[bug] Cannot complete commands with kubectl kc

[nekomeowww]

Describe the bug

Cannot complete commands with kubectl kc.

How to reproduce issues

Cannot complete commands with kubectl kc

Steps to reproduce the behavior:

1. Install kubecm with kubectl krew install kc
2. Verify whether auto completion enabled or appended with echo "autoload -U compinit; compinit" >> ~/.zshrc
3. Configured completion with kubectl kc completion zsh > "${fpath[1]}/_kubecm"
4. Verify that the kubectl kc list lists all the contexts, got the following outputs:

❯ kubectl kc list
+------------+-----------------------------------+-----------------------------------+-----------------------------------+-----------------------------------+--------------+
|   CURRENT  |                NAME               |              CLUSTER              |                USER               |               SERVER              |   Namespace  |
+============+===================================+===================================+===================================+===================================+==============+
|            |              minikube             |              minikube             |              minikube             |      https://127.0.0.1:32769      |    default   |
+------------+-----------------------------------+-----------------------------------+-----------------------------------+-----------------------------------+--------------+

Cluster check succeeded!
Kubernetes version v1.26.7
Kubernetes master is running at https://127.0.0.1:32769
[Summary] Namespace: 9 Node: 1 Pod: 28

5. Input kubectl kc switch and then tab, got the following outputs:

❯ kubectl kc switch Applications/
Applications/                 Documents/

Expected behavior

Should prompt sub-commands and its all descriptions.

Desktop (please complete the following information):

• OS: macOS
• Version: 0.25.0
• GoOs: darwin
• GoArch: arm64

[sunny0826]

@nekomeowww Thanks for the feedback. This is a known issue, in fact, auto-completion does not work when kubecm is run as a kubectl plugin, this is due to the kubectl mechanism, completion only works when kubecm is run as a standalone CLI.

[nekomeowww]

Oh, ok. Thanks for replying!

I never heard of this limitation, I might have to take a look at kubectl cli and its community to seek out a solution or plan.

Is that ok if I create a documentation update Pull Request and state out the limitations of kubectl and the installation through kubectl krew?

[sunny0826]

Absolutely! Thank you for your contribution!

[nekomeowww]

FYI, it looks like the completion is currently supported for plugins of kubectl since kubernetes/kubernetes#105867 was merged.

However I haven't figure out how to use the documented way of this Pull Request to make the completion possible for kubectl kc. I will keep you updated whether I succeed or failed.

[sunny0826]

Thank you very much! Looks like I'm out of date.

[marckhouzam]

Since this plugin uses Cobra, making shell completion work is very easy.
You need to provide an executable file called kubectl_complete-kc which can be found on $PATH.
Below shows how to generate that file with the proper content.
Kubectl will call that file to obtain the shell completion results.

# Generate the required file
cat <<EOF >kubectl_complete-kc
#!/usr/bin/env sh

# Call the __complete command passing it all arguments
kubectl kc __complete "\$@"
EOF

# Make the file executable
chmod u+x kubectl_complete-kc

Now put the above file somewhere on your $PATH

@sunny0826 You could provide this file in your repo and provide instructions telling users to install it on $PATH.
Note that krew does not yet support installing this file. Ref: kubernetes-sigs/krew#812

@nekomeowww Until this is available you can use this project to automatically make such completions work for any kubectl plugin that uses the https://github.com/spf13/cobra project

I just used it with kc and it works great

[sunny0826]

@marckhouzam Thank you so much !

[nekomeowww]

Thanks for replying and participating this issue! @marckhouzam

@sunny0826 You could provide this file in your repo and provide instructions telling users to install it on $PATH.
Note that krew does not yet support installing this file. Ref: kubernetes-sigs/krew#812

@nekomeowww Until this is available you can use this project to automatically make such completions work for any kubectl plugin that uses the https://github.com/spf13/cobra project

I've tried either your plugin kubectl-plugin_completion or the direct executable shell for _complete, however I cannot get the completion for kubecm to work properly.

For the manual, and direct shell, the completion file contains the following content:

#!/usr/bin/env zsh

# Call the __complete command passing it all arguments
kubectl kc __complete "\$@"

However, it would produce the following error when trying to use TAB to request the completion:

❯ kubectl kc (eval):1: command not found: _kubectl
(eval):1: command not found: _kubectl

If I try to execute the so do "proxy" completion shell directly, I get the prompt to say the completion ended:

❯ kubectl_complete-kc
:4
Completion ended with directive: ShellCompDirectiveNoFileComp

I just used it with kc and it works great

So how does your kubectl kc works?

[marckhouzam]

I've tried either your plugin kubectl-plugin_completion or the direct executable shell for _complete, however I cannot get the completion for kubecm to work properly.

