benchmark_test.go

@@ -0,0 +1,65 @@
+package zapjournald
+
+import (
+	"testing"
+
+	"github.com/ssgreg/journald"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type nopSync struct{}
+
+func (nopSync) Write([]byte) (int, error) { return 0, nil }
+func (nopSync) Sync() error               { return nil }
+
+func BenchmarkLogger(b *testing.B) {
+	zc := zap.NewProductionConfig()
+	zc.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	zc.Level = zap.NewAtomicLevelAt(zap.InfoLevel)
+
+	b.Run("standard", func(b *testing.B) {
+		encoder := zapcore.NewJSONEncoder(zc.EncoderConfig)
+		core := zapcore.NewCore(encoder, nopSync{}, zc.Level)
+		coreWithContext := core.With([]zapcore.Field{
+			SyslogFacility(LogDaemon),
+			SyslogIdentifier(),
+			SyslogPid()})
+		l := zap.New(coreWithContext)
+		benchmarkLog(b, l)
+	})
+	b.Run("journald", func(b *testing.B) {
+		encoder := zapcore.NewJSONEncoder(zc.EncoderConfig)
+		core := NewCore(zc.Level, encoder, &journald.Journal{}, SyslogFields)
+		core.j.TestModeEnabled = true // Disable actual writing to the journal.
+
+		coreWithContext := core.With([]zapcore.Field{
+			SyslogFacility(LogDaemon),
+			SyslogIdentifier(),
+			SyslogPid(),
+		})
+		l := zap.New(coreWithContext)
+		benchmarkLog(b, l)
+	})
+}
+
+func benchmarkLog(b *testing.B, l *zap.Logger) {
+	b.Run("no fields", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			l.Info("Simple log message")
+		}
+	})
+	b.Run("application fields", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			l.Info("Simple log message", zap.Uint32("count", 123), zap.String("details", "nothing"))
+		}
+	})
+	b.Run("journald fields", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			l.Info("Simple log message", SyslogIdentifier())
+		}
+	})
+}

encoder.go

@@ -0,0 +1,70 @@
+package zapjournald
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"go.uber.org/zap/buffer"
+)
+
+var pool = buffer.NewPool()
+
+func encodeJournaldField(buf *buffer.Buffer, key string, value any) {
+	switch v := value.(type) {
+	case string:
+		writeField(buf, key, v)
+	case []byte:
+		writeFieldBytes(buf, key, v)
+	default:
+		writeField(buf, key, fmt.Sprint(v))
+	}
+}
+
+func writeFieldBytes(buf *buffer.Buffer, name string, value []byte) {
+	buf.Write([]byte(name))
+	if bytes.ContainsRune(value, '\n') {
+		// According to the format, if the value includes a newline
+		// need to write the field name, plus a newline, then the
+		// size (64bit LE), the field data and a final newline.
+
+		buf.Write([]byte{'\n'})
+		appendUint64Binary(buf, uint64(len(value)))
+	} else {
+		buf.Write([]byte{'='})
+	}
+	buf.Write(value)
+	buf.Write([]byte{'\n'})
+}
+
+func writeField(buf *buffer.Buffer, name string, value string) {
+	buf.Write([]byte(name))
+	if strings.ContainsRune(value, '\n') {
+		// According to the format, if the value includes a newline
+		// need to write the field name, plus a newline, then the
+		// size (64bit LE), the field data and a final newline.
+
+		buf.Write([]byte{'\n'})
+		// 1 allocation here.
+		// binary.Write(w, binary.LittleEndian, uint64(len(value)))
+		appendUint64Binary(buf, uint64(len(value)))
+	} else {
+		buf.Write([]byte{'='})
+	}
+	buf.WriteString(value)
+	buf.Write([]byte{'\n'})
+}
+
+func appendUint64Binary(buf *buffer.Buffer, v uint64) {
+	// Copied from https://github.com/golang/go/blob/go1.21.3/src/encoding/binary/binary.go#L119
+	buf.Write([]byte{
+		byte(v),
+		byte(v >> 8),
+		byte(v >> 16),
+		byte(v >> 24),
+		byte(v >> 32),
+		byte(v >> 40),
+		byte(v >> 48),
+		byte(v >> 56),
+	})
+}

zapjournald.go

@@ -2,6 +2,9 @@ package zapjournald
 
 import (
 	"fmt"
+	"math"
+	"strconv"
+	"time"
 
 	"github.com/ssgreg/journald"
 	"go.uber.org/zap/zapcore"
@@ -65,47 +68,38 @@ func (core *Core) Check(entry zapcore.Entry, checked *zapcore.CheckedEntry) *zap
 // If called, Write should always log the Entry and Fields; it should not
 // replicate the logic of Check.
 func (core *Core) Write(entry zapcore.Entry, fields []zapcore.Field) error {
+	prio, err := zapLevelToJournald(entry.Level)
+	if err != nil {
+		return err
+	}
+
+	b := pool.Get()
+	defer b.Free()
+
+	writeField(b, "PRIORITY", strconv.Itoa(int(prio)))
+
+	if len(core.contextStructuredFields) != 0 {
+		for k, v := range core.contextStructuredFields {
+			encodeJournaldField(b, k, v)
+		}
+		for _, field := range fields {
+			if _, isJournalField := core.storedFieldNames[field.Key]; isJournalField {
+				encodeJournaldField(b, field.Key, getFieldValue(field))
+			}
+		}
+	}
+
 	// Generate the message.
 	buffer, err := core.encoder.EncodeEntry(entry, fields)
 	if err != nil {
 		return fmt.Errorf("failed to encode log entry: %w", err)
 	}
+	defer buffer.Free()
 
