# Configuration of your builds with .gitlab-ci.yml

From version 7.12, GitLab CI uses a [YAML](https://en.wikipedia.org/wiki/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 the `script` clause:

```yaml
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](../runners/README.md) and executed within the environment of the
runner. What is important, is that each job is run independently from each
other.

## .gitlab-ci.yml

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

```yaml
image: ruby:2.1
services:
  - postgres

before_script:
  - bundle_install

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](../docker/README.md) |
| services      | no | Use docker services, covered in [Use Docker](../docker/README.md) |
| stages        | no | Define build stages |
| types         | no | Alias for `stages` |
| before_script | no | Define commands that run before 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
separate document: [Use Docker](../docker/README.md).

### before_script

`before_script` is used to define the command that should be run before all
builds, including deploy builds. This can 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.
1. Builds of next stage are run after success.

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

```yaml
stages:
  - build
  - test
  - deploy
```

1. First all jobs of `build` are executed in parallel.
1. If all jobs of `build` succeeds, the `test` jobs are executed in parallel.
1. If all jobs of `test` succeeds, the `deploy` jobs are executed in parallel.
1. If all jobs of `deploy` succeeds, the commit is marked as `success`.
1. 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` is 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 `stage`, the job is assigned the `test` stage.

### types

Alias for [stages](#stages).

### variables

_**Note:** Introduced in GitLab Runner v0.5.0._

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

```yaml
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.

### cache

`cache` is used to specify a list of files and directories which should be
cached between builds. Caches are stored according to the branch/ref and the
job name. They are not currently shared between different job names or between
branches/refs, which means that caching will benefit you if you push subsequent
commits to an existing feature branch.

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

To cache all git untracked files and files in `binaries`:

```yaml
cache:
  untracked: true
  paths:
  - binaries/
```

## 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.

```yaml
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 |
| stage         | no (default: `test`) | Defines a build stage |
| type          | no | Alias for `stage` |
| 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` or `always` |
| artifacts     | no | Define list build artifacts |
| cache         | no | Define list of files that should be cached between subsequent runs |

### script

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

```yaml
job:
  script: "bundle exec rspec"
```

This parameter can also contain several commands using an array:

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

### 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](#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` and `tags`.
* `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.

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

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

```yaml
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.

### 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:

```yaml
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.

### 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
    succeeded. This is the default.
1. `on_failure` - execute build only when at least one build from prior stages
    failed.
1. `always` - execute build despite the status of builds from prior stages.

For example:

```yaml
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

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.

### artifacts

_**Note:** Introduced in GitLab Runner v0.7.0._

`artifacts` is used to specify list of files and directories which should be
attached to build after success. Below are some examples.

Send all files in `binaries` and `.config`:

```yaml
artifacts:
  paths:
  - binaries/
  - .config
```

Send all git untracked files:

```yaml
artifacts:
  untracked: true
```

Send all git untracked files and files in `binaries`:

```yaml
artifacts:
  untracked: true
  paths:
  - binaries/
```

The artifacts will be send after a successful build success to GitLab, and will
be accessible in the GitLab UI to download.

### cache

_**Note:** Introduced in GitLab Runner v0.7.0._

`cache` is used to specify list of files and directories which should be cached
between builds. Below are some examples:

Cache all files in `binaries` and `.config`:

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

Cache all git untracked files:

```yaml
rspec:
  script: test
  cache:
    untracked: true
```

Cache all git untracked files and files in `binaries`:

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

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

```yaml
cache:
  paths:
  - my/files

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

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

## 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]`, the commit will be created but the
builds will be skipped.
