Remove cmd package

[asim]

Looking at removing the cmd package. I think flag and env var parsing was initially quite useful when the surface area of go-micro was small. Over time that's gotten broader and more complex to manage. Ultimately if go-micro is pluggable, then either the cmd package needs to be totally rewritten or removed entirely.

[asim]

The protobuf code generator has moved to https://github.com/go-micro/generator

[Davincible]

Could you elaborate a bit more? Personally I still configure my go-micro services completely with env vars as its most versatile and it's easier to change a single .env file compared to cmd args in a k8s deployment.

What would need to be rewritten and why?

[asim]

The cmd package was mostly a hack. It's not a pluggable one. It's not something where you can pick and choose your parsers. It would make more sense as a config package with configurable functions to execute the parsing. Right now it's a very hard coded fixed thing. I think it would make more sense as a separate utility or to just be in the util dir.

[vtolstov]

If you prefer to specify config stuff in config struct tags you can use something like this (not fully compatible with go-micro)
https://github.com/unistack-org/micro-config-flag/blob/v3/flag_test.go#L27

[asim]

I think it makes sense. And to maybe even rewrite the config package to enable very easy parsing and access to stuff like this for env and flags to do the same as what was occurring before but be even more flexible so that the user can essentially parse all the things they need. In micro we rewrote the config interface for that.

https://github.com/micro/micro/blob/master/service/config/config.go#L26

[Davincible]

@asim just to double check, you were talking about the package that is now at util/cmd/cmd.go ?

[asim]

Yea, it's convenient for initialisation but not a mandatory feature

[keepstep]

it is a problem that cmd's default option will overwrite options that code in srv.Init,
so i must call srv.Init again if want option effect

// Create service  
srv := micro.NewService()  
// cmd will overwrite some option like "micro.RegisterInterval micro.RegisterTTL"  
srv.Init(  
    micro.RegisterInterval(time.Second * 5), 
    micro.RegisterTTL(time.Second * 10),  
)
// must init again   
srv.Init(  
   micro.RegisterInterval(time.Second * 5),  
   micro.RegisterTTL(time.Second * 10),  
)