Merge pull request #11 from zerodha/opts

specify options in New

benchmark_test.go

@@ -9,7 +9,7 @@ import (
 )
 
 func BenchmarkNoField(b *testing.B) {
-	logger := logf.New(io.Discard)
+	logger := logf.New(logf.Opts{Writer: io.Discard})
 	b.ReportAllocs()
 	b.ResetTimer()
 	b.RunParallel(func(p *testing.PB) {
@@ -20,7 +20,7 @@ func BenchmarkNoField(b *testing.B) {
 }
 
 func BenchmarkOneField(b *testing.B) {
-	logger := logf.New(io.Discard)
+	logger := logf.New(logf.Opts{Writer: io.Discard})
 	b.ReportAllocs()
 	b.ResetTimer()
 	b.RunParallel(func(p *testing.PB) {
@@ -31,7 +31,7 @@ func BenchmarkOneField(b *testing.B) {
 }
 
 func BenchmarkThreeFields(b *testing.B) {
-	logger := logf.New(io.Discard)
+	logger := logf.New(logf.Opts{Writer: io.Discard})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -45,7 +45,7 @@ func BenchmarkThreeFields(b *testing.B) {
 }
 
 func BenchmarkErrorField(b *testing.B) {
-	logger := logf.New(io.Discard)
+	logger := logf.New(logf.Opts{Writer: io.Discard})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -59,7 +59,7 @@ func BenchmarkErrorField(b *testing.B) {
 }
 
 func BenchmarkHugePayload(b *testing.B) {
-	logger := logf.New(io.Discard)
+	logger := logf.New(logf.Opts{Writer: io.Discard})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -82,8 +82,7 @@ func BenchmarkHugePayload(b *testing.B) {
 }
 
 func BenchmarkThreeFields_WithCaller(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetCallerFrame(true, 3)
+	logger := logf.New(logf.Opts{Writer: io.Discard, CallerSkipFrameCount: 3, EnableCaller: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -97,8 +96,7 @@ func BenchmarkThreeFields_WithCaller(b *testing.B) {
 }
 
 func BenchmarkNoField_WithColor(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetColorOutput(true)
+	logger := logf.New(logf.Opts{Writer: io.Discard, EnableColor: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -110,8 +108,7 @@ func BenchmarkNoField_WithColor(b *testing.B) {
 }
 
 func BenchmarkOneField_WithColor(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetColorOutput(true)
+	logger := logf.New(logf.Opts{Writer: io.Discard, EnableColor: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 	b.RunParallel(func(p *testing.PB) {
@@ -122,8 +119,7 @@ func BenchmarkOneField_WithColor(b *testing.B) {
 }
 
 func BenchmarkThreeFields_WithColor(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetColorOutput(true)
+	logger := logf.New(logf.Opts{Writer: io.Discard, EnableColor: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -137,8 +133,7 @@ func BenchmarkThreeFields_WithColor(b *testing.B) {
 }
 
 func BenchmarkErrorField_WithColor(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetColorOutput(true)
+	logger := logf.New(logf.Opts{Writer: io.Discard, EnableColor: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 
@@ -152,8 +147,7 @@ func BenchmarkErrorField_WithColor(b *testing.B) {
 }
 
 func BenchmarkHugePayload_WithColor(b *testing.B) {
-	logger := logf.New(io.Discard)
-	logger.SetColorOutput(true)
+	logger := logf.New(logf.Opts{Writer: io.Discard, EnableColor: true})
 	b.ReportAllocs()
 	b.ResetTimer()
 

examples/main.go

@@ -1,23 +1,22 @@
 package main
 
 import (
-	"os"
 	"time"
 
