Using go-kit logger api missing methods - go

Question

I want to use the logger from go kit repository and I saw that
that the author provided also logrus API/factory , while trying to test it with some common API functionality of logrus like ,withFields and error / info / panic etc
I couldn't use them only log
Any idea how can I add the missing log functionality ?
logrus.WithField API.
this is what I miss
log.WithFields(log.Fields{
"animal": "walrus",
}).Info("A walrus appears")
and also the info / error / debug etc
This is what I've tried
package main
import (
log "github.com/go-kit/kit/log/logrus"
"github.com/sirupsen/logrus"
)
func main() {
logrusLogger := logrus.New()
logrusLogger.Formatter = &logrus.JSONFormatter{TimestampFormat: "02-01-2006 15:04:05"}
logger := log.NewLogrusLogger(logrusLogger)
logger.Log("hello", "world”) //working
logger.WithFields( //doesnt work
logger.Info( //doesnt work
}
The logger is type logrus but I cannot use withFields OR info/error/debug etc, any idea what am I missing here?
as the log kit create some factory is there a way to use the logrus api ?

Answer 1

It's because log.NewLogrusLogger() creates the unexported logruslogger which has only one method Log (satisfying the log.Logger interface). It doesn't support the other methods from logrus itself.
This Log method can take arguments in key value pairs and put them in logrus.Fields while logging. So if you do Log("hello", "world"), it would set hello field's value to world. But this wouldn't work for level or other features.
However, since logrus.FieldLogger is embedded in the implementation of the logruslogger, we can assert our logger to behave like logrus.FieldLogger and then do this:
package main
import (
log "github.com/go-kit/kit/log/logrus"
"github.com/sirupsen/logrus"
)
func main() {
logrusLogger := logrus.New()
logrusLogger.Formatter = &logrus.JSONFormatter{TimestampFormat: "02-01-2006 15:04:05"}
logger := log.NewLogrusLogger(logrusLogger).(logrus.FieldLogger)
logger.Error("Hello")
logger.Warn("Warning you")
logger.WithField("good", "bad").Infoln("is it good or bad?")
}
I hope this helps. But since they only exposed the Log method, there might be conscious design decisions behind those. You may keep using just Log or if you want more flexibility, I would suggest setting up your own logger (using logrus) instead of what I just did above. That would be a cleaner approach IMO.