Platform Vars

tip

We recommend reviewing Starlark Spec before attempting to create a template.

Additionally, depending on how the template is written, it may be incompatible with viewing pipelines in the UI.

Overview

Platform variables can be referenced with the following syntax:

ctx['vela']['<resource>']['<name>']

Examples

• ctx["vela"]["repo"]["name"] equates to the VELA_REPO_NAME environment variable
• ctx["vela"]["build"]["number"] equates to the VELA_BUILD_NUMBER environment variable
• ctx["vela"]["system"]["addr"] equates to the VELA_ADDR environment variable
• ctx["vela"]["deployment"]["<name>"] equates to the DEPLOYMENT_PARAMETER_<name> environment variable

Sample

Let's take a look at using a platform variable within a template:

def main(ctx):
  return {
    'version': '1',
    'steps': [
      step(ctx["vela"]["repo"]["name"]),
    ],
  }

def step(name):
  return {
    "name": "echo %s" % name,
    "image": "alpine:latest",
    'commands': [
      "echo %s" % name
    ]
  }

The caller of this template could look like:

version: "1"
templates:
  - name: sample
    source: github.com/<org>/<repo>/path/to/file/<template>.star
    format: starlark
    type: github

steps:
  - name: build
    template:
      name: sample

Which means the compiled pipeline for execution on a worker is:

version: 1
steps:
  - name: sample_echo hello-world
    image: alpine:latest
    commands:
      - echo hello-world