gitlab-org--gitlab-foss/doc/ci/yaml
2017-01-26 15:53:39 +01:00
..
README.md Added hint about the execution order of before_script and artifact restoration. 2017-01-26 15:53:39 +01:00

Configuration of your builds with .gitlab-ci.yml

This document describes the usage of .gitlab-ci.yml, the file that is used by GitLab Runner to manage your project's builds.

If you want a quick introduction to GitLab CI, follow our quick start guide.

.gitlab-ci.yml

From version 7.12, GitLab CI uses a YAML file (.gitlab-ci.yml) for the project configuration. It is placed in the root of your repository and contains definitions of how your project should be built.

The YAML file defines a set of jobs with constraints stating when they should be run. The jobs are defined as top-level elements with a name and always have to contain at least the script clause:

job1:
  script: "execute-script-for-job1"

job2:
  script: "execute-script-for-job2"

The above example is the simplest possible CI configuration with two separate jobs, where each of the jobs executes a different command.

Of course a command can execute code directly (./configure;make;make install) or run a script (test.sh) in the repository.

Jobs are used to create builds, which are then picked up by Runners and executed within the environment of the Runner. What is important, is that each job is run independently from each other.

The YAML syntax allows for using more complex job specifications than in the above example:

image: ruby:2.1
services:
  - postgres

before_script:
  - bundle install

after_script:
  - rm secrets

stages:
  - build
  - test
  - deploy

job1:
  stage: build
  script:
    - execute-script-for-job1
  only:
    - master
  tags:
    - docker

There are a few reserved keywords that cannot be used as job names:

Keyword Required Description
image no Use docker image, covered in Use Docker
services no Use docker services, covered in Use Docker
stages no Define build stages
types no Alias for stages
before_script no Define commands that run before each job's script
after_script no Define commands that run after each job's script
variables no Define build variables
cache no Define list of files that should be cached between subsequent runs

image and services

This allows to specify a custom Docker image and a list of services that can be used for time of the build. The configuration of this feature is covered in a separate document.

before_script

before_script is used to define the command that should be run before all builds, including deploy builds, but after the restoration of artifacts. This can be an array or a multi-line string.

after_script

Introduced in GitLab 8.7 and requires Gitlab Runner v1.2

after_script is used to define the command that will be run after for all builds. This has to be an array or a multi-line string.

stages

stages is used to define build stages that can be used by jobs. The specification of stages allows for having flexible multi stage pipelines.

The ordering of elements in stages defines the ordering of builds' execution:

  1. Builds of the same stage are run in parallel.
  2. Builds of the next stage are run after the jobs from the previous stage complete successfully.

Let's consider the following example, which defines 3 stages:

stages:
  - build
  - test
  - deploy
  1. First all jobs of build are executed in parallel.
  2. If all jobs of build succeed, the test jobs are executed in parallel.
  3. If all jobs of test succeed, the deploy jobs are executed in parallel.
  4. If all jobs of deploy succeed, the commit is marked as success.
  5. If any of the previous jobs fails, the commit is marked as failed and no jobs of further stage are executed.

There are also two edge cases worth mentioning:

  1. If no stages are defined in .gitlab-ci.yml, then by default the build, test and deploy are allowed to be used as job's stage by default.
  2. If a job doesn't specify a stage, the job is assigned the test stage.

types

Alias for stages.

variables

Introduced in GitLab Runner v0.5.0.

GitLab CI allows you to add variables to .gitlab-ci.yml that are set in the build environment. The variables are stored in the Git repository and are meant to store non-sensitive project configuration, for example:

variables:
  DATABASE_URL: "postgres://postgres@postgres/my_database"

These variables can be later used in all executed commands and scripts. The YAML-defined variables are also set to all created service containers, thus allowing to fine tune them. Variables can be also defined on a job level.

Except for the user defined variables, there are also the ones set up by the Runner itself. One example would be CI_BUILD_REF_NAME which has the value of the branch or tag name for which project is built. Apart from the variables you can set in .gitlab-ci.yml, there are also the so called secret variables which can be set in GitLab's UI.

