woodpecker/docs/build/matrix.md

Matrix Builds

Drone uses the matrix section of the .drone.yml to define the build matrix. Drone executes a build for each permutation in the matrix, allowing you to build and test a single commit against many configurations.

Below is an example .drone.yml that tests a single commit against multiple versions of Go and Redis, resulting in a total of 6 different build permutations:

build:
  image: golang:$$GO_VERSION
  commands:
    - go get
    - go build
    - go test

compose:
  redis:
    image: redis:$$REDIS_VERSION

matrix:
  GO_VERSION:
    - 1.4
    - 1.3
  REDIS_VERSION:
    - 2.6
    - 2.8
    - 3.0

Matrix Variables

Matrix variables are injected into the .drone.yml file using the $$ syntax, performing a simple find / replace. Matrix variables are also injected into your build container as environment variables.

This is an example .drone.yml file before injecting the matrix parameters:

build:
  image: golang:$$GO_VERSION
  commands:
    - go get
    - go build
    - go test

compose:
  redis:
    image: redis:$$REDIS_VERSION

    matrix:
      GO_VERSION:
        - 1.4
      REDIS_VERSION:
        - 3.0

And this is the .drone.yml file after injecting the matrix parameters:

build:
  image: golang:1.4
  environment:
    - GO_VERSION=1.4
    - REDIS_VERSION=3.0
  commands:
    - go get
    - go build
    - go test
    compose:
      redis:
        image: redis:3.0

Matrix Deployments

Matrix builds execute the same .drone.yml multiple times, but with different parameters. This means that publish and deployment steps are executed multiple times as well, which is typically undesired. To restrict a publish or deployment step to a single permutation you can add the following condition:

deploy:
  heroku:
    app: foo
    when:
      matrix:
        GO_VERSION: 1.4
        REDIS_VERSION: 3.0