-	message := buffer.String()
+	writeFieldBytes(b, "MESSAGE", buffer.Bytes())
-
-	structuredFields := maps.Clone(core.contextStructuredFields)
-	for _, field := range fields {
-		if _, isJournalField := core.storedFieldNames[field.Key]; isJournalField {
-			structuredFields[field.Key] = getFieldValue(field)
-		}
-	}
 
 	// Write the message.
-	switch entry.Level {
+	return core.j.WriteMsg(b.Bytes())
-	case zapcore.DebugLevel:
-		return core.j.Send(message, journald.PriorityDebug, structuredFields)
-
-	case zapcore.InfoLevel:
-		return core.j.Send(message, journald.PriorityInfo, structuredFields)
-
-	case zapcore.WarnLevel:
-		return core.j.Send(message, journald.PriorityWarning, structuredFields)
-
-	case zapcore.ErrorLevel:
-		return core.j.Send(message, journald.PriorityErr, structuredFields)
-
-	case zapcore.DPanicLevel:
-		return core.j.Send(message, journald.PriorityCrit, structuredFields)
-
-	case zapcore.PanicLevel:
-		return core.j.Send(message, journald.PriorityCrit, structuredFields)
-
-	case zapcore.FatalLevel:
-		return core.j.Send(message, journald.PriorityCrit, structuredFields)
-
-	default:
-		return fmt.Errorf("unknown log level: %v", entry.Level)
-	}
 }
 
 // Sync flushes buffered logs (not used).
@@ -141,20 +135,29 @@ func getFieldValue(f zapcore.Field) interface{} {
 		zapcore.ErrorType,
 		zapcore.SkipType:
 		return f.Interface
-	case zapcore.DurationType,
+	case zapcore.DurationType:
-		zapcore.Float64Type,
+		return time.Duration(f.Integer).String()
-		zapcore.Float32Type,
+	case zapcore.Float64Type:
-		zapcore.Int64Type,
+		// See https://github.com/uber-go/zap/blob/v1.26.0/buffer/buffer.go#L79
+		f := math.Float64frombits(uint64(f.Integer))
+		return strconv.FormatFloat(f, 'f', -1, 64)
+	case zapcore.Float32Type:
+		f := math.Float32frombits(uint32(f.Integer))
+		return strconv.FormatFloat(float64(f), 'f', -1, 32)
+	case zapcore.Int64Type,
 		zapcore.Int32Type,
 		zapcore.Int16Type,
-		zapcore.Int8Type,
+		zapcore.Int8Type:
+		return strconv.FormatInt(f.Integer, 10)
+	case
 		zapcore.Uint64Type,
 		zapcore.Uint32Type,
 		zapcore.Uint16Type,
 		zapcore.Uint8Type,
-		zapcore.UintptrType,
+		zapcore.UintptrType:
-		zapcore.BoolType:
+		return strconv.FormatUint(uint64(f.Integer), 10)
-		return f.Integer
+	case zapcore.BoolType:
+		return strconv.FormatBool(f.Integer == 1)
 	case zapcore.StringType:
 		return f.String
 	case zapcore.TimeType:
@@ -162,8 +165,29 @@ func getFieldValue(f zapcore.Field) interface{} {
 			// for example: zap.Time("k", time.Unix(100900, 0).In(time.UTC)) - will produce: "100900000000000 UTC" (result in nanoseconds)
 			return fmt.Sprintf("%d %v", f.Integer, f.Interface)
 		}
-		return f.Integer
+		return strconv.FormatUint(uint64(f.Integer), 10)
 	default:
 		panic(fmt.Sprintf("unknown field type: %v", f))
 	}
 }
+
+func zapLevelToJournald(l zapcore.Level) (journald.Priority, error) {
+	switch l {
+	case zapcore.DebugLevel:
+		return journald.PriorityDebug, nil
+	case zapcore.InfoLevel:
+		return journald.PriorityInfo, nil
+	case zapcore.WarnLevel:
+		return journald.PriorityWarning, nil
+	case zapcore.ErrorLevel:
+		return journald.PriorityErr, nil
+	case zapcore.DPanicLevel:
+		return journald.PriorityCrit, nil
+	case zapcore.PanicLevel:
+		return journald.PriorityCrit, nil
+	case zapcore.FatalLevel:
+		return journald.PriorityCrit, nil
+	default:
+		return 0, fmt.Errorf("unknown log level: %v", l)
+	}
+}