[Metricbeat] Rename Logger method to Log

[ruflin]

Based on the comment #11106 (comment) the Logger method is renamed to Log. It turned out this was already almost a convention which we used across the metricsets. This meant the Log variable and Log() method conflicted and required an update in the metricsets that had a Log variable.

No functionality was changed in this PR.

[ruflin]

Put to in progress again as we should discuss again if Log or Logger is better here.

[andrewkroh]

LGTM 😄

[andrewkroh]

The godoc here will need updated too.

[ruflin]

Seems like you are better then hound :-)

[urso]

+1 on shorter names

[fearful-symmetry]

+1, Seems good.

[cachedout]

+1 but this does raise the question of whether it would be good to document these sorts of conventions in the developer documentation.

[ruflin]

@cachedout Yes, @fearful-symmetry has some ideas plans around this.

[sayden]

My 2 cents: This breaks common naming conventions and I don't think that by documenting it, it will help to understand code better and faster, let me explain:

• Log() object [verb/action] method or function is expected to return a log line of text (object), based on some state.
• Log(arg) [verb/action] is expected to log arg at the default level (like t.Log in testing package). If you add Log(arg) object is usually expected that object is going to be an object or an error.
• Log() [verb/action] is expected to log something at the default level based on some state: accumulated logs, for example, based on different log strategies, not just to print to stdout but it might be to Logstash and the destination and complexity is hidden / abstracted from the caller.
• Log [object] variable is expected to contain a piece of text, a log.
• Logger interface is expected to contain the methods needed to implement a logger.
• Logger() object [noun] method is expected to return an interface with an initialized logger which implements Logger interface, based on some state or not. Function call is expected to initialize and return a new Logger which also implements the same interface.
• Logger(arg) object [noun] method or function is expected to return a Logger initialized with something based on arg.
• Logger [noun] variable, is expected to container a implementor of Logger interface.
• NewLogger() [action-noun] is expected to initialize a new Logger. NewLogger() object is expected to initialize a new Logger and return it, but not store it.

As you can see, actions/verbs are usually function or type methods while nouns are usually types. This methodology is actually quite old (I think from the times of UML) but it's still valid today and makes a lot of sense.

+1 on shorter names if they don't affect code comprehension for new arrivals or community contributors. All in all that's why we all have autocomplete in our IDE 😉

[ruflin]

Closing this PR as it will not make a big difference from my point of view. If someone wants to take over, please go for it :-)