Refactor the volume ls command flagging process

[miles170]

See #1680

• Create a file in pkg/api/types/${cmd}_types.go, and define the CommandOption for this command
• Create some file in pkg/api/cmd/${cmd}, and move the command entry point in real into this package

Please let me know if I'm doing it incorrectly.

[Zheaoli]

This PR should be merged after #1774

[Zheaoli]

Since #1779 has been merged, I think this PR is ok to merge after resolve the code conflict

[miles170]

Shouldn't we add a prefix to the struct inside apparmor_types.go?
I renamed the LsCommandOptions to VolumeLsCommandOptions to avoid conflict.

[Zheaoli]

Shouldn't we add a prefix to the struct inside apparmor_types.go?

I renamed the LsCommandOptions to VolumeLsCommandOptions to avoid conflict.

Nice catch, I will add the prefix

[Zheaoli]

LGTM on CI green

[djdongjin]

nit: instead of storing in local variables everytime, you can do

options.Quiet, err := cmd.Flags().GetBool("quiet")
...

same for other options.

[djdongjin]

another style I recommand is first storing all flags in local variables and at the end, create the option struct

format, err := cmd.Flags().GetBool("format")
...
quiet,  err := cmd.Flags().GetBool("quiet")
...

option := types.VolumeLsCommandOptions{
    Format: format,
    Quiet: quiet,
}

[djdongjin]

seems this getVolumeStore is no longer needed as volume.Store should be preferred.

[djdongjin]

is this getVolumes func still being used somewhere? This func seems no longer necessary since it only read 4 flags from cmd and call another func.

If it's not common enough (e.g., used a lot by other commands as well), then we should remove this helper and instead prefer calling volume.Volumes directly.

[AkihiroSuda]

Thanks