Using Expr Lang to pass Spring Batch JobParameters to .spec.templates[*].container.args

[kworkbee]

Hello, I'm configuring a WorkflowTemplate that delivers JobParameters as arguments to Spring Batch application

kind: WorkflowTemplate
spec:
  templates:
    - container:
        name: ''
        image: '{{inputs.parameters.image}}'
        args:
          - '--job.name={{inputs.parameters.jobname}}' # Will be placed by Configuration Property `spring.batch.job.name=${}`
          - '{{inputs.parameters.additionalArgs}}' # **A problematic part**
        env:
          - name: SPRING_PROFILES_ACTIVE
            value: '{{inputs.parameters.profile}}'
          - name: JAVA_TOOL_OPTIONS
            value: '{{inputs.parameters.javaOption}}'
          - name: TZ
            value: '{{inputs.parameters.timezone}}'

JobParameters as below

startDate=2024-12-31,java.lang.String endDate=2025-12-31,java.lang.String

I want to bind to individual items in args when there are multiple items. (by splitting inputs.parameters.additionalArgs by whitespace) If it goes into a single item, there is a problem that only the first item is recognized by the actual application based on whitespace, so it does not work normally.

I need your help!

[MasonM]

Parameters can only be passed as strings. You could use a shell script to handle splitting the items, e.g.:

spec:
  arguments:
    parameters:
      - name: custom_arguments
        default: "--batch=1 --ckpt=another_value"
  templates:
    - name: main
      container:
        command: ["sh", "-c"]
        args: ["main.py {{workflow.parameters.custom_arguments}}"]

[kworkbee]

I can't solve it directly, but I have to deal with it indirectly, right? Thank you for your answer.

[jswxstw]

Maybe, you can try using expr to generate args.

[kworkbee]

I don't think this is going to be splitted into individual elements of the args array like using Go Template on the Helm chart.

[jswxstw]

If the number of elements in additionalArgs is fixed, you can directly use split to achieve this. Here is an example:

metadata:
  name: expr-demo
spec:
  arguments:
    parameters:
      - name: shell
        value: "echo hello"
  entrypoint: argosay
  templates:
    - name: argosay
      inputs:
        parameters:
          - name: shell
            value: "{{workflow.parameters.shell}}"
      container:
        name: main
        image: argoproj/argosay:v2
        command:
          - /argosay
        args:
          - "{{=split(inputs.parameters.shell,' ')[0]}}"
          - "{{=split(inputs.parameters.shell,' ')[1]}}"

[kworkbee]

The number of arguments cannot be predicted currently (It depends on the job.)

[jswxstw]

Then it seems that there is no solution using only Argo templating.