Learn more about variables.

cache

Introduced in GitLab Runner v0.7.0.

cache is used to specify a list of files and directories which should be cached between builds. You can only use paths that are within the project workspace.

By default the caching is enabled per-job and per-branch.

If cache is defined outside the scope of the jobs, it means it is set globally and all jobs will use its definition.

Cache all files in binaries and .config:

rspec:
  script: test
  cache:
    paths:
    - binaries/
    - .config

Cache all Git untracked files:

rspec:
  script: test
  cache:
    untracked: true

Cache all Git untracked files and files in binaries:

rspec:
  script: test
  cache:
    untracked: true
    paths:
    - binaries/

Locally defined cache overwrites globally defined options. This will cache only binaries/:

cache:
  paths:
  - my/files

rspec:
  script: test
  cache:
    paths:
    - binaries/

The cache is provided on a best-effort basis, so don't expect that the cache will be always present. For implementation details, please check GitLab Runner.

cache:key

Introduced in GitLab Runner v1.0.0.

The key directive allows you to define the affinity of caching between jobs, allowing to have a single cache for all jobs, cache per-job, cache per-branch or any other way you deem proper.

This allows you to fine tune caching, allowing you to cache data between different jobs or even different branches.

The cache:key variable can use any of the predefined variables.


Example configurations

To enable per-job caching:

cache:
  key: "$CI_BUILD_NAME"
  untracked: true

To enable per-branch caching:

cache:
  key: "$CI_BUILD_REF_NAME"
  untracked: true

To enable per-job and per-branch caching:

cache:
  key: "$CI_BUILD_NAME/$CI_BUILD_REF_NAME"
  untracked: true

To enable per-branch and per-stage caching:

cache:
  key: "$CI_BUILD_STAGE/$CI_BUILD_REF_NAME"
  untracked: true

If you use Windows Batch to run your shell scripts you need to replace $ with %:

cache:
  key: "%CI_BUILD_STAGE%/%CI_BUILD_REF_NAME%"
  untracked: true

Jobs

.gitlab-ci.yml allows you to specify an unlimited number of jobs. Each job must have a unique name, which is not one of the Keywords mentioned above. A job is defined by a list of parameters that define the build behavior.

job_name:
  script:
    - rake spec
    - coverage
  stage: test
  only:
    - master
  except:
    - develop
  tags:
    - ruby
    - postgres
  allow_failure: true
Keyword Required Description
script yes Defines a shell script which is executed by Runner
image no Use docker image, covered in Using Docker Images
services no Use docker services, covered in Using Docker Images
stage no Defines a build stage (default: test)
type no Alias for stage
variables no Define build variables on a job level
only no Defines a list of git refs for which build is created
except no Defines a list of git refs for which build is not created
tags no Defines a list of tags which are used to select Runner
allow_failure no Allow build to fail. Failed build doesn't contribute to commit status
when no Define when to run build. Can be on_success, on_failure, always or manual
dependencies no Define other builds that a build depends on so that you can pass artifacts between them
artifacts no Define list of build artifacts
cache no Define list of files that should be cached between subsequent runs
before_script no Override a set of commands that are executed before build
after_script no Override a set of commands that are executed after build
environment no Defines a name of environment to which deployment is done by this build

script

script is a shell script which is executed by the Runner. For example:

job:
  script: "bundle exec rspec"

This parameter can also contain several commands using an array:

job:
  script:
    - uname -a
    - bundle exec rspec

Sometimes, script commands will need to be wrapped in single or double quotes. For example, commands that contain a colon (:) need to be wrapped in quotes so that the YAML parser knows to interpret the whole thing as a string rather than a "key: value" pair. Be careful when using special characters (:, {, }, [, ], ,, &, *, #, ?, |, -, <, >, =, !, %, @, `).

stage

stage allows to group build into different stages. Builds of the same stage are executed in parallel. For more info about the use of stage please check stages.

only and except

only and except are two parameters that set a refs policy to limit when jobs are built:

  1. only defines the names of branches and tags for which the job will be built.
  2. except defines the names of branches and tags for which the job will not be built.

