Merge pull request #42 from nathanejohnson/feature/modular_logging

Remove hard dependency on logrus for logging

Author: thrawn01

go.mod

@@ -4,6 +4,7 @@ require (
 	github.com/golang/protobuf v1.3.1
 	github.com/segmentio/fasthash v1.0.3
 	github.com/sirupsen/logrus v1.6.0
+	golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a // indirect
 )
 
 go 1.15

go.sum

@@ -6,11 +6,13 @@ github.com/konsorten/go-windows-terminal-sequences v1.0.3 h1:CE8S1cTafDpPvMhIxNJ
 github.com/konsorten/go-windows-terminal-sequences v1.0.3/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/segmentio/fasthash v1.0.3 h1:EI9+KE1EwvMLBWwjpRDc+fEM+prwxDYbslddQGtrmhM=
+github.com/segmentio/fasthash v1.0.3/go.mod h1:waKX8l2N8yckOgmSsXJi7x1ZfdKZ4x7KRMzBtS3oedY=
 github.com/sirupsen/logrus v1.6.0 h1:UBcNElsrwanuuMsnGSlYmtmgbb23qDR5dG+6X6Oo89I=
 github.com/sirupsen/logrus v1.6.0/go.mod h1:7uNnSEd1DgxDLC74fIahvMZmmYsHGZGEOFrfsX/uA88=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894 h1:Cz4ceDQGXuKRnVBDTS23GTn/pU5OE2C0WrNTOYK1Uuc=
 golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-github.com/segmentio/fasthash v1.0.3 h1:EI9+KE1EwvMLBWwjpRDc+fEM+prwxDYbslddQGtrmhM=
-github.com/segmentio/fasthash v1.0.3/go.mod h1:waKX8l2N8yckOgmSsXJi7x1ZfdKZ4x7KRMzBtS3oedY=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a h1:dGzPydgVsqGcTRVwiLJ1jVbufYwmzD3LfVPLKsKg+0k=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

groupcache.go

@@ -38,9 +38,15 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-var logger *logrus.Entry
+var logger Logger
 
+// SetLogger - this is legacy to provide backwards compatibility with logrus.
 func SetLogger(log *logrus.Entry) {
+	logger = LogrusLogger{Entry: log}
+}
+
+// SetLoggerFromLogger - set the logger to an implementation of the Logger interface
+func SetLoggerFromLogger(log Logger) {
 	logger = log
 }
 
@@ -392,11 +398,12 @@ func (g *Group) load(ctx context.Context, key string, dest Sink) (value ByteView
 			}
 
 			if logger != nil {
-				logger.WithFields(logrus.Fields{
-					"err":      err,
-					"key":      key,
-					"category": "groupcache",
-				}).Errorf("error retrieving key from peer '%s'", peer.GetURL())
+				logger.Error().
+					WithFields(map[string]interface{}{
+						"err":      err,
+						"key":      key,
+						"category": "groupcache",
+					}).Printf("error retrieving key from peer '%s'", peer.GetURL())
 			}
 
 			g.Stats.PeerErrors.Add(1)

