feat: customize text log level styling

go.mod

@@ -3,6 +3,7 @@ module github.com/lvlcn-t/loggerhead
 go 1.22
 
 require (
+	github.com/charmbracelet/lipgloss v0.12.1
 	github.com/charmbracelet/log v0.4.0
 	github.com/remychantenay/slog-otel v1.3.2
 	go.opentelemetry.io/otel v1.28.0
@@ -12,19 +13,18 @@ require (
 
 require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
-	github.com/charmbracelet/lipgloss v0.12.1 // indirect
 	github.com/charmbracelet/x/ansi v0.1.4 // indirect
 	github.com/go-logfmt/logfmt v0.6.0 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mattn/go-runewidth v0.0.15 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
 	github.com/muesli/termenv v0.15.2 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	go.opentelemetry.io/otel/metric v1.28.0 // indirect
 	go.opentelemetry.io/otel/trace v1.28.0 // indirect
-	golang.org/x/exp v0.0.0-20240716175740-e3f259677ff7 // indirect
+	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 )

go.sum

@@ -25,6 +25,8 @@ github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWE
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
 github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
+github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
 github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -48,6 +50,8 @@ go.opentelemetry.io/otel/trace v1.28.0 h1:GhQ9cUuQGmNDd5BTCP2dAvv75RdMxEfTmYejp+
 go.opentelemetry.io/otel/trace v1.28.0/go.mod h1:jPyXzNPg6da9+38HEwElrQiHlVMTnVfM3/yv2OlIHaI=
 golang.org/x/exp v0.0.0-20240716175740-e3f259677ff7 h1:wDLEX9a7YQoKdKNQt88rtydkqDxeGaBUTnIYc3iG/mA=
 golang.org/x/exp v0.0.0-20240716175740-e3f259677ff7/go.mod h1:M4RDyNAINzryxdtnbRXRL/OHtkFuWGRjvuhBJpk2IlY=
+golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 h1:2dVuKD2vS7b0QIHQbpyTISPd0LeHDbnYEryqj5Q1ug8=
+golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56/go.mod h1:M4RDyNAINzryxdtnbRXRL/OHtkFuWGRjvuhBJpk2IlY=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

internal/logger/core.go

@@ -11,50 +11,50 @@ var _ Logger = (*logger)(nil)
 
 // Logger is a interface that provides logging methods.
 type Logger interface {
-	// Debug logs at LevelDebug.
+	// Debug logs at [LevelDebug].
 	Debug(msg string, args ...any)
-	// Debugf logs at LevelDebug.
-	// Arguments are handled in the manner of fmt.Printf.
+	// Debugf logs at [LevelDebug].
+	// Arguments are handled in the manner of [fmt.Printf].
 	Debugf(msg string, args ...any)
-	// DebugContext logs at LevelDebug with the given context.
+	// DebugContext logs at [LevelDebug] with the given context.
 	DebugContext(ctx context.Context, msg string, args ...any)
-	// Info logs at LevelInfo.
+	// Info logs at [LevelInfo].
 	Info(msg string, args ...any)
-	// Infof logs at LevelInfo.
-	// Arguments are handled in the manner of fmt.Printf.
+	// Infof logs at [LevelInfo].
+	// Arguments are handled in the manner of [fmt.Printf].
 	Infof(msg string, args ...any)
-	// InfoContext logs at LevelInfo with the given context.
+	// InfoContext logs at [LevelInfo] with the given context.
 	InfoContext(ctx context.Context, msg string, args ...any)
-	// Warn logs at LevelWarn.
+	// Warn logs at [LevelWarn].
 	Warn(msg string, args ...any)
-	// Warnf logs at LevelWarn.
-	// Arguments are handled in the manner of fmt.Printf.
+	// Warnf logs at [LevelWarn].
+	// Arguments are handled in the manner of [fmt.Printf].
 	Warnf(msg string, args ...any)
-	// WarnContext logs at LevelWarn with the given context.
+	// WarnContext logs at [LevelWarn] with the given context.
 	WarnContext(ctx context.Context, msg string, args ...any)
-	// Error logs at LevelError.
+	// Error logs at [LevelError].
 	Error(msg string, args ...any)
-	// Errorf logs at LevelError.
-	// Arguments are handled in the manner of fmt.Printf.
+	// Errorf logs at [LevelError].
+	// Arguments are handled in the manner of [fmt.Printf].
 	Errorf(msg string, args ...any)
-	// ErrorContext logs at LevelError with the given context.
+	// ErrorContext logs at [LevelError] with the given context.
 	ErrorContext(ctx context.Context, msg string, args ...any)
-	// Panic logs at LevelPanic and then panics with the given message.
+	// Panic logs at [LevelPanic] and then panics with the given message.
 	Panic(msg string, args ...any)
-	// Panicf logs at LevelPanic and then panics.
-	// Arguments are handled in the manner of fmt.Printf.
+	// Panicf logs at [LevelPanic] and then panics.
+	// Arguments are handled in the manner of [fmt.Printf].
 	Panicf(msg string, args ...any)
-	// PanicContext logs at LevelPanic with the given context and then panics with the given message.
+	// PanicContext logs at [LevelPanic] with the given context and then panics with the given message.
 	PanicContext(ctx context.Context, msg string, args ...any)
-	// Fatal logs at LevelFatal and then calls os.Exit(1).
+	// Fatal logs at [LevelFatal] and then calls [os.Exit](1).
 	Fatal(msg string, args ...any)
-	// Fatalf logs at LevelFatal and then calls os.Exit(1).
-	// Arguments are handled in the manner of fmt.Printf.
+	// Fatalf logs at [LevelFatal] and then calls [os.Exit](1).
+	// Arguments are handled in the manner of [fmt.Printf].
 	Fatalf(msg string, args ...any)
-	// FatalContext logs at LevelFatal with the given context and then calls os.Exit(1).
+	// FatalContext logs at [LevelFatal] with the given context and then calls [os.Exit](1).
 	FatalContext(ctx context.Context, msg string, args ...any)
 