There are a few rules that apply to the usage of refs policy:

  • only and except are inclusive. If both only and except are defined in a job specification, the ref is filtered by only and except.
  • only and except allow the use of regular expressions.
  • only and except allow the use of special keywords: branches, tags, and triggers.
  • only and except allow to specify a repository path to filter jobs for forks.

In the example below, job will run only for refs that start with issue-, whereas all branches will be skipped.

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

In this example, job will run only for refs that are tagged, or if a build is explicitly requested via an API trigger.

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

The repository path can be used to have jobs executed only for the parent repository and not forks:

job:
  only:
    - branches@gitlab-org/gitlab-ce
  except:
    - master@gitlab-org/gitlab-ce

The above example will run job for all branches on gitlab-org/gitlab-ce, except master.

job variables

It is possible to define build variables using a variables keyword on a job level. It works basically the same way as its global-level equivalent but allows you to define job-specific build variables.

When the variables keyword is used on a job level, it overrides global YAML build variables and predefined variables. To turn off global defined variables in your job, define an empty array:

job_name:
  variables: []

Build variables priority is defined in the variables documentation.

tags

tags is used to select specific Runners from the list of all Runners that are allowed to run this project.

During the registration of a Runner, you can specify the Runner's tags, for example ruby, postgres, development.

tags allow you to run builds with Runners that have the specified tags assigned to them:

job:
  tags:
    - ruby
    - postgres

The specification above, will make sure that job is built by a Runner that has both ruby AND postgres tags defined.

allow_failure

allow_failure is used when you want to allow a build to fail without impacting the rest of the CI suite. Failed builds don't contribute to the commit status.

When enabled and the build fails, the pipeline will be successful/green for all intents and purposes, but a "CI build passed with warnings" message will be displayed on the merge request or commit or build page. This is to be used by builds that are allowed to fail, but where failure indicates some other (manual) steps should be taken elsewhere.

In the example below, job1 and job2 will run in parallel, but if job1 fails, it will not stop the next stage from running, since it's marked with allow_failure: true:

job1:
  stage: test
  script:
  - execute_script_that_will_fail
  allow_failure: true

job2:
  stage: test
  script:
  - execute_script_that_will_succeed

job3:
  stage: deploy
  script:
  - deploy_to_staging

when

when is used to implement jobs that are run in case of failure or despite the failure.

when can be set to one of the following values:

  1. on_success - execute build only when all builds from prior stages succeed. This is the default.
  2. on_failure - execute build only when at least one build from prior stages fails.
  3. always - execute build regardless of the status of builds from prior stages.
  4. manual - execute build manually (added in GitLab 8.10). Read about manual actions below.

For example:

stages:
- build
- cleanup_build
- test
- deploy
- cleanup

build_job:
  stage: build
  script:
  - make build

cleanup_build_job:
  stage: cleanup_build
  script:
  - cleanup build when failed
  when: on_failure

test_job:
  stage: test
  script:
  - make test

deploy_job:
  stage: deploy
  script:
  - make deploy
  when: manual

cleanup_job:
  stage: cleanup
  script:
  - cleanup after builds
  when: always

The above script will:

  1. Execute cleanup_build_job only when build_job fails.
  2. Always execute cleanup_job as the last step in pipeline regardless of success or failure.
  3. Allow you to manually execute deploy_job from GitLab's UI.

Manual actions

Introduced in GitLab 8.10.

Manual actions are a special type of job that are not executed automatically; they need to be explicitly started by a user. Manual actions can be started from pipeline, build, environment, and deployment views. You can execute the same manual action multiple times.

An example usage of manual actions is deployment to production.

Read more at the environments documentation.

environment

Introduced in GitLab 8.9.

You can read more about environments and find more examples in the documentation about environments.

environment is used to define that a job deploys to a specific environment. If environment is specified and no environment under that name exists, a new one will be created automatically.

