logger: otlp support

logger/logfmt.go

@@ -0,0 +1,79 @@
+package logger
+
+import (
+	"bytes"
+	"context"
+	"log/slog"
+	"slices"
+	"strings"
+	"sync"
+)
+
+type logfmt struct {
+	buf  *bytes.Buffer
+	txt  slog.Handler
+	next slog.Handler
+	mu   sync.Mutex
+}
+
+func newLogFmtHandler(next slog.Handler) slog.Handler {
+
+	buf := bytes.NewBuffer([]byte{})
+
+	h := &logfmt{
+		buf:  buf,
+		next: next,
+		txt: slog.NewTextHandler(buf, &slog.HandlerOptions{
+			ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+				if a.Key == slog.TimeKey && len(groups) == 0 {
+					return slog.Attr{}
+				}
+				if a.Key == slog.LevelKey && len(groups) == 0 {
+					return slog.Attr{}
+				}
+				return a
+			},
+		}),
+	}
+
+	return h
+}
+
+func (h *logfmt) Enabled(ctx context.Context, lvl slog.Level) bool {
+	return h.next.Enabled(ctx, lvl)
+}
+
+func (h *logfmt) WithAttrs(attrs []slog.Attr) slog.Handler {
+	return &logfmt{
+		buf:  bytes.NewBuffer([]byte{}),
+		next: h.next.WithAttrs(slices.Clone(attrs)),
+		txt:  h.txt.WithAttrs(slices.Clone(attrs)),
+	}
+}
+
+func (h *logfmt) WithGroup(g string) slog.Handler {
+	if g == "" {
+		return h
+	}
+	return &logfmt{
+		buf:  bytes.NewBuffer([]byte{}),
+		next: h.next.WithGroup(g),
+		txt:  h.txt.WithGroup(g),
+	}
+}
+
+func (h *logfmt) Handle(ctx context.Context, r slog.Record) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	if h.buf.Len() > 0 {
+		panic("buffer wasn't empty")
+	}
+
+	h.txt.Handle(ctx, r)
+	r.Message = h.buf.String()
+	r.Message = strings.TrimSuffix(r.Message, "\n")
+	h.buf.Reset()
+
+	return h.next.Handle(ctx, r)
+}