-	// With calls Logger.With on the default logger.
+	// With returns a Logger that has the given attributes.
 	With(args ...any) Logger
 	// WithGroup returns a Logger that starts a group, if name is non-empty.
 	// The keys of all attributes added to the Logger will be qualified by the given
@@ -75,15 +75,15 @@ type Logger interface {
 	//     into an Attr.
 	//   - Otherwise, the argument is treated as a value with key "!BADKEY".
 	Log(ctx context.Context, level Level, msg string, args ...any)
-	// LogAttrs is a more efficient version of [Logger.Log] that accepts only Attrs.
+	// LogAttrs is a more efficient version of [Logger].Log that accepts only Attrs.
 	LogAttrs(ctx context.Context, level Level, msg string, attrs ...slog.Attr)
 
-	// Handler returns l's Handler.
+	// Handler returns the [slog.Handler] that the Logger emits log records to.
 	Handler() slog.Handler
-	// Enabled reports whether l emits log records at the given context and level.
+	// Enabled reports whether the [Logger] emits log records at the given context and level.
 	Enabled(ctx context.Context, level Level) bool
 
-	// ToSlog returns the underlying slog.Logger.
+	// ToSlog returns the underlying [slog.Logger].
 	ToSlog() *slog.Logger
 }
 
@@ -152,35 +152,22 @@ func (l *logger) LogAttrs(ctx context.Context, level Level, msg string, attrs ..
 }
 
 // logAttrs emits a log record with the current time and the given level, message, and attributes.
+// Must be called by a public log method to ensure that the caller is correct.
 func (l *logger) logAttrs(ctx context.Context, level Level, msg string, a ...any) {
 	if !l.Enabled(ctx, level) {
 		return
 	}
 
-	pc := getCaller(3)
-
-	r := slog.NewRecord(time.Now(), level, msg, pc)
+	// skip is the number of stack frames to skip to find the caller.
+	// We need to skip calling runtime.Callers, this function and the public log function.
+	const skip = 3
+	var pcs [1]uintptr
+	runtime.Callers(skip, pcs[:])
+	r := slog.NewRecord(time.Now(), level, msg, pcs[0])
 	r.Add(a...)
 	if ctx == nil {
 		ctx = context.Background()
 	}
 
 	_ = l.Handler().Handle(ctx, r)
 }
-
-// getCaller returns the program counter of the caller at a given depth.
-// The depth is the number of stack frames to ascend, with 0 identifying the
-// getCaller function itself, 1 identifying the caller that invoked getCaller,
-// and so on.
-//
-// Example:
-//
-//	pc := getCaller(1) // Returns the program counter of the caller of the function that invoked getCaller.
-//	pc := getCaller(2) // Returns the program counter of the caller of the function that invoked the function that invoked getCaller.
-func getCaller(depth uint8) uintptr {
-	d := int(depth) + 1
-
-	var pcs [1]uintptr
-	runtime.Callers(d, pcs[:])
-	return pcs[0]
-}

internal/logger/extensions.go

@@ -50,21 +50,24 @@ func (l *logger) PanicContext(ctx context.Context, msg string, args ...any) {
 	panic(msg)
 }
 
+// exit is a variable for [os.Exit].
+var exit = os.Exit
+
 // Fatal logs at [LevelFatal] and then calls os.Exit(1).
 func (l *logger) Fatal(msg string, args ...any) {
 	l.logAttrs(context.Background(), LevelFatal, msg, args...)
-	os.Exit(1)
+	exit(1)
 }
 