 	"github.com/zerodha/logf"
 )
 
 func main() {
-	logger := logf.New(os.Stderr)
-
-	// Basic log.
+	logger := logf.New(logf.Opts{
+		EnableColor:          true,
+		Level:                logf.DebugLevel,
+		CallerSkipFrameCount: 3,
+		EnableCaller:         true,
+		TimestampFormat:      time.RFC3339Nano,
+	})
+
+	// Basic logs.
 	logger.Info("starting app")
-
-	// Enable colored output.
-	logger.SetColorOutput(true)
-
-	// Change verbosity on the fly.
-	logger.SetLevel(logf.DebugLevel)
 	logger.Debug("meant for debugging app")
 
 	// Add extra keys to the log.
@@ -26,11 +25,6 @@ func main() {
 	// Log with error key.
 	logger.Error("error fetching details", "error", "this is a dummy error")
 
-	// Enable `caller` field in the log and specify the number of frames to skip to get the caller.
-	logger.SetCallerFrame(true, 3)
-	// Change the default timestamp format.
-	logger.SetTimestampFormat(time.RFC3339Nano)
-
 	// Log the error and set exit code as 1.
 	logger.Fatal("goodbye world")
 }

log.go

@@ -6,7 +6,6 @@ import (
 	stdlog "log"
 	"os"
 	"runtime"
-	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -23,26 +22,31 @@ var (
 	bufPool byteBufferPool
 )
 
+type Opts struct {
+	Writer               io.Writer
+	Level                Level
+	TimestampFormat      string
+	EnableColor          bool
+	EnableCaller         bool
+	CallerSkipFrameCount int
+}
+
 // Logger is the interface for all log operations
 // related to emitting logs.
 type Logger struct {
-	out                  io.Writer // Output destination.
-	level                Level     // Verbosity of logs.
-	tsFormat             string    // Timestamp format.
-	enableColor          bool      // Colored output.
-	enableCaller         bool      // Print caller information.
-	callerSkipFrameCount int       // Number of frames to skip when detecting caller
+	out io.Writer // Output destination.
+	Opts
 }
 
 // Severity level of the log.
 type Level int
 
 const (
-	DebugLevel Level = iota // 0
-	InfoLevel               // 1
-	WarnLevel               // 2
-	ErrorLevel              // 3
-	FatalLevel              // 4
+	DebugLevel Level = iota + 1 // 1
+	InfoLevel                   // 2
+	WarnLevel                   // 3
+	ErrorLevel                  // 4
+	FatalLevel                  // 5
 )
 
 // ANSI escape codes for coloring text in console.
@@ -64,20 +68,21 @@ var colorLvlMap = [...]string{
 }
 
 // New instantiates a logger object.
-// It writes to `stderr` as the default and it's non configurable.
-func New(out io.Writer) Logger {
-	// Initialise logger with sane defaults.
-	if out == nil {
-		out = os.Stderr
+func New(opts Opts) Logger {
+	// Initialise fallbacks if unspecified by user.
+	if opts.Writer == nil {
+		opts.Writer = os.Stderr
+	}
+	if opts.TimestampFormat == "" {
+		opts.TimestampFormat = defaultTSFormat
+	}
+	if opts.Level == 0 {
+		opts.Level = InfoLevel
 	}
 
 	return Logger{
-		out:                  newSyncWriter(out),
-		level:                InfoLevel,
-		tsFormat:             defaultTSFormat,
-		enableColor:          false,
-		enableCaller:         false,
-		callerSkipFrameCount: 0,
+		out:  newSyncWriter(opts.Writer),
+		Opts: opts,
 	}
 }
 