In its simplest form, the environment keyword can be defined like:

deploy to production:
  stage: deploy
  script: git push production HEAD:master
  environment:
    name: production

In the above example, the deploy to production job will be marked as doing a deployment to the production environment.

environment:name

Introduced in GitLab 8.11.

Note: Before GitLab 8.11, the name of an environment could be defined as a string like environment: production. The recommended way now is to define it under the name keyword.

The environment name can contain:

  • letters
  • digits
  • spaces
  • -
  • _
  • /
  • $
  • {
  • }

Common names are qa, staging, and production, but you can use whatever name works with your workflow.

Instead of defining the name of the environment right after the environment keyword, it is also possible to define it as a separate value. For that, use the name keyword under environment:

deploy to production:
  stage: deploy
  script: git push production HEAD:master
  environment:
    name: production

environment:url

Introduced in GitLab 8.11.

Note: Before GitLab 8.11, the URL could be added only in GitLab's UI. The recommended way now is to define it in .gitlab-ci.yml.

This is an optional value that when set, it exposes buttons in various places in GitLab which when clicked take you to the defined URL.

In the example below, if the job finishes successfully, it will create buttons in the merge requests and in the environments/deployments pages which will point to https://prod.example.com.

deploy to production:
  stage: deploy
  script: git push production HEAD:master
  environment:
    name: production
    url: https://prod.example.com

environment:on_stop

Notes:

  • Introduced in GitLab 8.13.
  • Starting with GitLab 8.14, when you have an environment that has a stop action defined, GitLab will automatically trigger a stop action when the associated branch is deleted.

Closing (stoping) environments can be achieved with the on_stop keyword defined under environment. It declares a different job that runs in order to close the environment.

Read the environment:action section for an example.

environment:action

Introduced in GitLab 8.13.

The action keyword is to be used in conjunction with on_stop and is defined in the job that is called to close the environment.

Take for instance:

review_app:
  stage: deploy
  script: make deploy-app
  environment:
    name: review
    on_stop: stop_review_app

stop_review_app:
  stage: deploy
  script: make delete-app
  when: manual
  environment:
    name: review
    action: stop

In the above example we set up the review_app job to deploy to the review environment, and we also defined a new stop_review_app job under on_stop. Once the review_app job is successfully finished, it will trigger the stop_review_app job based on what is defined under when. In this case we set it up to manual so it will need a manual action via GitLab's web interface in order to run.

The stop_review_app job is required to have the following keywords defined:

  • when - reference
  • environment:name
  • environment:action

dynamic environments

Introduced in GitLab 8.12 and GitLab Runner 1.6. $CI_ENVIRONMENT_SLUG was introduced in GitLab 8.15

environment can also represent a configuration hash with name and url. These parameters can use any of the defined CI variables (including predefined, secure variables and .gitlab-ci.yml variables).

For example:

deploy as review app:
  stage: deploy
  script: make deploy
  environment:
    name: review/$CI_BUILD_REF_NAME
    url: https://$CI_ENVIRONMENT_SLUG.example.com/

The deploy as review app job will be marked as deployment to dynamically create the review/$CI_BUILD_REF_NAME environment, where $CI_BUILD_REF_NAME is an environment variable set by the Runner. The $CI_ENVIRONMENT_SLUG variable is based on the environment name, but suitable for inclusion in URLs. In this case, if the deploy as review app job was run in a branch named pow, this environment would be accessible with an URL like https://review-pow-aaaaaa.example.com/.

This of course implies that the underlying server which hosts the application is properly configured.

The common use case is to create dynamic environments for branches and use them as Review Apps. You can see a simple example using Review Apps at https://gitlab.com/gitlab-examples/review-apps-nginx/.

artifacts

Notes:

  • Introduced in GitLab Runner v0.7.0 for non-Windows platforms.
  • Windows support was added in GitLab Runner v.1.0.0.
  • Currently not all executors are supported.
  • Build artifacts are only collected for successful builds by default.

artifacts is used to specify a list of files and directories which should be attached to the build after success. You can only use paths that are within the project workspace. To pass artifacts between different builds, see dependencies.

