Display timestamp in log and allow logging to file

src/metrics-alerting/log.go

+package main
+
+import (
+	"os"
+
+	"github.com/sirupsen/logrus"
+)
+
+type utcFormatter struct {
+	logrus.Formatter
+}
+
+func (f utcFormatter) Format(entry *logrus.Entry) ([]byte, error) {
+	entry.Time = entry.Time.UTC()
+	return f.Formatter.Format(entry)
+}
+
+func logConfig() error {
+	var disableColors = false
+
+	if len(*logFile) > 0 {
+		f, err := os.OpenFile(*logFile, os.O_WRONLY|os.O_CREATE, 0755)
+		if err != nil {
+			return err
+		}
+		logrus.SetOutput(f)
+
+		disableColors = true
+	}
+
+	logrus.SetFormatter(&utcFormatter{
+		&logrus.TextFormatter{
+			TimestampFormat:  "2006-01-02T15:04:05.000000000Z07:00",
+			FullTimestamp:    true,
+			DisableColors:    disableColors,
+			DisableTimestamp: false,
+			DisableSorting:   false,
+		},
+	})
+
+	return nil
+}

src/metrics-alerting/main.go

 
 var (
 	configPath = flag.String("config", "config.yaml", "The path to the config file. For more information, see the config file in this repository.")
+	logFile    = flag.String("log-file", "", "The path to the file logs should be directed to. If empty or not provided, logs will be output through standard output.")
 )
 
 func main() {
 	flag.Parse()
 
+	if err := logConfig(); err != nil {
+		logrus.Warn(err)
+	}
+
 	cfg := config.Config{}
 	if err := cfg.Load(*configPath); err != nil {
 		logrus.Panic(err)