restructured logger from budigt

console_stream.go

@@ -0,0 +1,75 @@
+package splinter
+
+import (
+	"context"
+	"io"
+	"log/slog"
+	"os"
+)
+
+// ConsoleFormat selects the output style for ConsoleStream.
+type ConsoleFormat int
+
+const (
+	// ConsoleJSON writes structured JSON lines.
+	ConsoleJSON ConsoleFormat = iota
+	// ConsolePretty writes human-readable text (slog.TextHandler).
+	ConsolePretty
+)
+
+// ConsoleStream writes log records to an io.Writer (default os.Stderr) using
+// the standard library's slog handlers.
+type ConsoleStream struct {
+	logger *slog.Logger
+	level  Level
+}
+
+// ConsoleOption configures a ConsoleStream.
+type ConsoleOption func(*consoleConfig)
+
+type consoleConfig struct {
+	writer io.Writer
+}
+
+// ConsoleWriter overrides the output destination (default: os.Stderr).
+func ConsoleWriter(w io.Writer) ConsoleOption {
+	return func(c *consoleConfig) { c.writer = w }
+}
+
+// NewConsoleStream creates a console stream.
+func NewConsoleStream(format ConsoleFormat, level Level, opts ...ConsoleOption) *ConsoleStream {
+	cfg := &consoleConfig{writer: os.Stderr}
+	for _, o := range opts {
+		o(cfg)
+	}
+
+	handlerOpts := &slog.HandlerOptions{Level: level}
+
+	var handler slog.Handler
+	switch format {
+	case ConsolePretty:
+		handler = slog.NewTextHandler(cfg.writer, handlerOpts)
+	default:
+		handler = slog.NewJSONHandler(cfg.writer, handlerOpts)
+	}
+	return &ConsoleStream{logger: slog.New(handler), level: level}
+}
+
+// Name implements Stream.
+func (s *ConsoleStream) Name() string { return "console" }
+
+// Write implements Stream.
+func (s *ConsoleStream) Write(ctx context.Context, rec Record) error {
+	args := make([]any, 0, len(rec.Attrs)*2)
+	for k, v := range rec.Attrs {
+		args = append(args, k, v)
+	}
+	s.logger.Log(ctx, rec.Level, rec.Message, args...)
+	return nil
+}
+
+// Enabled implements Stream.
+func (s *ConsoleStream) Enabled(level Level) bool { return level >= s.level }
+
+// Close implements Stream. No-op for console output.
+func (s *ConsoleStream) Close() error { return nil }