Below are some examples.

Send all files in binaries and .config:

artifacts:
  paths:
  - binaries/
  - .config

Send all Git untracked files:

artifacts:
  untracked: true

Send all Git untracked files and files in binaries:

artifacts:
  untracked: true
  paths:
  - binaries/

To disable artifact passing, define the job with empty dependencies:

job:
  stage: build
  script: make build
  dependencies: []

You may want to create artifacts only for tagged releases to avoid filling the build server storage with temporary build artifacts.

Create artifacts only for tags (default-job will not create artifacts):

default-job:
  script:
    - mvn test -U
  except:
    - tags

release-job:
  script:
    - mvn package -U
  artifacts:
    paths:
    - target/*.war
  only:
    - tags

The artifacts will be sent to GitLab after a successful build and will be available for download in the GitLab UI.

artifacts:name

Introduced in GitLab 8.6 and GitLab Runner v1.1.0.

The name directive allows you to define the name of the created artifacts archive. That way, you can have a unique name for every archive which could be useful when you'd like to download the archive from GitLab. The artifacts:name variable can make use of any of the predefined variables. The default name is artifacts, which becomes artifacts.zip when downloaded.


Example configurations

To create an archive with a name of the current build:

job:
  artifacts:
    name: "$CI_BUILD_NAME"

To create an archive with a name of the current branch or tag including only the files that are untracked by Git:

job:
   artifacts:
     name: "$CI_BUILD_REF_NAME"
     untracked: true

To create an archive with a name of the current build and the current branch or tag including only the files that are untracked by Git:

job:
  artifacts:
    name: "${CI_BUILD_NAME}_${CI_BUILD_REF_NAME}"
    untracked: true

To create an archive with a name of the current stage and branch name:

job:
  artifacts:
    name: "${CI_BUILD_STAGE}_${CI_BUILD_REF_NAME}"
    untracked: true

If you use Windows Batch to run your shell scripts you need to replace $ with %:

job:
  artifacts:
    name: "%CI_BUILD_STAGE%_%CI_BUILD_REF_NAME%"
    untracked: true

artifacts:when

Introduced in GitLab 8.9 and GitLab Runner v1.3.0.

artifacts:when is used to upload artifacts on build failure or despite the failure.

artifacts:when can be set to one of the following values:

  1. on_success - upload artifacts only when the build succeeds. This is the default.
  2. on_failure - upload artifacts only when the build fails.
  3. always - upload artifacts regardless of the build status.

Example configurations

To upload artifacts only when build fails.

job:
  artifacts:
    when: on_failure

artifacts:expire_in

Introduced in GitLab 8.9 and GitLab Runner v1.3.0.

artifacts:expire_in is used to delete uploaded artifacts after the specified time. By default, artifacts are stored on GitLab forever. expire_in allows you to specify how long artifacts should live before they expire, counting from the time they are uploaded and stored on GitLab.

You can use the Keep button on the build page to override expiration and keep artifacts forever.

After expiry, artifacts are actually deleted hourly by default (via a cron job), but they are not accessible after expiry.

The value of expire_in is an elapsed time. Examples of parseable values:

  • '3 mins 4 sec'
  • '2 hrs 20 min'
  • '2h20min'
  • '6 mos 1 day'
  • '47 yrs 6 mos and 4d'
  • '3 weeks and 2 days'

Example configurations

To expire artifacts 1 week after being uploaded:

job:
  artifacts:
    expire_in: 1 week

dependencies

Introduced in GitLab 8.6 and GitLab Runner v1.1.1.

This feature should be used in conjunction with artifacts and allows you to define the artifacts to pass between different builds.

Note that artifacts from all previous stages are passed by default.

To use this feature, define dependencies in context of the job and pass a list of all previous builds from which the artifacts should be downloaded. You can only define builds from stages that are executed before the current one. An error will be shown if you define builds from the current stage or next ones. Defining an empty array will skip downloading any artifacts for that job.


