manual job

To run a manual job, you must have permission to merge to the assigned branch:

1. Go to the pipeline, job, environment, or deployment view.
2. Next to the manual job, select Play ({play}).

You can also add custom CI/CD variables when running a manual job.

Protect manual jobs

DETAILS: Tier: Premium, Ultimate Offering: SaaS, self-managed

Use protected environments to define a list of users authorized to run a manual job. You can authorize only the users associated with a protected environment to trigger manual jobs, which can:

• More precisely limit who can deploy to an environment.
• Block a pipeline until an approved user "approves" it.

To protect a manual job:

1. Add an environment to the job. For example:

   deploy_prod:
     stage: deploy
     script:
       - echo "Deploy to production server"
     environment:
       name: production
       url: https://example.com
     when: manual
     rules:
       - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH

2. In the protected environments settings, select the environment (production in this example) and add the users, roles or groups that are authorized to trigger the manual job to the Allowed to Deploy list. Only those in this list can trigger this manual job, as well as GitLab administrators who are always able to use protected environments.

You can use protected environments with blocking manual jobs to have a list of users allowed to approve later pipeline stages. Add allow_failure: false to the protected manual job and the pipeline's next stages only run after the manual job is triggered by authorized users.

Run a job after a delay

• Introduced in GitLab 11.4.

Use when: delayed to execute scripts after a waiting period, or if you want to avoid jobs immediately entering the pending state.

You can set the period with start_in keyword. The value of start_in is an elapsed time in seconds, unless a unit is provided. The minimum is one second, and the maximum is one week. Examples of valid values include:

• '5' (a value with no unit must be surrounded by single quotes)
• 5 seconds
• 30 minutes
• 1 day
• 1 week

When a stage includes a delayed job, the pipeline doesn't progress until the delayed job finishes. You can use this keyword to insert delays between different stages.

The timer of a delayed job starts immediately after the previous stage completes. Similar to other types of jobs, a delayed job's timer doesn't start unless the previous stage passes.

The following example creates a job named timed rollout 10% that is executed 30 minutes after the previous stage completes:

timed rollout 10%:
  stage: deploy
  script: echo 'Rolling out 10% ...'
  when: delayed
  start_in: 30 minutes
  environment: production

To stop the active timer of a delayed job, select Unschedule ({time-out}). This job can no longer be scheduled to run automatically. You can, however, execute the job manually.

To start a delayed job manually, select Unschedule ({time-out}) to stop the delay timer and then select Play ({play}). Soon GitLab Runner starts the job.

Parallelize large jobs

To split a large job into multiple smaller jobs that run in parallel, use the parallel keyword in your .gitlab-ci.yml file.

Different languages and test suites have different methods to enable parallelization. For example, use Semaphore Test Boosters and RSpec to run Ruby tests in parallel:

# Gemfile
source 'https://rubygems.org'

gem 'rspec'
gem 'semaphore_test_boosters'

test:
  parallel: 3
  script:
    - bundle
    - bundle exec rspec_booster --job $CI_NODE_INDEX/$CI_NODE_TOTAL

You can then navigate to the Jobs tab of a new pipeline build and see your RSpec job split into three separate jobs.

WARNING: Test Boosters reports usage statistics to the author.

Run a one-dimensional matrix of parallel jobs

• Introduced in GitLab 13.5.

You can create a one-dimensional matrix of parallel jobs:

deploystacks:
  stage: deploy
  script:
    - bin/deploy
  parallel:
    matrix:
      - PROVIDER: [aws, ovh, gcp, vultr]
  environment: production/$PROVIDER

You can also create a multi-dimensional matrix.

Run a matrix of parallel trigger jobs

• Introduced in GitLab 13.10.

You can run a trigger job multiple times in parallel in a single pipeline, but with different variable values for each instance of the job.

deploystacks:
  stage: deploy
  trigger:
    include: path/to/child-pipeline.yml
  parallel:
    matrix:
      - PROVIDER: aws
        STACK: [monitoring, app1]
      - PROVIDER: ovh
        STACK: [monitoring, backup]
      - PROVIDER: [gcp, vultr]
        STACK: [data]

This example generates 6 parallel deploystacks trigger jobs, each with different values for PROVIDER and STACK, and they create 6 different child pipelines with those variables.

deploystacks: [aws, monitoring]
deploystacks: [aws, app1]
deploystacks: [ovh, monitoring]
deploystacks: [ovh, backup]
deploystacks: [gcp, data]
deploystacks: [vultr, data]

Select different runner tags for each parallel matrix job

• Introduced in GitLab 14.1.

