pkg/log: create wrapper around logrus

pkg/log/log.go

@@ -0,0 +1,124 @@
+// Package log adds a thin wrapper around logrus to improve non-debug logging
+// performance.
+package log
+
+import (
+	"fmt"
+
+	"github.com/Sirupsen/logrus"
+)
+
+var (
+	l     = logrus.New()
+	debug = false
+)
+
+// SetDebug controls debug logging.
+func SetDebug(to bool) {
+	debug = to
+}
+
+// SetFormatter sets the formatter.
+func SetFormatter(to logrus.Formatter) {
+	l.Formatter = to
+}
+
+// Fields is a map of logging fields.
+type Fields map[string]interface{}
+
+// LogFields implements Fielder for Fields.
+func (f Fields) LogFields() Fields {
+	return f
+}
+
+// A Fielder provides Fields via the LogFields method.
+type Fielder interface {
+	LogFields() Fields
+}
+
+// err is a wrapper around an error.
+type err struct {
+	e error
+}
+
+// LogFields provides Fields for logging.
+func (e err) LogFields() Fields {
+	return Fields{"error": e.e.Error()}
+}
+
+// Err is a wrapper around errors that implements Fielder.
+func Err(e error) Fielder {
+	return err{e}
+}
+
+// mergeFielders merges the Fields of multiple Fielders.
+// Fields from the first Fielder will be used unchanged, Fields from subsequent
+// Fielders will be prefixed with "%d.", starting from 1.
+//
+// must be called with len(fielders) > 0
+func mergeFielders(fielders ...Fielder) logrus.Fields {
+	if fielders[0] == nil {
+		return nil
+	}
+
+	fields := fielders[0].LogFields()
+	for i := 1; i < len(fielders); i++ {
+		if fielders[i] == nil {
+			continue
+		}
+		prefix := fmt.Sprint(i, ".")
+		ff := fielders[i].LogFields()
+		for k, v := range ff {
+			fields[prefix+k] = v
+		}
+	}
+
+	return logrus.Fields(fields)
+}
+
+// Debug logs at the debug level if debug logging is enabled.
+func Debug(v interface{}, fielders ...Fielder) {
+	if debug {
+		if len(fielders) != 0 {
+			l.WithFields(mergeFielders(fielders...)).Debug(v)
+		} else {
+			l.Debug(v)
+		}
+	}
+}
+
+// Info logs at the info level.
+func Info(v interface{}, fielders ...Fielder) {
+	if len(fielders) != 0 {
+		l.WithFields(mergeFielders(fielders...)).Info(v)
+	} else {
+		l.Info(v)
+	}
+}
+
+// Warn logs at the warning level.
+func Warn(v interface{}, fielders ...Fielder) {
+	if len(fielders) != 0 {
+		l.WithFields(mergeFielders(fielders...)).Warn(v)
+	} else {
+		l.Warn(v)
+	}
+}
+
+// Error logs at the error level.
+func Error(v interface{}, fielders ...Fielder) {
+	if len(fielders) != 0 {
+		l.WithFields(mergeFielders(fielders...)).Error(v)
+	} else {
+		l.Error(v)
+	}
+}
+
+// Fatal logs at the fatal level and exits with a status code != 0.
+func Fatal(v interface{}, fielders ...Fielder) {
+	if len(fielders) != 0 {
+		l.WithFields(mergeFielders(fielders...)).Fatal(v)
+	} else {
+		l.Fatal(v)
+	}
+}

pkg/prometheus/server.go

@@ -6,7 +6,7 @@ import (
 	"context"
 	"net/http"
 
-	log "github.com/Sirupsen/logrus"
+	"github.com/chihaya/chihaya/pkg/log"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -42,7 +42,7 @@ func NewServer(addr string) *Server {
 
 	go func() {
 		if err := s.srv.ListenAndServe(); err != http.ErrServerClosed {
-			log.Fatal("failed while serving prometheus: " + err.Error())
+			log.Fatal("failed while serving prometheus", log.Err(err))
 		}
 	}()