In the following example, we define two jobs with artifacts, build:osx and build:linux. When the test:osx is executed, the artifacts from build:osx will be downloaded and extracted in the context of the build. The same happens for test:linux and artifacts from build:linux.

The job deploy will download artifacts from all previous builds because of the stage precedence:

build:osx:
  stage: build
  script: make build:osx
  artifacts:
    paths:
    - binaries/

build:linux:
  stage: build
  script: make build:linux
  artifacts:
    paths:
    - binaries/

test:osx:
  stage: test
  script: make test:osx
  dependencies:
  - build:osx

test:linux:
  stage: test
  script: make test:linux
  dependencies:
  - build:linux

deploy:
  stage: deploy
  script: make deploy

before_script and after_script

It's possible to overwrite globally defined before_script and after_script:

before_script:
- global before script

job:
  before_script:
  - execute this instead of global before script
  script:
  - my command
  after_script:
  - execute this after my script

Git Strategy

Introduced in GitLab 8.9 as an experimental feature. May change or be removed completely in future releases. GIT_STRATEGY=none requires GitLab Runner v1.7+.

You can set the GIT_STRATEGY used for getting recent application code, either in the global variables section or the variables section for individual jobs. If left unspecified, the default from project settings will be used.

There are three possible values: clone, fetch, and none.

clone is the slowest option. It clones the repository from scratch for every job, ensuring that the project workspace is always pristine.

variables:
  GIT_STRATEGY: clone

fetch is faster as it re-uses the project workspace (falling back to clone if it doesn't exist). git clean is used to undo any changes made by the last job, and git fetch is used to retrieve commits made since the last job ran.

variables:
  GIT_STRATEGY: fetch

none also re-uses the project workspace, but skips all Git operations (including GitLab Runner's pre-clone script, if present). It is mostly useful for jobs that operate exclusively on artifacts (e.g., deploy). Git repository data may be present, but it is certain to be out of date, so you should only rely on files brought into the project workspace from cache or artifacts.

variables:
  GIT_STRATEGY: none

Git Submodule Strategy

Requires GitLab Runner v1.10+.

The GIT_SUBMODULE_STRATEGY variable is used to control if / how Git submodules are included when fetching the code before a build. Like GIT_STRATEGY, it can be set in either the global variables section or the variables section for individual jobs.

There are three posible values: none, normal, and recursive:

  • none means that submodules will not be included when fetching the project code. This is the default, which matches the pre-v1.10 behavior.

  • normal means that only the top-level submodules will be included. It is equivalent to:

    $ git submodule sync
    $ git submodule update --init
    
  • recursive means that all submodules (including submodules of submodules) will be included. It is equivalent to:

    $ git submodule sync --recursive
    $ git submodule update --init --recursive
    

Note that for this feature to work correctly, the submodules must be configured (in .gitmodules) with either:

  • the HTTP(S) URL of a publicly-accessible repository, or
  • a relative path to another repository on the same GitLab server. See the Git submodules documentation.

Build stages attempts

Introduced in GitLab, it requires GitLab Runner v1.9+.

You can set the number for attempts the running build will try to execute each of the following stages:

Variable Description
GET_SOURCES_ATTEMPTS Number of attempts to fetch sources running a build
ARTIFACT_DOWNLOAD_ATTEMPTS Number of attempts to download artifacts running a build
RESTORE_CACHE_ATTEMPTS Number of attempts to restore the cache running a build

The default is one single attempt.

Example:

variables:
  GET_SOURCES_ATTEMPTS: "3"

You can set them in the global variables section or the variables section for individual jobs.

Shallow cloning

Introduced in GitLab 8.9 as an experimental feature. May change in future releases or be removed completely.

You can specify the depth of fetching and cloning using GIT_DEPTH. This allows shallow cloning of the repository which can significantly speed up cloning for repositories with a large number of commits or old, large binaries. The value is passed to git fetch and git clone.