 // Fatalf logs at LevelFatal and then calls os.Exit(1).
 // Arguments are handled in the manner of fmt.Printf.
 func (l *logger) Fatalf(msg string, args ...any) {
 	l.logAttrs(context.Background(), LevelFatal, fmt.Sprintf(msg, args...))
-	os.Exit(1)
+	exit(1)
 }
 
 // FatalContext logs at [LevelFatal] and then calls os.Exit(1).
 func (l *logger) FatalContext(ctx context.Context, msg string, args ...any) {
 	l.logAttrs(ctx, LevelFatal, msg, args...)
-	os.Exit(1)
+	exit(1)
 }

internal/logger/extensions_test.go

@@ -157,7 +157,7 @@ func TestLogger_LevelExtensions(t *testing.T) {
 	}
 }
 
-func TestLogger_PanicLevel(t *testing.T) {
+func TestLogger_Panic_FatalLevels(t *testing.T) { //nolint:gocyclo // Either higher complexity or code duplication
 	tests := []struct {
 		name    string
 		attrs   []any
@@ -220,10 +220,71 @@ func TestLogger_PanicLevel(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "fatal level",
+			logFunc: func(l Logger, msg string, args ...any) {
+				l.Fatal(msg, args...)
+			},
+			handler: test.MockHandler{
+				HandleFunc: func(ctx context.Context, r slog.Record) error {
+					level := LevelFatal
+					if r.Level != level {
+						t.Errorf("Expected level to be [%s], got [%s]", getLevelString(level), r.Level)
+					}
+					if r.NumAttrs() != 0 {
+						t.Errorf("Expected 0 attributes, got %d", r.NumAttrs())
+					}
+					return nil
+				},
+			},
+		},
+		{
+			name: "fatalf level",
+			logFunc: func(l Logger, msg string, args ...any) {
+				l.Fatalf(msg, args...)
+			},
+			handler: test.MockHandler{
+				HandleFunc: func(ctx context.Context, r slog.Record) error {
+					level := LevelFatal
+					if r.Level != level {
+						t.Errorf("Expected level to be [%s], got [%s]", getLevelString(level), r.Level)
+					}
+					if r.NumAttrs() != 0 {
+						t.Errorf("Expected 0 attributes, got %d", r.NumAttrs())
+					}
+					return nil
+				},
+			},
+		},
+		{
+			name: "fatal context level",
+			logFunc: func(l Logger, msg string, args ...any) {
+				l.FatalContext(context.Background(), msg, args...)
+			},
+			handler: test.MockHandler{
+				HandleFunc: func(ctx context.Context, r slog.Record) error {
+					level := LevelFatal
+					if r.Level != level {
+						t.Errorf("Expected level to be [%s], got [%s]", getLevelString(level), r.Level)
+					}
+					if r.NumAttrs() != 0 {
+						t.Errorf("Expected 0 attributes, got %d", r.NumAttrs())
+					}
+					return nil
+				},
+			},
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			exit = func(code int) {
+				if code != 1 {
+					t.Errorf("Expected exit code 1, got %d", code)
+				}
+				panic("os.Exit(1)")
+			}
+
 			l := NewLogger(Options{Handler: tt.handler})
 			defer func() {
 				if r := recover(); r == nil {

internal/logger/level.go

@@ -19,6 +19,7 @@ const (
 	LevelFatal  Level = slog.Level(16)
 )
 
+// LevelNames is a map of log levels to their respective names.
 var LevelNames = map[Level]string{
 	LevelTrace:  "TRACE",
 	LevelDebug:  "DEBUG",
@@ -30,6 +31,18 @@ var LevelNames = map[Level]string{
 	LevelFatal:  "FATAL",
 }
 
+// LevelColors is a map of log levels to their respective ansi color codes.
+var LevelColors = map[Level]string{
+	LevelTrace:  "240", // TRACE - Light Gray
+	LevelDebug:  "63",  // DEBUG - Blue
+	LevelInfo:   "86",  // INFO - Cyan
+	LevelNotice: "220", // NOTICE - Yellow
+	LevelWarn:   "192", // WARN - Orange
+	LevelError:  "204", // ERROR - Red
+	LevelPanic:  "134", // PANIC - Purple
+	LevelFatal:  "160", // FATAL - Dark Red
+}
+
 // getLevel returns the integer value of the given level string.
 // If the level is not recognized, it returns LevelInfo.
 func getLevel(level string) int {

internal/logger/opts.go

@@ -26,8 +26,8 @@ func newDefaultOptions() Options {
 	}
 }
 
-// getOptions returns the first Options in the slice if it exists; otherwise, it returns the default Options.
-func getOptions(o ...Options) Options {
+// newOptions creates a new Options instance with the provided Options merged with the default Options.
+func newOptions(o ...Options) Options {
 	opts := newDefaultOptions()
 	if len(o) > 0 {
 		return o[0].merge(opts)