Add logger package with performance benchmarks

logger/formatter.go

@@ -0,0 +1,77 @@
+package logger
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+	"time"
+)
+
+type Formatter interface {
+	Format(writer io.Writer, entry *Entry)
+}
+
+type textFormatter struct {
+	timeFormat string
+	prefix     string
+}
+
+type jsonFormatter struct{}
+
+func newFormatter(format Format) Formatter {
+	switch format {
+	case JSON:
+		return &jsonFormatter{}
+	default:
+		return &textFormatter{
+			timeFormat: "2006-01-02 15:04:05",
+		}
+	}
+}
+
+func (f *textFormatter) Format(writer io.Writer, entry *Entry) {
+	parts := make([]string, 0, 8)
+	parts = append(parts, entry.Time.Format(f.timeFormat))
+	parts = append(parts, entry.Level.String())
+
+	if f.prefix != "" {
+		parts = append(parts, "["+f.prefix+"]")
+	}
+
+	if entry.Caller != "" {
+		parts = append(parts, entry.Caller)
+	}
+
+	parts = append(parts, entry.Message)
+
+	if len(entry.Fields) > 0 {
+		fieldStrs := make([]string, 0, len(entry.Fields))
+		for k, v := range entry.Fields {
+			fieldStrs = append(fieldStrs, fmt.Sprintf("%s=%v", k, v))
+		}
+		parts = append(parts, strings.Join(fieldStrs, " "))
+	}
+
+	fmt.Fprintln(writer, strings.Join(parts, " "))
+}
+
+func (f *jsonFormatter) Format(writer io.Writer, entry *Entry) {
+	m := map[string]interface{}{
+		"time":    entry.Time.Format(time.RFC3339),
+		"level":   entry.Level.String(),
+		"message": entry.Message,
+	}
+
+	if entry.Caller != "" {
+		m["caller"] = entry.Caller
+	}
+
+	for k, v := range entry.Fields {
+		m[k] = v
+	}
+
+	data, _ := json.Marshal(m)
+	writer.Write(data)
+	writer.Write([]byte("\n"))
+}