Listing environment variables used to trigger a Buildkite pipeline

If you're using Buildkite for your builds, you may sometimes want to work out what environment variables were used to trigger a given build.

Although the Web UI allows you to see the environment variables a given step in the build takes, you can't see the job's environment variables itself, which can be frustrating if you're using them to allow parameterising your builds.

Fortunately, Buildkite provides a GraphQL API, so we can run the following query:

query environmentVariables {
  build(slug: "example/something/1234") {
     env
  }
}

This would then output, for instance:

{
  "data": {
    "build": {
      "env": [
        "USER=jamie.tanna",
        "AWS_REGION=eu-west-1"
      ]
    }
  }
}