fix tail library logs to use our own log format (#579)

* fix tail library logs to use our own log format

* PR Feedbacks

pkg/promtail/targets/tailer.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/grafana/loki/pkg/promtail/api"
 	"github.com/grafana/loki/pkg/promtail/positions"
+	"github.com/grafana/loki/pkg/util"
 )
 
 type tailer struct {
@@ -54,6 +55,7 @@ func newTailer(logger log.Logger, handler api.EntryHandler, positions *positions
 		return nil, err
 	}
 
+	logger = log.With(logger, "component", "tailer")
 	tailer := &tailer{
 		logger:    logger,
 		handler:   api.AddLabelsMiddleware(model.LabelSet{FilenameLabel: model.LabelValue(path)}).Wrap(handler),
@@ -64,6 +66,8 @@ func newTailer(logger log.Logger, handler api.EntryHandler, positions *positions
 		quit: make(chan struct{}),
 		done: make(chan struct{}),
 	}
+	tail.Logger = util.NewLogAdapater(logger)
+
 	go tailer.run()
 	filesActive.Add(1.)
 	return tailer, nil

pkg/util/log.go

@@ -0,0 +1,74 @@
+package util
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/log/level"
+)
+
+type LogAdapater struct {
+	log.Logger
+}
+
+func NewLogAdapater(l log.Logger) LogAdapater {
+	return LogAdapater{
+		Logger: l,
+	}
+}
+
+// Fatal implements tail.logger
+func (l LogAdapater) Fatal(v ...interface{}) {
+	level.Error(l).Log("msg", fmt.Sprint(v...))
+	os.Exit(1)
+}
+
+// Fatalf implements tail.logger
+func (l LogAdapater) Fatalf(format string, v ...interface{}) {
+	level.Error(l).Log("msg", fmt.Sprintf(strings.TrimSuffix(format, "\n"), v...))
+	os.Exit(1)
+}
+
+// Fatalln implements tail.logger
+func (l LogAdapater) Fatalln(v ...interface{}) {
+	level.Error(l).Log("msg", fmt.Sprint(v...))
+	os.Exit(1)
+}
+
+// Panic implements tail.logger
+func (l LogAdapater) Panic(v ...interface{}) {
+	s := fmt.Sprint(v...)
+	level.Error(l).Log("msg", s)
+	panic(s)
+}
+
+// Panicf implements tail.logger
+func (l LogAdapater) Panicf(format string, v ...interface{}) {
+	s := fmt.Sprintf(strings.TrimSuffix(format, "\n"), v...)
+	level.Error(l).Log("msg", s)
+	panic(s)
+}
+
+// Panicln implements tail.logger
+func (l LogAdapater) Panicln(v ...interface{}) {
+	s := fmt.Sprint(v...)
+	level.Error(l).Log("msg", s)
+	panic(s)
+}
+
+// Print implements tail.logger
+func (l LogAdapater) Print(v ...interface{}) {
+	level.Info(l).Log("msg", fmt.Sprint(v...))
+}
+
+// Printf implements tail.logger
+func (l LogAdapater) Printf(format string, v ...interface{}) {
+	level.Info(l).Log("msg", fmt.Sprintf(strings.TrimSuffix(format, "\n"), v...))
+}
+
+// Println implements tail.logger
+func (l LogAdapater) Println(v ...interface{}) {
+	level.Info(l).Log("msg", fmt.Sprint(v...))
+}