@@ -124,38 +129,6 @@ func (l Level) String() string {
 	}
 }
 
-// SetLevel sets the verbosity for logger.
-// Verbosity can be dynamically changed by the caller.
-func (l Logger) SetLevel(lvl Level) Logger {
-	l.level = lvl
-	return l
-}
-
-// SetWriter sets the output writer for the logger
-func (l Logger) SetWriter(w io.Writer) Logger {
-	l.out = &syncWriter{w: w}
-	return l
-}
-
-// SetTimestampFormat sets the timestamp format for the `timestamp` key.
-func (l Logger) SetTimestampFormat(f string) Logger {
-	l.tsFormat = f
-	return l
-}
-
-// SetColorOutput enables/disables colored output.
-func (l Logger) SetColorOutput(color bool) Logger {
-	l.enableColor = color
-	return l
-}
-
-// SetCallerFrame enables/disables the caller source in the log line.
-func (l Logger) SetCallerFrame(caller bool, depth int) Logger {
-	l.enableCaller = caller
-	l.callerSkipFrameCount = depth
-	return l
-}
-
 // Debug emits a debug log line.
 func (l Logger) Debug(msg string, fields ...any) {
 	l.handleLog(msg, DebugLevel, fields...)
@@ -188,20 +161,20 @@ func (l Logger) Fatal(msg string, fields ...any) {
 func (l Logger) handleLog(msg string, lvl Level, fields ...any) {
 	// Discard the log if the verbosity is higher.
 	// For eg, if the lvl is `3` (error), but the incoming message is `0` (debug), skip it.
-	if lvl < l.level {
+	if lvl < l.Opts.Level {
 		return
 	}
 
 	// Get a buffer from the pool.
 	buf := bufPool.Get()
 
 	// Write fixed keys to the buffer before writing user provided ones.
-	writeTimeToBuf(buf, l.tsFormat, lvl, l.enableColor)
-	writeToBuf(buf, "level", lvl, lvl, l.enableColor, true)
-	writeStringToBuf(buf, "message", msg, lvl, l.enableColor, true)
+	writeTimeToBuf(buf, l.Opts.TimestampFormat, lvl, l.Opts.EnableColor)
+	writeToBuf(buf, "level", lvl, lvl, l.Opts.EnableColor, true)
+	writeStringToBuf(buf, "message", msg, lvl, l.Opts.EnableColor, true)
 
-	if l.enableCaller {
-		writeToBuf(buf, "caller", caller(l.callerSkipFrameCount), lvl, l.enableColor, true)
+	if l.Opts.EnableCaller {
+		writeCallerToBuf(buf, "caller", l.Opts.CallerSkipFrameCount, lvl, l.EnableColor, true)
 	}
 
 	// Format the line as logfmt.
@@ -230,7 +203,7 @@ func (l Logger) handleLog(msg string, lvl Level, fields ...any) {
 			val = fields[i]
 		}
 
-		writeToBuf(buf, key, val, lvl, l.enableColor, space)
+		writeToBuf(buf, key, val, lvl, l.Opts.EnableColor, space)
 		count++
 	}
 	buf.AppendString("\n")
@@ -273,6 +246,26 @@ func writeStringToBuf(buf *byteBuffer, key string, val string, lvl Level, color,
 	}
 }
 
+func writeCallerToBuf(buf *byteBuffer, key string, depth int, lvl Level, color, space bool) {
+	_, file, line, ok := runtime.Caller(depth)
+	if !ok {
+		file = "???"
+		line = 0
+	}
+	if color {
+		buf.AppendString(getColoredKey(key, lvl))
+	} else {
+		buf.AppendString(key)
+	}
+	buf.AppendByte('=')
+	escapeAndWriteString(buf, file)
+	buf.AppendByte(':')
+	buf.AppendInt(int64(line))
+	if space {
+		buf.AppendByte(' ')
+	}
+}
+
 // writeToBuf takes key, value and additional options to write to the buffer in logfmt.
 func writeToBuf(buf *byteBuffer, key string, val any, lvl Level, color, space bool) {
 	if color {
@@ -323,16 +316,6 @@ func getColoredKey(k string, lvl Level) string {
 	return colorLvlMap[lvl] + k + reset
 }
 
-// caller returns the file:line of the caller.
-func caller(depth int) string {
-	_, file, line, ok := runtime.Caller(depth)
-	if !ok {
-		file = "???"
-		line = 0
-	}
-	return file + ":" + strconv.Itoa(line)
-}
-
 // checkEscapingRune returns true if the rune is to be escaped.
 func checkEscapingRune(r rune) bool {
 	return r == '=' || r == ' ' || r == '"' || r == utf8.RuneError