[1.12] plugin commands with dashes cannot be invoked with their original names

[ahmetb]

Is this a BUG REPORT or FEATURE REQUEST? (choose one): BUG REPORT
Kubernetes version (use kubectl version): 1.12.0-beta.2

What happened:

There are already plugins named with dashes (-) in the plugin name, such as:

• open-svc
• ca-cert
• rm-standalone-pods

in the krew package manager. There are also many plugins outside krew, such as:

• decode-secret
• rbac-lookup
• ...

kubectl 1.12 splits the names of these plugins into separate subcommands, such as:

previously called	now called as
kubectl plugin open-svc	kubectl open svc [...]
kubectl plugin rm-standalone-pod	kubectl rm standalone pod [...]

What you expected to happen:

This new behavior is quite unexpected for me. This makes it:

1. impossible to write plugins with dashes in the name

   For example, if I write a plugin named port-forward-better, my users have to invoke it as kubectl port forward better (not desirable) as opposed to kubectl port-forward-better.

2. Undesired categorization of plugins that share the same prefix:

   For example, if I'm writing a plugin named rm-standalone-pods installing a plugin with another rm- prefix (such as rm-completed-jobs). They will be (someday) grouped under kubectl rm despite they're different plugins.

I Expected: if a plugin named kubectl-delete-all exists, I should be able to call it kubectl delete-all. Being able to call it as kubectl delete all may still be ok as the artifact of the feature, but it should not prevent kubectl delete-all invocation.

I am sorry I wasn't there to review the design but I think design won't work for the broader plugin ecosystem.

/cc @soltysh
/cc @lbb

[seans3]

/kind bug
/sig cli
/area kubectl
/priority P2
/assign @juanvallejo

[juanvallejo]

Hey @ahmetb thanks for pointing this out.
Under the new design, you can use underscores in your plugin executable's name to allow for plugin command names with dashes:

$ cat /usr/local/bin/kubectl-dash_test
#!/bin/bash

echo "I am a plugin with a dash in my name"

$ kubectl dash-test
I am a plugin with a dash in my name

I have a PR updating the website's plugin documentation here and will make sure to specifically mention this part of the design on there.

Thanks

[ahmetb]

@juanvallejo That sounds like good news! It's not a great hack but it seems like it can do the trick. I'll close this once I verify.

[ahmetb]

/assign

[juanvallejo]

@ahmetb

That sounds like good news! It's not a great hack but it seems like it can do the trick. I'll close this once I verify.

Thanks. To clarify, this does not prevent underscores from being used as part of a command's name, rather it means that plugin commands with underscores can be invoked either with an underscore or a dash:

$ kubectl dash-test
I am a plugin with a dash in my name

$ kubectl dash_test
I am a plugin with a dash in my name

[ahmetb]

@juanvallejo Yes, I see now. I think this gives us enough to refactor existing krew plugins to work. Thanks.