logger.go

@@ -0,0 +1,96 @@
+package groupcache
+
+import (
+	"github.com/sirupsen/logrus"
+)
+
+// Logger is a minimal interface that will allow us to use structured loggers,
+// including (but not limited to) logrus.
+type Logger interface {
+	// Error logging level
+	Error() Logger
+
+	// Warn logging level
+	Warn() Logger
+
+	// Info logging level
+	Info() Logger
+
+	// Debug logging level
+	Debug() Logger
+
+	// ErrorField is a field with an error value
+	ErrorField(label string, err error) Logger
+
+	// StringField is a field with a string value
+	StringField(label string, val string) Logger
+
+	// WithFields is willy-nilly key value pairs.
+	WithFields(fields map[string]interface{}) Logger
+
+	// Printf is called last to emit the log at the given
+	// level.
+	Printf(format string, args ...interface{})
+}
+
+// LogrusLogger is an implementation of Logger that wraps logrus... who knew?
+type LogrusLogger struct {
+	Entry *logrus.Entry
+	level logrus.Level
+}
+
+func (l LogrusLogger) Info() Logger {
+	return LogrusLogger{
+		Entry: l.Entry,
+		level: logrus.InfoLevel,
+	}
+}
+
+func (l LogrusLogger) Debug() Logger {
+	return LogrusLogger{
+		Entry: l.Entry,
+		level: logrus.DebugLevel,
+	}
+}
+
+func (l LogrusLogger) Warn() Logger {
+	return LogrusLogger{
+		Entry: l.Entry,
+		level: logrus.WarnLevel,
+	}
+}
+
+func (l LogrusLogger) Error() Logger {
+	return LogrusLogger{
+		Entry: l.Entry,
+		level: logrus.ErrorLevel,
+	}
+}
+
+func (l LogrusLogger) WithFields(fields map[string]interface{}) Logger {
+	return LogrusLogger{
+		Entry: l.Entry.WithFields(fields),
+		level: l.level,
+	}
+}
+
+// ErrorField - create a field for an error
+func (l LogrusLogger) ErrorField(label string, err error) Logger {
+	return LogrusLogger{
+		Entry: l.Entry.WithField(label, err),
+		level: l.level,
+	}
+
+}
+
+// StringField - create a field for a string.
+func (l LogrusLogger) StringField(label string, val string) Logger {
+	return LogrusLogger{
+		Entry: l.Entry.WithField(label, val),
+		level: l.level,
+	}
+}
+
+func (l LogrusLogger) Printf(format string, args ...interface{}) {
+	l.Entry.Logf(l.level, format, args...)
+}

logger_test.go

@@ -0,0 +1,77 @@
+package groupcache
+
+import (
+	"bytes"
+	"errors"
+	"github.com/sirupsen/logrus"
+	"testing"
+)
+
+// This tests the compatibility of the LogrusLogger with the previous behavior.
+func TestLogrusLogger(t *testing.T) {
+	var buf bytes.Buffer
+	l := logrus.New()
+	l.SetFormatter(&logrus.TextFormatter{
+		DisableTimestamp: true,
+	})
+	l.Out = &buf
+	e := logrus.NewEntry(l)
+	e = e.WithField("ContextKey", "ContextVal")
+	SetLogger(e)
+	logger.Error().
+		WithFields(map[string]interface{}{
+			"err":      errors.New("test error"),
+			"key":      "keyValue",
+			"category": "groupcache",
+		}).Printf("error retrieving key from peer %s", "http://127.0.0.1:8080")
+
+	interfaceOut := buf.String()
+	buf.Reset()
+	e.WithFields(logrus.Fields{
+		"err":      errors.New("test error"),
+		"key":      "keyValue",
+		"category": "groupcache",
+	}).Errorf("error retrieving key from peer %s", "http://127.0.0.1:8080")
+	logrusOut := buf.String()
+	if interfaceOut != logrusOut {
+		t.Errorf("output is not the same.\ngot:\n%s\nwant:\n%s", interfaceOut, logrusOut)
+	}
+}
+
+func BenchmarkLogrusLogger(b *testing.B) {
+	var buf bytes.Buffer
+	l := logrus.New()
+	l.SetFormatter(&logrus.TextFormatter{
+		DisableTimestamp: true,
+	})
+	l.Out = &buf
+	e := logrus.NewEntry(l)
+	SetLogger(e)
+	for i := 0; i < b.N; i++ {
+		logger.Error().
+			WithFields(map[string]interface{}{
+				"err":      errors.New("test error"),
+				"key":      "keyValue",
+				"category": "groupcache",
+			}).Printf("error retrieving key from peer %s", "http://127.0.0.1:8080")
+		buf.Reset()
+	}
+}
+
+func BenchmarkLogrus(b *testing.B) {
+	var buf bytes.Buffer
+	l := logrus.New()
+	l.SetFormatter(&logrus.TextFormatter{
+		DisableTimestamp: true,
+	})
+	l.Out = &buf
+	e := logrus.NewEntry(l)
+	for i := 0; i < b.N; i++ {
+		e.WithFields(logrus.Fields{
+			"err":      errors.New("test error"),
+			"key":      "keyValue",
+			"category": "groupcache",
+		}).Errorf("error retrieving key from peer %s", "http://127.0.0.1:8080")
+		buf.Reset()
+	}
+}