Change trace duration to milliseconds

[TJ Holowaychuk]

I think nanoseconds is far too much granularity for the average use-case, I've never had a problem with millisecond resolution, but it's a breaking change.

[Mark Hemmings]

Yeah milliseconds make much more sense. I was thinking maybe to allow this without it being a breaking change, the duration unit could be on the Logger?

e.g.

type Logger struct {
	Handler   Handler
	Level     Level
	TraceUnit time.Duration
}

Then:

func (e *Entry) Stop(err *error) {
	duration := int64(time.Since(e.start) / e.Logger.TraceUnit)
	if err == nil || *err == nil {
		e.WithField("duration", duration).Info(e.Message)
	} else {
		e.WithField("duration", duration).WithError(*err).Error(e.Message)
	}
}

Can log in any duration you wish then (there will be occasional times where seconds is suitable) but still use nanoseconds by default.

[Jeffrey Faer]

Just poking through this repo. Looks like this was originally done in d1cd28b, and it still seems to be the case today:

https://github.com/apex/log/blob/v1.9.0/entry.go#L154
https://github.com/apex/log/blob/v1.9.0/entry.go#L53