Drone plugin to update Rancher app

Drone.io allows to run tests, build images and push them in a registry. To deploy the new image on Kubernetes, we can use this nice plugin that is able to change image in a deployment.

With Rancher, that can be a bit problematic as the given "answers" for an application is not set. So, using interface to update something can potentially reset some values in a Deployment.

"plugin-rancher" is made to hit Rancher API to change the answer as if you did it on Rancher UI. You don't need to use "drone-kubernetes" plugin.

Important this plugin only manages "answers" and not "YAML" configuration.

I'm not responsible for possible application breaks, failure and data loses - You must know what you do before to use the plugin - Please backup application and data before to try the plugin.

Usage

In your .drone.yml file, lets take the example of building an image, then push it to a registry. Then, we set the new image tag on the corresponding answer.

kind: pipeline
name: build-blog

steps:
- name: build-image
  image: plugin/docker
  settings:
    repo: foo/bar
    tags:
      - latest
      - ${DRONE_COMMIT_SHA}
- name: deploy
  image: metal3d/plugin-rancher:v1
  settings:
    api: https://rancher.url/v3
    project: Default
    app: myblog
    token:
      from_secret: rancher-token
    verify: false
    cluster: mycluster
    keys: "image.tag,other.value"
    values: "${DRONE_COMMIT_SHA},whatever"

This example will update the application named "myblog" in the "Default" project. It will merge your answers to the already existing values.

Changing a key in answers should be applied by Rancher to corresponding resources. You need to know how the Rancher application is deployed and which key to change.

Settings

The managed settings are:

• api that should be the Rancher API URL, the plugin is currently only compatible with tester v3 version
• verify (optional, default is "true") check API certificate
• cluster is the cluster name
• project (optional, default to "Default") is the project name where the application you want to manage resides
• app is the name of the application you want to update
• token is the token you generated in Rancher to make the plugin able to contact Rancher API, please use secret to not display the token in drone file
• keys ordered keys (comma separated) of the answer that you want to change, keep order following values
• values ordered values for corresponding keys to set

Future work

To not have break in future plugin upgrade, please consider to use fixed tags.

v1 will continue to use the same format and behavior. That should not break your deployment, but please make backups before testing the plugin, and especially when you upgrade the plugin version.

Changing to next releases as "v2" may break your application, one more time, make backups.