Rework some things into packages (#489)

logger.go

@@ -2,8 +2,12 @@ package nebula
 
 import (
 	"errors"
+	"fmt"
+	"strings"
+	"time"
 
 	"github.com/sirupsen/logrus"
+	"github.com/slackhq/nebula/config"
 )
 
 type ContextualError struct {
@@ -37,3 +41,38 @@ func (ce *ContextualError) Log(lr *logrus.Logger) {
 		lr.WithFields(ce.Fields).Error(ce.Context)
 	}
 }
+
+func configLogger(l *logrus.Logger, c *config.C) error {
+	// set up our logging level
+	logLevel, err := logrus.ParseLevel(strings.ToLower(c.GetString("logging.level", "info")))
+	if err != nil {
+		return fmt.Errorf("%s; possible levels: %s", err, logrus.AllLevels)
+	}
+	l.SetLevel(logLevel)
+
+	disableTimestamp := c.GetBool("logging.disable_timestamp", false)
+	timestampFormat := c.GetString("logging.timestamp_format", "")
+	fullTimestamp := (timestampFormat != "")
+	if timestampFormat == "" {
+		timestampFormat = time.RFC3339
+	}
+
+	logFormat := strings.ToLower(c.GetString("logging.format", "text"))
+	switch logFormat {
+	case "text":
+		l.Formatter = &logrus.TextFormatter{
+			TimestampFormat:  timestampFormat,
+			FullTimestamp:    fullTimestamp,
+			DisableTimestamp: disableTimestamp,
+		}
+	case "json":
+		l.Formatter = &logrus.JSONFormatter{
+			TimestampFormat:  timestampFormat,
+			DisableTimestamp: disableTimestamp,
+		}
+	default:
+		return fmt.Errorf("unknown log format `%s`. possible formats: %s", logFormat, []string{"text", "json"})
+	}
+
+	return nil
+}