feat(logger): add logger context utilities

Co-authored-by: Gaze <gazenw@users.noreply.github.com>

pkg/logger/context.go

@@ -6,34 +6,73 @@ import (
 	"os"
 )
 
-// DebugContext logs at [LevelDebug] with the given context.
+type loggerKey struct{}
+
+// FromContext returns the logger from the context. If no logger is found, a new
+func FromContext(ctx context.Context) *slog.Logger {
+	if ctx == nil {
+		return logger.With()
+	}
+
+	if log, ok := ctx.Value(loggerKey{}).(*slog.Logger); ok {
+		return log
+	}
+
+	return logger.With()
+}
+
+// NewContext returns a new context with logger attached.
+func NewContext(ctx context.Context, log *slog.Logger) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	return context.WithValue(ctx, loggerKey{}, log)
+}
+
+// WithContext returns a new context with given logger attributes.
+func WithContext(ctx context.Context, args ...any) context.Context {
+	return NewContext(ctx, FromContext(ctx).With(args...))
+}
+
+// WithGroupContext returns a new context with given group.
+func WithGroupContext(ctx context.Context, group string) context.Context {
+	return NewContext(ctx, FromContext(ctx).WithGroup(group))
+}
+
+// DebugContext logs at [LevelDebug] from logger in the given context.
 func DebugContext(ctx context.Context, msg string, args ...any) {
-	log(ctx, logger, slog.LevelDebug, msg, args...)
+	log(ctx, FromContext(ctx), slog.LevelDebug, msg, args...)
 }
 
-// InfoContext logs at [LevelInfo] with the given context.
+// InfoContext logs at [LevelInfo] from logger in the given context.
 func InfoContext(ctx context.Context, msg string, args ...any) {
-	log(ctx, logger, slog.LevelInfo, msg, args...)
+	log(ctx, FromContext(ctx), slog.LevelInfo, msg, args...)
 }
 
-// WarnContext logs at [LevelWarn] with the given context.
+// WarnContext logs at [LevelWarn] from logger in the given context.
 func WarnContext(ctx context.Context, msg string, args ...any) {
-	log(ctx, logger, slog.LevelWarn, msg, args...)
+	log(ctx, FromContext(ctx), slog.LevelWarn, msg, args...)
 }
 
-// ErrorContext logs at [LevelError] with an error and the given context.
+// ErrorContext logs at [LevelError] from logger in the given context.
 func ErrorContext(ctx context.Context, msg string, err error, args ...any) {
-	log(ctx, logger, slog.LevelError, msg, append(args, AttrError(err))...)
+	log(ctx, FromContext(ctx), slog.LevelError, msg, append(args, AttrError(err))...)
 }
 
-// PanicContext logs at [LevelPanic] and then panics with the given context.
+// PanicContext logs at [LevelPanic] and then panics from logger in the given context.
 func PanicContext(ctx context.Context, msg string, args ...any) {
-	log(ctx, logger, LevelPanic, msg, args...)
+	log(ctx, FromContext(ctx), LevelPanic, msg, args...)
 	panic(msg)
 }
 
-// FatalContext logs at [LevelFatal] and then [os.Exit](1) with the given context.
+// FatalContext logs at [LevelFatal] and then [os.Exit](1) from logger in the given context.
 func FatalContext(ctx context.Context, msg string, args ...any) {
-	log(ctx, logger, LevelFatal, msg, args...)
+	log(ctx, FromContext(ctx), LevelFatal, msg, args...)
 	os.Exit(1)
 }
+
+// LogContext logs at the given level from logger in the given context.
+func LogContext(ctx context.Context, level slog.Level, msg string, args ...any) {
+	log(ctx, FromContext(ctx), level, msg, args...)
+}

pkg/logger/logger.go

@@ -51,11 +51,23 @@ func SetLevel(level slog.Level) (old slog.Level) {
 	return old
 }
 
-// With returns a new logger with given attributes.
+// With returns a Logger that includes the given attributes
+// in each output operation. Arguments are converted to
+// attributes as if by [Logger.Log].
 func With(args ...any) *slog.Logger {
 	return logger.With(args...)
 }
 
+// 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
+// name. (How that qualification happens depends on the [Handler.WithGroup]
+// method of the Logger's Handler.)
+//
+// If name is empty, WithGroup returns the receiver.
+func WithGroup(group string) *slog.Logger {
+	return logger.WithGroup(group)
+}
+
 // Debug logs at [LevelDebug].
 func Debug(msg string, args ...any) {
 	log(context.Background(), logger, slog.LevelDebug, msg, args...)
@@ -97,7 +109,7 @@ func Log(level slog.Level, msg string, args ...any) {
 
 // LogAttrs is a more efficient version of [Logger.Log] that accepts only Attrs.
 func LogAttrs(ctx context.Context, level slog.Level, msg string, attrs ...slog.Attr) {
-	logAttrs(ctx, logger, level, msg, attrs...)
+	logAttrs(ctx, FromContext(ctx), level, msg, attrs...)
 }
 
 // Config is the logger configuration.