feat(logging): log timestamps in RFC3339Milli

- Changes the timestamp format to human-readable RFC3339.
- Increases the precision to millisecond from second.

Author: alextes

common/logging.go

@@ -6,15 +6,22 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// RFC3339Milli is a RFC3339 timestamp format restricted to millisecond precision.
+// No standard format is provided, so we create our own.
+const RFC3339Milli = "2006-01-02T15:04:05.000Z07:00"
+
 func LogSetup(json bool, logLevel string) *logrus.Entry {
 	log := logrus.NewEntry(logrus.New())
 	log.Logger.SetOutput(os.Stdout)
 
 	if json {
-		log.Logger.SetFormatter(&logrus.JSONFormatter{})
+		log.Logger.SetFormatter(&logrus.JSONFormatter{
+			TimestampFormat: RFC3339Milli,
+		})
 	} else {
 		log.Logger.SetFormatter(&logrus.TextFormatter{
-			FullTimestamp: true,
+			TimestampFormat: RFC3339Milli,
+			FullTimestamp:   true,
 		})
 	}