expression-reusing-verbose-snippets.yaml

# Expressions do not support variables. Rather than repeating verbose expressions to reuse output, you can map over the
# expression output and use its value which is aliased as `#`. Then you can place your "variables" in a JSON object to
# be used elsewhere.
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: expression-reusing-verbose-snippets-
spec:
  arguments:
    parameters:
      - name: weather
        # The base64 string is this JSON: {"temps": [34, 27, 15, 57, 46]}
        value: '{"weekWeather": "eyJ0ZW1wcyI6IFszNCwgMjcsIDE1LCA1NywgNDZdfQo="}'
  entrypoint: main
  templates:
    - name: main
      inputs:
        parameters:
          - name: week-temps
            # The line being mapped over is verbose. Rather than repeat it, we use `map` to alias its output as #.
            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]
              }}
      script:
        env:
          - name: AVG
            value: "{{=jsonpath(inputs.parameters['week-temps'], '$.avg')}}"
          - name: MIN
            value: "{{=jsonpath(inputs.parameters['week-temps'], '$.min')}}"
          - name: MAX
            value: "{{=jsonpath(inputs.parameters['week-temps'], '$.max')}}"
        image: debian:9.4
        command: [bash]
        source: |
          echo "The week's average temperature was $AVG with a minimum of $MIN and a maximum of $MAX."