For the manual, and direct shell, the completion file contains the following content:

#!/usr/bin/env zsh

# Call the __complete command passing it all arguments
kubectl kc __complete "\$@"

There should not be a \ before the $ sign in the script. The \ was in my output because I was using cat

However, it would produce the following error when trying to use TAB to request the completion:

❯ kubectl kc (eval):1: command not found: _kubectl
(eval):1: command not found: _kubectl

Not sure about the above. Let's see if the other comments get rid of it.

If I try to execute the so do "proxy" completion shell directly, I get the prompt to say the completion ended:

❯ kubectl_complete-kc
:4
Completion ended with directive: ShellCompDirectiveNoFileComp

Try kubectl_complete-kc ''

Assuming you have shell completion working for kubectl this is what I did.
Make sure that $HOME/.kubectl-plugin-completion/ is on your PATH.

$ echo $SHELL
/bin/zsh

$ kubectl version --client
Client Version: v1.28.3
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3

$ kubectl krew install kc
Updated the local copy of plugin index.
Installing plugin: kc
W1023 10:12:49.612027    2698 install.go:160] Skipping plugin "kc", it is already installed

$ kubectl plugin-completion generate
[...]
# The above should generate the following file.
# Note that it is a little fancier than what I recommended in the previous
# command as it tries to complete the --namespace flag value as well
# but you don't really need that.
$ cat ~/.kubectl-plugin-completion/kubectl_complete-kc
#!/bin/bash
out=$(kubectl kc __complete "$@")

# If, once we remove the directive, there are completions, let's print them
if [ -n "${out%%:*}" ]; then
   printf "%s\n" "${out[@]}"
elif [[ ${@: -2:1} = "-n" ]] || [[ ${@: -2:1} = "--namespace" ]]; then
   # If there are no completions we provide completions if the previous argument is -n/--namespace.
   # This case is pretty common but normally requires the plugin to have added support for it.
   kubectl get namespaces --output go-template='{{ range .items }}{{ .metadata.name }}{{"\n"}}{{ end }}'
   # Turn off file completion
   echo :4
fi

$ kubectl <TAB>
annotate           -- Update the annotations on a resource
api-resources      -- Print the supported API resources on the server
api-versions       -- Print the supported API versions on the server, in the form of "group/version"
[...]
kc                 -- The command kc is a plugin installed by the user
[...]


$ kubectl kc <TAB>
add         -- Add KubeConfig to $HOME/.kube/config
alias       -- Generate alias for all contexts
clear       -- Clear lapsed context, cluster and user
cloud       -- Manage kubeconfig from cloud
completion  -- Generate completion script
create      -- Create new KubeConfig(experiment)
delete      -- Delete the specified context from the kubeconfig
export      -- Export the specified context from the kubeconfig
help        -- Help about any command
list        -- List KubeConfig
merge       -- Merge multiple kubeconfig files into one
namespace   -- Switch or change namespace interactively
rename      -- Rename the contexts of kubeconfig
switch      -- Switch Kube Context interactively
version     -- Print version info

[nekomeowww]

There should not be a \ before the $ sign in the script. The \ was in my output because I was using cat

Try kubectl_complete-kc ''

Thanks for pointing out these incorrect setup for me. I didn't find out these mistakes before.

And I can get

kubectl_complete-kc ''

working right now.

However, both kubectl plugin-completion generate generated and hand written completion helper failed to be executed when used with kubectl kc, it still prompts

❯ kubectl kc (eval):1: command not found: _kubectl
(eval):1: command not found: _kubectl

My kubectl version results as

❯ kubectl version
Client Version: v1.28.3
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: v1.27.3

which should be compatible with the feature you added.

And indeed my completion for kubectl somehow be broken at some point of time. Let me investigate it and update when I find out the cause of it.

[nekomeowww]

Ok I've located the root cause. Such issue consists two major cause:

1. Auto completion script for zsh (which is source <(kubectl completion zsh)) must be incorrectly modified by myself when I playing around krew, kubectl plugin-completion generate and messing around with my .zshrc, it miss-commented out at some point.
2. When I remove the comment to my kubectl, completion plugins is still not working, with which kubectl I found out that my kubectl somehow pointed to /usr/local/bin/kubectl, while zsh of kubectl points to 1.28.3, bash didn't include the required $PATH for homebrew installation, it still uses the old v1.22.5 build, must be installed by the other applications or scripts.

I have gathered my needed blocks to test and contribute to kubecm, I will submit a Pull Request ASAP later this day or tomorrow.

Again, thanks for debugging and providing me such details @marckhouzam , much appreciated.