Note: If you use a depth of 1 and have a queue of builds or retry builds, jobs may fail.

Since Git fetching and cloning is based on a ref, such as a branch name, runners can't clone a specific commit SHA. If there are multiple builds in the queue, or you are retrying an old build, the commit to be tested needs to be within the git history that is cloned. Setting too small a value for GIT_DEPTH can make it impossible to run these old commits. You will see unresolved reference in build logs. You should then reconsider changing GIT_DEPTH to a higher value.

Builds that rely on git describe may not work correctly when GIT_DEPTH is set since only part of the git history is present.

To fetch or clone only the last 3 commits:

variables:
  GIT_DEPTH: "3"

Hidden keys

Introduced in GitLab 8.6 and GitLab Runner v1.1.1.

Keys that start with a dot (.) will be not processed by GitLab CI. You can use this feature to ignore jobs, or use the special YAML features and transform the hidden keys into templates.

In the following example, .key_name will be ignored:

.key_name:
  script:
    - rake spec

Hidden keys can be hashes like normal CI jobs, but you are also allowed to use different types of structures to leverage special YAML features.

Special YAML features

It's possible to use special YAML features like anchors (&), aliases (*) and map merging (<<), which will allow you to greatly reduce the complexity of .gitlab-ci.yml.

Read more about the various YAML features.

Anchors

Introduced in GitLab 8.6 and GitLab Runner v1.1.1.

YAML also has a handy feature called 'anchors', which let you easily duplicate content across your document. Anchors can be used to duplicate/inherit properties, and is a perfect example to be used with hidden keys to provide templates for your jobs.

The following example uses anchors and map merging. It will create two jobs, test1 and test2, that will inherit the parameters of .job_template, each having their own custom script defined:

.job_template: &job_definition  # Hidden key that defines an anchor named 'job_definition'
  image: ruby:2.1
  services:
    - postgres
    - redis

test1:
  <<: *job_definition           # Merge the contents of the 'job_definition' alias
  script:
    - test1 project

test2:
  <<: *job_definition           # Merge the contents of the 'job_definition' alias
  script:
    - test2 project

& sets up the name of the anchor (job_definition), << means "merge the given hash into the current one", and * includes the named anchor (job_definition again). The expanded version looks like this:

.job_template:
  image: ruby:2.1
  services:
    - postgres
    - redis

test1:
  image: ruby:2.1
  services:
    - postgres
    - redis
  script:
    - test1 project

test2:
  image: ruby:2.1
  services:
    - postgres
    - redis
  script:
    - test2 project

Let's see another one example. This time we will use anchors to define two sets of services. This will create two jobs, test:postgres and test:mysql, that will share the script directive defined in .job_template, and the services directive defined in .postgres_services and .mysql_services respectively:

.job_template: &job_definition
  script:
    - test project

.postgres_services:
  services: &postgres_definition
    - postgres
    - ruby

.mysql_services:
  services: &mysql_definition
    - mysql
    - ruby

test:postgres:
  <<: *job_definition
  services: *postgres_definition

test:mysql:
  <<: *job_definition
  services: *mysql_definition

The expanded version looks like this:

.job_template:
  script:
    - test project

.postgres_services:
  services:
    - postgres
    - ruby

.mysql_services:
  services:
    - mysql
    - ruby

test:postgres:
  script:
    - test project
  services:
    - postgres
    - ruby

test:mysql:
  script:
    - test project
  services:
    - mysql
    - ruby

You can see that the hidden keys are conveniently used as templates.

Triggers

Triggers can be used to force a rebuild of a specific branch, tag or commit, with an API call.

Read more in the triggers documentation.

Validate the .gitlab-ci.yml

Each instance of GitLab CI has an embedded debug tool called Lint. You can find the link under /ci/lint of your gitlab instance.

Skipping builds

If your commit message contains [ci skip] or [skip ci], using any capitalization, the commit will be created but the builds will be skipped.

Examples

Visit the examples README to see a list of examples using GitLab CI with various languages.