You can use variables defined in parallel: matrix with the tags keyword for dynamic runner selection:

deploystacks:
  stage: deploy
  parallel:
    matrix:
      - PROVIDER: aws
        STACK: [monitoring, app1]
      - PROVIDER: gcp
        STACK: [data]
  tags:
    - ${PROVIDER}-${STACK}
  environment: $PROVIDER/$STACK

Fetch artifacts from a parallel:matrix job

You can fetch artifacts from a job created with parallel:matrix by using the dependencies keyword. Use the job name as the value for dependencies as a string in the form:

<job_name> [<matrix argument 1>, <matrix argument 2>, ... <matrix argument N>]

For example, to fetch the artifacts from the job with a RUBY_VERSION of 2.7 and a PROVIDER of aws:

ruby:
  image: ruby:${RUBY_VERSION}
  parallel:
    matrix:
      - RUBY_VERSION: ["2.5", "2.6", "2.7", "3.0", "3.1"]
        PROVIDER: [aws, gcp]
  script: bundle install

deploy:
  image: ruby:2.7
  stage: deploy
  dependencies:
    - "ruby: [2.7, aws]"
  script: echo hello
  environment: production

Quotes around the dependencies entry are required.

Specify a parallelized job using needs with multiple parallelized jobs

• Introduced in GitLab 16.3.

You can use variables defined in needs:parallel:matrix with multiple parallelized jobs.

For example:

linux:build:
  stage: build
  script: echo "Building linux..."
  parallel:
    matrix:
      - PROVIDER: aws
        STACK:
          - monitoring
          - app1
          - app2

mac:build:
  stage: build
  script: echo "Building mac..."
  parallel:
    matrix:
      - PROVIDER: [gcp, vultr]
        STACK: [data, processing]

linux:rspec:
  stage: test
  needs:
    - job: linux:build
      parallel:
        matrix:
          - PROVIDER: aws
            STACK: app1
  script: echo "Running rspec on linux..."

mac:rspec:
  stage: test
  needs:
    - job: mac:build
      parallel:
        matrix:
          - PROVIDER: [gcp, vultr]
            STACK: [data]
  script: echo "Running rspec on mac..."

production:
  stage: deploy
  script: echo "Running production..."
  environment: production

This example generates several jobs. The parallel jobs each have different values for PROVIDER and STACK.

• 3 parallel linux:build jobs:
  • linux:build: [aws, monitoring]
  • linux:build: [aws, app1]
  • linux:build: [aws, app2]
• 4 parallel mac:build jobs:
  • mac:build: [gcp, data]
  • mac:build: [gcp, processing]
  • mac:build: [vultr, data]
  • mac:build: [vultr, processing]
• A linux:rspec job.
• A production job.

The jobs have three paths of execution:

• Linux path: The linux:rspec job runs as soon as the linux:build: [aws, app1] job finishes, without waiting for mac:build to finish.
• macOS path: The mac:rspec job runs as soon as the mac:build: [gcp, data] and mac:build: [vultr, data] jobs finish, without waiting for linux:build to finish.
• The production job runs as soon as all previous jobs finish.

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:

• rules
• only:variables
• except:variables

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.

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 == "schedule"
    - 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 14.9, GitLab provided a feature flag to let you use unsafe regexp syntax. We've fully migrated to RE2 now, and that feature flag is no longer available.

CI/CD variable expressions

• Introduced in GitLab 10.7 for the only and except CI keywords
• Expanded in GitLab 12.3 with the rules keyword

Use variable expressions to control which jobs are created in a pipeline after changes are pushed to GitLab. You can use variable expressions with:

• rules:if.
• only:variables and except:variables.

