Support default refresh time for podman ps -w when no argument is provided

[dpateriya]

Feature request description

Currently, podman ps -w requires a mandatory argument, and fails with an error if none is given.
Proposing that if no argument is supplied, Podman should assume a default watch time (e.g., 1 or 2 seconds) instead of erroring out.

Motivation:

• Improves user experience by allowing quick usage without needing to explicitly specify a timeout.

• Aligns with behavior seen in other CLI tools where defaults are assumed for usability.

• Provides backward compatibility, where users specifying a timeout explicitly are unaffected.

Current Behavior:

$ podman ps -w
Error: flag needs an argument: 'w' in -w
See 'podman ps --help'

Benefits:

• Better UX for ad-hoc use
• Simplifies scripting
• Reduces potential errors/mistakes during quick commands

Suggest potential solution

$ podman ps -w
(watch every 1-2 seconds, then show running containers)

Additional context

Podman Version: 5.2.2

OS: RHEL 9

Related flags/commands: podman ps -w

[dpateriya]

/label feature

[openshift-ci]

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In response to this:

/label feature

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[mheon]

Looks like optional value definitions are possible in Cobra, but this could be a bit messy regardless

[ninja-quokka]

From a UX point of view I would expect podman ps -w to watch with a timeout of 0 by default.

Then if a value like 10 is passed it would only watch for 10 seconds.

Edit: Please disregard.

[Luap99]

What would a default timeout of 0 mean then? Busy spinning ps would be a bad idea and a user wouldn't be able to read the output anyway if it updates so quickly. I think it should likely be at least 2s if we set a default.

Looks like optional value definitions are possible in Cobra, but this could be a bit messy regardless

Yes it is possible with NoOptDefVal, though we generally don't use it.

Personally I don't understand why we have such option to begin with, it doesn't offer anything over watch podman ps IMO. But given it already exist adding a default time wouldn't change much.

[ninja-quokka]

What would a default timeout of 0 mean then? Busy spinning ps would be a bad idea and a user wouldn't be able to read the output anyway if it updates so quickly. I think it should likely be at least 2s if we set a default.

Apologies, I misunderstood the the --watch arg.

To clarify I agree the --watch feature doesn't add much but it's not an uncommon feature for CLIs to have.

I agree with the reporter that a default of 2s would be good UX for the --watch argument.

[ninja-quokka]

I pushed an example PR: #26012 to check the apatite for having such a default value.

[ninja-quokka]

Due to limitations with the cobra cli library this would cause a breaking change. We will consider this again for 6.0 release.

[github-actions]

A friendly reminder that this issue had no activity for 30 days.