Move basic features of stats logger into base structure

stats/base.go

@@ -0,0 +1,49 @@
+package stats
+
+import (
+	"sync"
+	"time"
+
+	"github.com/rcrowley/go-metrics"
+)
+
+type base struct {
+	sync.Mutex
+	stats map[string]*baseStats
+}
+
+type baseStats struct {
+	time   metrics.Histogram
+	errors metrics.Counter
+}
+
+func (b *base) Add(name string, dur time.Duration) {
+	b.metrics(name).time.Update(int64(dur))
+}
+
+func (b *base) Error(name string) {
+	b.metrics(name).errors.Inc(1)
+}
+
+func (b *base) init() {
+	b.stats = make(map[string]*baseStats)
+}
+
+func (b *base) metrics(name string) *baseStats {
+	if _, ok := b.stats[name]; !ok {
+		b.Lock()
+		defer b.Unlock()
+
+		// Double checking being protected by mutex
+		if s, ok := b.stats[name]; ok {
+			return s
+		}
+
+		b.stats[name] = &baseStats{
+			time:   metrics.NewHistogram(metrics.NewUniformSample(1000)),
+			errors: metrics.NewCounter(),
+		}
+	}
+
+	return b.stats[name]
+}

stats/logger.go

@@ -4,30 +4,22 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"sync"
 	"time"
-
-	"github.com/rcrowley/go-metrics"
 )
 
 type Logger struct {
-	sync.Mutex
+	base
+
 	out      io.Writer
 	interval time.Duration
-	stats    map[string]*loggerStats
-}
-
-type loggerStats struct {
-	time   metrics.Histogram
-	errors metrics.Counter
 }
 
 func NewLogger(out io.Writer, interval time.Duration) *Logger {
 	l := &Logger{
 		out:      out,
 		interval: interval,
-		stats:    make(map[string]*loggerStats),
 	}
+	l.init()
 	go l.printWithInterval()
 
 	return l
@@ -37,14 +29,6 @@ func NewStdoutLogger(interval time.Duration) *Logger {
 	return NewLogger(os.Stdout, interval)
 }
 
-func (l *Logger) Add(name string, dur time.Duration) {
-	l.metrics(name).time.Update(int64(dur))
-}
-
-func (l *Logger) Error(name string) {
-	l.metrics(name).errors.Inc(1)
-}
-
 func (l *Logger) Print() {
 	for name, s := range l.stats {
 		fmt.Fprintf(l.out, "%s statistics:\n"+
@@ -78,22 +62,3 @@ func (l *Logger) printWithInterval() {
 		l.Print()
 	}
 }
-
-func (l *Logger) metrics(name string) *loggerStats {
-	if _, ok := l.stats[name]; !ok {
-		l.Lock()
-		defer l.Unlock()
-
-		// Double checking being protected by mutex
-		if s, ok := l.stats[name]; ok {
-			return s
-		}
-
-		l.stats[name] = &loggerStats{
-			time:   metrics.NewHistogram(metrics.NewUniformSample(1000)),
-			errors: metrics.NewCounter(),
-		}
-	}
-
-	return l.stats[name]
-}