Added docs for detach

[clayrisser]

https://discourse.drone.io/t/drone-event-system/1592/3

[jmccann]

I think this may be a dupe of #301

[bradrydzewski]

I feel like for documenting detached, we should use a simpler example, such as starting a mysql server in detached mode. Right now it introduces multiple concepts (detached mode and building and testing docker image) instead of focusing on the single topic of detached mode.

With that being said, I feel like there is a ton of value in having documentation for building, detaching and then testing a container. @tonglil perhaps we could benefit from a subsection of the docs that focuses solely on building, testing and publishing docker containers, since there are a few different methods. Thoughts?

[bradrydzewski]

EDIT: we had this documented in a prior version of the docs, but must have slipped through the cracks when we moved documentation sites. See below.

Service containers can also be included in the pipeline section of the Yaml using the detach parameter. This should be used when explicit control over startup order is required.

pipeline:
  build:
    image: golang
    commands:
      - go get
      - go build

  database:
    image: redis
+   detach: true

  test:
    image: golang
    commands:
      - go test

[clayrisser]

Where would you want me to document how to build, detach, and test a container? Btw, FYI, the docker plugin does not support a build separate from a push very well.

[bradrydzewski]

Where would you want me to document how to build, detach, and test a container

For now I would recommend adding to the FAQ section of the documentation. We can find a more permanent home for the documentation once we do some restructuring.
https://github.com/drone/docs/tree/master/content/faq

Btw, FYI, the docker plugin does not support a build separate from a push very well.

The docker plugin exists so that you can build and publish images safely using docker in docker, without having to insecurely expose the host machine docker socket. Using the plugin to build an image on the host machine is not a problem this plugin tries to solve. You are probably better off just doing something like this:

pipeline:
  build:
    image: docker
    commands: [ docker build -t foo . ]
    volumes: [ /var/run/docker.sock:/var/run/docker.sock ]

Note that we try to design plugins to do one thing, and do it well. So if a plugin does not handle your specific use case, you might want to consider creating your own custom plugin. Having many specialized plugins is encouraged, as opposed to having monolith plugins that do everything.

[clayrisser]

Ok, cool, I'll prob make a plugin for handling the individual docker pipeline steps.