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New Decorators Fanout Loop

This example shows how to pass extra Step/Task kwargs when calling a function.

This lets you perform fanouts using with_items, set conditions using when and more.

Warning

These features are not compatible with local-running of dags and steps, please see https://github.com/argoproj-labs/hera/issues/1492.

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from hera.shared import global_config
from hera.workflows import Input, Workflow

global_config.experimental_features["decorator_syntax"] = True


w = Workflow(
    generate_name="fanout-workflow-",
)


class PrintMessageInput(Input):
    message: str = ""
    an_int: int = 42


@w.script()
def print_message(inputs: PrintMessageInput):
    print(inputs.message)


@w.script()
def print_int(inputs: PrintMessageInput):
    print(inputs.an_int)


@w.set_entrypoint
@w.steps()
def loop_example():
    print_message(
        PrintMessageInput(message="{{item}}"),
        name="print-str-message-loop-with-items",
        with_items=["hello world", "goodbye world"],
    )
    # For general use of loops in decorator functions, you will need to
    # use `.construct` to pass the `"{{item}}"` string.
    print_int(
        PrintMessageInput.construct(an_int="{{item}}"),
        name="print-int-loop-with-items",
        with_items=[42, 123, 321],
    )

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apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: fanout-workflow-
spec:
  entrypoint: loop-example
  templates:
  - name: print-message
    inputs:
      parameters:
      - name: message
        default: ''
      - name: an_int
        default: '42'
    script:
      image: python:3.9
      source: '{{inputs.parameters}}'
      args:
      - -m
      - hera.workflows.runner
      - -e
      - examples.workflows.experimental.new_decorators_fanout_loop:print_message
      command:
      - python
      env:
      - name: hera__script_pydantic_io
        value: ''
  - name: print-int
    inputs:
      parameters:
      - name: message
        default: ''
      - name: an_int
        default: '42'
    script:
      image: python:3.9
      source: '{{inputs.parameters}}'
      args:
      - -m
      - hera.workflows.runner
      - -e
      - examples.workflows.experimental.new_decorators_fanout_loop:print_int
      command:
      - python
      env:
      - name: hera__script_pydantic_io
        value: ''
  - name: loop-example
    steps:
    - - name: print-str-message-loop-with-items
        template: print-message
        withItems:
        - hello world
        - goodbye world
        arguments:
          parameters:
          - name: message
            value: '{{item}}'
          - name: an_int
            value: '42'
    - - name: print-int-loop-with-items
        template: print-int
        withItems:
        - 42
        - 123
        - 321
        arguments:
          parameters:
          - name: message
            value: ''
          - name: an_int
            value: '{{item}}'

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