Adding logger - guidance needed

[magicmark]

Hey! Thanks for the work on lemonade!

So I'm interested in adding a logger (#20) to work some other things out

I'm new to writing go code, so please excuse any errors - I also need a little guidance on how to get the logger instance into the rpc methods (since the server may set a different log level, it needs the right logger instance)
(EDIT: Looks like I can fix this with #21)

I also wanted to get your thoughts on how to do the logging - assuming we want log levels, it seems a 3rd party library would be better than the stdlib log package. I've done a some googling, and log15 seems reasonable - https://0value.com/about-Go-logging some comprehensive thoughts.

Cheers, lmk!

[pocke]

Thanks for your pull-request!

I also need a little guidance on how to get the logger instance into the rpc methods (since the server may set a different log level, it needs the right logger instance)

Does that mean using logger in Copy method for Clipboard or something? (e.g. https://github.com/pocke/lemonade/pull/23/files#diff-86c06ac664ab686be214d58c0a83b149R13 )
I think we have two way.
First, we can use global variable for logger. A scope for the variable is a bit wide(global, but unexported outside a package), but implementation is easy.

Second, we can extend the Clipboard struct. For example:

type Clipboard struct{
  logger log.Logger
}

clipboard := &Clipboard{
  logger: logger,
}
rpc.Regiser(clipboard)

In this way, the logger variable's scope is not wide. But I think the implementation is more difficult than the first way.

I also wanted to get your thoughts on how to do the logging - assuming we want log levels, it seems a 3rd party library would be better than the stdlib log package. I've done a some googling, and log15 seems reasonable - https://0value.com/about-Go-logging some comprehensive thoughts.

LGTM 👍

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Could you use goimports ? I use this command for formatting go code and manage import external packages.