option for JSON logging maybe?

[sigurdblueface]

It seems easy to implement and it also would be handy and useful for many people who use elasticsearch/loki etc

smth like this

func NewLogger(level uint32, format string) Logger {
	l := log.New()
	l.SetLevel(log.Level(level))
	switch format {
	case "json":
		logFormatter := &log.JSONFormatter {
			TimestampFormat: "2006-01-02 15:04:05",
		}
		l.Formatter = logFormatter
	default:
		logFormatter := &log.TextFormatter{
			FullTimestamp:   true,
			TimestampFormat: "2006-01-02 15:04:05",
		}
		l.Formatter = logFormatter
	}
	return &logger{l}
}

and just an additional field in Config struct

[tylertreat]

Yep, agreed. Better logging is something I've had in mind. Feel free to make a PR if you'd like.

[sigurdblueface]

well, I'm almost done with it here, but stuck on raftLogger's Write function:

[]byte to str conversion with JSON logger results here into lots of excessive escaped double quotes and newlines:

{"level":"error","msg":"raft: failed to make requestVote RPC: target=\"{Voter b b}\" error=\"nats: timeout\"\n","time":"2020-12-17 11:51:49"}
{"level":"error","msg":"raft: failed to make requestVote RPC: target=\"{Voter b b}\" error=\"nats: timeout\"\n","time":"2020-12-17 11:51:49"}
{"level":"warning","msg":"raft: Election timeout reached, restarting election\n","time":"2020-12-17 11:51:50"}
{"level":"info","msg":"raft: entering candidate state: node=\"Node at FdFmBT7CxmSNDOtAqXEtJe [Candidate]\" term=153\n","time":"2020-12-17 11:51:50"}
^C{"level":"info","msg":"Shutting down...","time":"2020-12-17 11:51:50"}
{"level":"error","msg":"raft: failed to make requestVote RPC: target=\"{Vot

And atm idk an elegant solution to this.

probably we should parse it to json fields with an additional function i.e:

{"level":"error","msg":"raft: failed to make requestVote RPC: target=\"{Voter b b}\" error=\"nats: timeout\"\n","time":"2020-12-17 11:51:49"}

should become:

{"level":"error","msg":"failed to make requestVote RPC","target":"Voter b b","error":"nats: timeout","time":"2020-12-17 11:51:49"}

what do you think?
any help or guidance would be much appreciated

[tylertreat]

Perhaps instead of overriding the LogOutput on the Raft config to use raftLogger, we should override the Logger. Hashicorp's logger has the ability to output as JSON (see here).