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Complex Expr

This example showcases how to string together complex expressions. This example is a python replica of https://github.com/argoproj/argo-workflows/blob/main/examples/expression-reusing-verbose-snippets.yaml

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import base64
import json

from hera.expr import C, g, it, sprig
from hera.workflows import Container, Env, Parameter, Workflow


def base64_encode(input: str) -> str:
    return base64.b64encode(input.encode()).decode()


data = json.dumps({"temps": [34, 27, 15, 57, 46]})
encoded_data = json.dumps({"weekWeather": base64_encode(data)})


def construct_weekly_temps():
    weather = g.workflow.parameters.weather
    week_weather = sprig.b64dec(weather.jsonpath("$.weekWeather"))
    temps = C([week_weather.jsonpath("$.temps")])
    iterators = [it[i] for i in range(5)]
    return temps.map(
        C(
            {
                "avg": sprig.add(*iterators) / 5,
                "min": sprig.min(*iterators),
                "max": sprig.max(*iterators),
            }
        ).to_json()
    )[0]


with Workflow(
    generate_name="expression-reusing-verbose-snippets-",
    entrypoint="c",
    arguments=Parameter(name="weather", value=encoded_data),
) as w:
    week_temps = construct_weekly_temps()
    week_temps_jsonpath = g.inputs.parameters["week-temps"].jsonpath
    c = Container(
        name="c",
        inputs=[Parameter(name="week-temps", value=f"{week_temps:=}")],
        env=[
            Env(name="MIN", value=f"{week_temps_jsonpath('$.min'):=}"),
            Env(name="MAX", value=f"{week_temps_jsonpath('$.max'):=}"),
            Env(name="AVG", value=f"{week_temps_jsonpath('$.avg'):=}"),
        ],
        command=["echo", "The week's average temperature was $AVG with a minimum of $MIN and a maximum of $MAX."],
        image="alpine:3.7",
    )

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apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: expression-reusing-verbose-snippets-
spec:
  arguments:
    parameters:
    - name: weather
      value: '{"weekWeather": "eyJ0ZW1wcyI6IFszNCwgMjcsIDE1LCA1NywgNDZdfQ=="}'
  entrypoint: c
  templates:
  - container:
      command:
      - echo
      - The week's average temperature was $AVG with a minimum of $MIN and a maximum
        of $MAX.
      env:
      - name: MIN
        value: '{{=jsonpath(inputs.parameters[''week-temps''], ''$.min'')}}'
      - name: MAX
        value: '{{=jsonpath(inputs.parameters[''week-temps''], ''$.max'')}}'
      - name: AVG
        value: '{{=jsonpath(inputs.parameters[''week-temps''], ''$.avg'')}}'
      image: alpine:3.7
    inputs:
      parameters:
      - name: week-temps
        value: '{{=map([jsonpath(sprig.b64dec(jsonpath(workflow.parameters.weather,
          ''$.weekWeather'')), ''$.temps'')], {toJson({''avg'': sprig.add(#[0], #[1],
          #[2], #[3], #[4]) / 5, ''min'': sprig.min(#[0], #[1], #[2], #[3], #[4]),
          ''max'': sprig.max(#[0], #[1], #[2], #[3], #[4])})})[0]}}'
    name: c

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