Support logrus.Field logger in the logrus adapter

[sagikazarmark]

Logrus exposes an interface FieldLogger. It is usually better to hint against this interface, because the main logger instance returns a different type for loggers preannotated with structured context (namely *Entry). This way one can do this:

logger := kitlogrus.NewLogrusLogger(logrusLogger.With("component", "my_component"))

[ChrisHines]

The function still returns a go-kit log.Logger. It's the input type that has changed to accept the logrus.FieldLogger type.

The phrase "... to a Logrus logger" still seems accurate and perhaps more to the point. Ending with "... to a logrus.FieldLogger" would be more precise, but just repeating what the code says. I'm not a Logrus user, so I'm not sure which phrasing is more intuitive for that user base. Thoughts?

Suggested change

	// NewLogrusLogger returns a go-kit log.FieldLogger that sends log events to a Logrus logger.
	// NewLogrusLogger returns a go-kit log.Logger that sends log events to a Logrus logger.

[sagikazarmark]

Ah, good catch, it was kinda automatic change. 🙂

[ChrisHines]

Thanks for the contribution!

[sagikazarmark]

Thanks!