For example, with rules:if:

job1:
  variables:
    VAR1: "variable1"
  script:
    - echo "Test variable comparison
  rules:
    - if: $VAR1 == "variable1"

Compare a variable to a string

You can use the equality operators == and != to compare a variable with a string. Both single quotes and double quotes are valid. The order doesn't matter, so the variable can be first, or the string can be first. For example:

• if: $VARIABLE == "some value"
• if: $VARIABLE != "some value"
• if: "some value" == $VARIABLE

Compare two variables

You can compare the values of two variables. For example:

• if: $VARIABLE_1 == $VARIABLE_2
• if: $VARIABLE_1 != $VARIABLE_2

Check if a variable is undefined

You can compare a variable to the null keyword to see if it is defined. For example:

• if: $VARIABLE == null
• if: $VARIABLE != null

Check if a variable is empty

You can check if a variable is defined but empty. For example:

• if: $VARIABLE == ""
• if: $VARIABLE != ""

Check if a variable exists

You can check for the existence of a variable by using just the variable name in the expression. The variable must not be empty. For example:

• if: $VARIABLE

Compare a variable to a regex pattern

You can do regex pattern matching on variable values with the =~ and !~ operators. Variable pattern matching with regular expressions uses the RE2 regular expression syntax.

Expressions evaluate as true if:

• Matches are found when using =~.
• Matches are not found when using !~.

For example:

• if: $VARIABLE =~ /^content.*/
• if: $VARIABLE !~ /^content.*/

Single-character regular expressions, like /./, are not supported and produce an invalid expression syntax error.

Pattern matching is case-sensitive by default. Use the i flag modifier to make a pattern case-insensitive. For example: /pattern/i.

NOTE: When using the =~ character, make sure the right side of the comparison always contains a valid regular expression. If the right side of the comparison is not a valid regular expression enclosed with / characters, the expression evaluates in an unexpected way. In that case, the comparison checks if the left side is a substring of the right side. For example, "23" =~ "1234" evaluates to true, which is the opposite of "23" =~ /1234/, which evaluates to false. You should not configure your pipeline to rely on this behavior.

Store the regex pattern in a variable

• Introduced in GitLab 15.0 with a flag named ci_fix_rules_if_comparison_with_regexp_variable, disabled by default.
• Generally available and feature flag ci_fix_rules_if_comparison_with_regexp_variable removed in GitLab 15.1.

Variables on the right side of =~ and !~ expressions are evaluated as regular expressions. The regular expression must be enclosed in forward slashes (/). For example:

variables:
  pattern: '/^ab.*/'

regex-job1:
  variables:
    teststring: 'abcde'
  script: echo "This job will run, because 'abcde' matches the /^ab.*/ pattern."
  rules:
    - if: '$teststring =~ $pattern'

regex-job2:
  variables:
    teststring: 'fghij'
  script: echo "This job will not run, because 'fghi' does not match the /^ab.*/ pattern."
  rules:
    - if: '$teststring =~ $pattern'

Join variable expressions together with && or ||

• Introduced in GitLab 12.0

You can join multiple expressions using && (and) or || (or), for example:

• $VARIABLE1 =~ /^content.*/ && $VARIABLE2 == "something"
• $VARIABLE1 =~ /^content.*/ && $VARIABLE2 =~ /thing$/ && $VARIABLE3
• $VARIABLE1 =~ /^content.*/ || $VARIABLE2 =~ /thing$/ && $VARIABLE3

The precedence of operators follows the Ruby 2.5 standard, so && is evaluated before ||.

Group variable expressions together with parentheses

• Introduced in GitLab 13.3.
• Feature flag removed in GitLab 13.5.

You can use parentheses to group expressions together. Parentheses take precedence over && and ||, so expressions enclosed in parentheses are evaluated first, and the result is used for the rest of the expression.

You can nest parentheses to create complex conditions, and the inner-most expressions in parentheses are evaluated first.

For example:

• ($VARIABLE1 =~ /^content.*/ || $VARIABLE2) && ($VARIABLE3 =~ /thing$/ || $VARIABLE4)
• ($VARIABLE1 =~ /^content.*/ || $VARIABLE2 =~ /thing$/) && $VARIABLE3
• $CI_COMMIT_BRANCH == "my-branch" || (($VARIABLE1 == "thing" || $VARIABLE2 == "thing") && $VARIABLE3)