As your configuration files become more complex, you may find they become more difficult to manage and update. Drone provides command-line support and plugin support for Jsonnet, a data templating language, which can help simplify complex yaml files. Jsonnet provides support for functions, variables, mixins, imports and more.
Example Jsonnet file uses a function to create step based on input parameters. This can be used to avoid copy/paste duplication of steps in your configuration:
local docker(name, branch, tag) = {
name: name,
image: "plugins/docker",
settings: {
repo: "octocat/hello-world",
tags: tag,
when: {
branch: branch
}
}
};
{
kind: "pipeline",
name: "default",
steps: [
{
name: "build",
image: "golang",
commands: [ "go build", "go test" ],
},
docker("build-master", "master", "latest"),
docker("build-develop", "develop", "develop"),
]
}
The above Jsonnet file can be convereted to a Yaml configuration file using the official Jsonnet command line utility or by using the Drone Command Line utility:
$ drone jsonnet --stdout
---
kind: pipeline
name: default
platform:
os: linux
arch: amd64
steps:
- name: build
image: golang
commands:
- go build
- go test
- name: build-master
image: plugins/docker
settings:
repo: octocat/hello-world
tags: latest
when:
branch: master
- name: build-develop
image: plugins/docker
settings:
repo: octocat/hello-world
tags: develop
when:
branch: develop
...
Drone can natively parse jsonnet files if you enable the below configuration parameter. Note that includes and imports are not supported. You will also need to rename your configuration file to .drone.jsonnet and update your repository settings in the user interface accordingly.
DRONE_JSONNET_ENABLED=true
