DOCS.md

Use this plugin to build and push Docker images to the Google Container Registry (GCR). Please read the GCR documentation before you begin. You will need to generate a JSON token to authenticate to the registry and push images.

The following parameters are used to configure this plugin:

• registry - authenticates to this registry (defaults to gcr.io)
• token - json token
• repo - repository name for the image
• tag - repository tag for the image (defaults to latest)
• storage_driver - use aufs, devicemapper, btrfs or overlay driver

Sample configuration:

publish:
  gcr:
    repo: foo/bar
    token: >
      {
        "private_key_id": "...",
        "private_key": "...",
        "client_email": "...",
        "client_id": "...",
        "type": "..."
      }

Sample configuration using multiple tags:

publish:
  gcr:
    repo: foo/bar
    tag:
      - latest
      - "1.0.1"
      - "1.0"
    token: >
      {
        "private_key_id": "...",
        "private_key": "...",
        "client_email": "...",
        "client_id": "...",
        "type": "..."
      }

JSON Token

When setting your token in the .drone.yml file you must use folded block scalars to avoid parsing errors:

publish:
  gcr:
    token: >
      {
        "private_key_id": "...",
        "private_key": "...",
        "client_email": "...",
        "client_id": "...",
        "type": "..."
      }

When injecting secrets you must also use a folded block scalar:

publish:
  gcr:
    token: >
      $$GOOGLE_KEY

When defining secrets in a .drone.sec file you must also use folded block scalars. Please note that you should either place your JSON string on a single line:

environment:
  GOOGLE_KEY: >
    { "private_key_id": "...", "private_key": "..." ... }

Or you must ensure all lines have the exact same indentation:

environment:
  GOOGLE_KEY: >
    {
    "private_key_id": "...",
    "private_key": "...",
    "client_email": "...",
    "client_id": "...",
    "type": "..."
    }

Troubleshooting

For detailed output you can set the DOCKER_LAUNCH_DEBUG environment variable in your plugin configuration. This starts Docker with verbose logging enabled.

publish:
  gcr:
    environment:
      - DOCKER_LAUNCH_DEBUG=true

Known Issues

There are known issues when attempting to run this plugin on CentOS, RedHat, and Linux installations that do not have a supported storage driver installed. You can check by running docker info | grep 'Storage Driver:' on your host machine. If the storage driver is not aufs or overlay you will need to re-configure your host machine.

This error occurs when trying to use the default aufs storage Driver but aufs is not installed:

level=fatal msg="Error starting daemon: error initializing graphdriver: driver not supported

This error occurs when trying to use the overlay storage Driver but overlay is not installed:

level=error msg="'overlay' not found as a supported filesystem on this host.
Please ensure kernel is new enough and has overlay support loaded." 
level=fatal msg="Error starting daemon: error initializing graphdriver: driver not supported"

This error occurs when using CentOS or RedHat which default to the devicemapper storage driver:

level=error msg="There are no more loopback devices available." 
level=fatal msg="Error starting daemon: error initializing graphdriver: loopback mounting failed" 
Cannot connect to the Docker daemon. Is 'docker -d' running on this host?

The above issue can be resolved by setting storage_driver: vfs in the .drone.yml file. This may work, but will have very poor performance as discussed here.