task-parameters.md

Task Parameters

Tasks can declare input parameters that must be supplied to the task during a TaskRun. Some example use-cases of this include:

• A task that needs to know what compilation flags to use when building an application.
• A task that needs to know what to name a built artifact.
• A task that supports several different strategies, and leaves the choice up to the other.

Usage

The following example shows how Tasks can be parameterized, and these parameters can be passed to the Task from a TaskRun.

Input parameters in the form of ${inputs.params.foo} are replaced inside of the build Steps.

The following Task declares an input parameter called 'flags', and uses it in the steps.args list.

apiVersion: pipeline.knative.dev/v1alpha1
kind: Task
metadata:
  name: task-with-parameters
spec:
  inputs:
    params:
      - name: flags
        value: string
  steps:
    - name: build
      image: my-builder
      args: ["build", "--flags=${inputs.params.flags}"]

The following TaskRun supplies a value for flags:

apiVersion: pipeline.knative.dev/v1alpha1
kind: TaskRun
metadata:
  name: run-with-parameters
spec:
  taskRef:
    name: task-with-parameters
  inputs:
    params:
      - name: "flags"
        value: "foo=bar,baz=bat"