# Services

Woodpecker provides a services section in the YAML file used for defining service containers.
The below configuration composes database and cache containers.

Services are accessed using custom hostnames.
In the example below, the MySQL service is assigned the hostname `database` and is available at `database:3306`.

```yaml
steps:
  build:
    image: golang
    commands:
      - go build
      - go test

services:
  database:
    image: mysql

  cache:
    image: redis
```

## Configuration

Service containers generally expose environment variables to customize service startup such as default usernames, passwords and ports. Please see the official image documentation to learn more.

```diff
services:
  database:
    image: mysql
+   environment:
+     - MYSQL_DATABASE=test
+     - MYSQL_ALLOW_EMPTY_PASSWORD=yes

  cache:
    image: redis
```

## Detachment

Service and long running containers can also be included in the pipeline section of the configuration using the detach parameter without blocking other steps. This should be used when explicit control over startup order is required.

```diff
steps:
  build:
    image: golang
    commands:
      - go build
      - go test

  database:
    image: redis
+   detach: true

  test:
    image: golang
    commands:
      - go test
```

Containers from detached steps will terminate when the pipeline ends.

## Initialization

Service containers require time to initialize and begin to accept connections. If you are unable to connect to a service you may need to wait a few seconds or implement a backoff.

```diff
steps:
  test:
    image: golang
    commands:
+     - sleep 15
      - go get
      - go test

services:
  database:
    image: mysql
```

## Complete Pipeline Example

```yaml
services:
  database:
    image: mysql
    environment:
      - MYSQL_DATABASE=test
      - MYSQL_ROOT_PASSWORD=example
steps:
  get-version:
    image: ubuntu
    commands:
      - ( apt update && apt dist-upgrade -y && apt install -y mysql-client 2>&1 )> /dev/null
      - sleep 30s # need to wait for mysql-server init
      - echo 'SHOW VARIABLES LIKE "version"' | mysql -uroot -hdatabase test -pexample
```
