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Functions

tip

We recommend reviewing Go Templates documentation before attempting to create a template.

If you're new to YAML we also recommend reviewing the YAML 1.2 spec for validation on syntax.

Overview​

Go provides a limited set of built-in template functions. Vela provides a number of additional, predefined functions to utilize in templates.

Built-in Functions​

See Go template Functions for a list of built-in functions.

Example​

A function call:

{{ printf "%q" "output" }}

A function call whose final argument comes from the previous command:

{{ "output" | printf "%q" }}

Custom Functions​

Sprig​

Sprig provides over 100 additional template functions. Please refer to the original Sprig function documentation.

To note, the env and expandenv functions are not available in Vela.

toYaml​

The toYaml function is intended to ease working with passing and rendering YAML content in Vela templates.

Example​

.vela.yml

version: "1"
templates:
  - name: golang
    source: github.com/<org>/<repo>/path/to/file/<template>.yml
    type: github

steps:
  - name: sample
    template:
      name: golang
      vars:
        ruleset:
          event: [ push, pull_request ]
          branch: [ main ]

github.com/<org>/<repo>/path/to/file/<template>.yml

metadata:
  template: true

steps:
  - name: install
    commands:
      - test
    image: alpine
    ruleset:
      {{- toYaml .ruleset | nindent 6 }}

With the pipeline and template above in place, the final resulting pipeline would render as follows:

version: "1"
steps:
  - name: sample_install
    commands:
      - test
    image: alpine
    ruleset:
      event: [ push, pull_request ]
      branch: [ main ]

vela​

The vela function provides the convenience of accessing Vela environment variables within your Vela templates. See its dedicated platform vars page for more info.