Weird argument arrangement when using script template

[ivancili]

Summary

I wanted to add a template that is activated on a workflow exit (the onExit field) with a purpose of notifying the user about the workflow status. I decided to use a template of type script, like this:

name: "workflow-status-test"
script: 
 image: "python:3.6-alpine"
 command:
  - python3
 args:
  - "{{workflow.status}}"
 source: "import sys; import my_notify_func; my_notify_func(sys.argv[1])"

This failed. After inspecting the pod, I saw that Argo passed the arguments to the python container in the following way Succeeded /argo/staging/script, I would expect it to do it like this /argo/staging/script Succeeded.

Later I noticed in one of your examples in git repo that I could embed a template directly in the source field. But this wasn't documented anywhere (at least I didnt see it). So, this solves my issue:

name: "workflow-status-test"
script: 
 image: "python:3.6-alpine"
 command:
  - python3
 source: "import my_notify_func; my_notify_func('{{workflow.status}}')"

The order in which the arguments are passed is unintuitive and I don't see a case where this particular order would be useful. My suggestion is to change the order (so first goes the script path, and then the user args) or put a notice/disclaimer in the docs. Also, you could provide an example for using templates here, or document it.

Use Cases

When would you use this?

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[alexec]

Why not do this:

name: "workflow-status-test"
script: 
 image: "python:3.6-alpine"
 command:
  - python3
 source: |
   import sys; import my_notify_func; my_notify_func("{{workflow.status}}")

[ivancili]

@alexec Yes, as I said, that works just fine and is more than enough for my use case.

All I'm saying is that this behavior is unexpected/unintuitive. As soon as someone tries to use args field in a script template, they will definitely encounter the same problem. Because no one would expect args to be passed directly to the command, instead of passing them to the script. It's not that big of a deal really, I would probably just document it in "Field reference" page and provide an example with templates under "Examples".

[alexec]

Got it. Would you like to submit a PR to fix?

[ivancili]

@alexec Sure