Regroup the command implementations in respective sub-packages

[navidshaikh]

Presently, all the command implementations reside under pkg/kn/commands/, we should re-group the implementations based on command-group.

for eg:

pkg/kn/commands/service/ <-- implementing all the sub-commands under kn service
pkg/kn/commands/revision/
pkg/kn/commands/build/
pkg/kn/commands/

and so on..

[maximilien]

So I took at pass at this when I was doing the plugin command. It's doable but requires the following changes:

1. move some types from root.go to a common package to avoid import cycles, e.g., this common package for one of my plugin branches

2. sweeping change to each command to use the common package above, e.g., this plugins example

Bottom line is that it's not hard to do just requires agreement and one swoop change.

If you guys want this before milestone 1 I could do this this week, while you all asleep in Europe. I'll add this to the agenda tomorrow as a low priority issue.

/cc @sixolet @cppforlife

[navidshaikh]

IMO, we should aim this as first thing after v0.1.

[rhuss]

@maximilien Is this something you are already on ? I'm asking while I'm working on #14 I also want to split up and separate the commands better (as I want to use some some package scoped vars which shouldn't 'pollute' whole "commands").

I agree that we need a "common" package which should hold the shared code, e.g. KnParams. I also believe that KnParams should be an interface defined in common and an implementation in the root "commands" package.

As I'm on it as well, I would be happy also to take over this task if you don't have a chance to come to is soonish. (there are some other subtle things like how to register subcommands and also the human-readable printers now reference commands directly).

In any case, we should tackle this issue very soon.

[maximilien]

OK as per discussion today. Let me submit something today. I am sure you guys will have lots of feedback. More soon.

[maximilien]

Done in #145