Add telemetry

internal/telemetry/logbridge.go

@@ -0,0 +1,81 @@
+package telemetry
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	otellog "go.opentelemetry.io/otel/log"
+	sdklog "go.opentelemetry.io/otel/sdk/log"
+)
+
+// LogBridge implements io.Writer and forwards zerolog JSON lines to the
+// OTel LoggerProvider. It is used as an extra writer in zerolog's MultiWriter
+// so that logs go to both file and OTLP.
+type LogBridge struct {
+	provider *sdklog.LoggerProvider
+}
+
+func (b *LogBridge) Write(p []byte) (n int, err error) {
+	var entry map[string]interface{}
+	if err := json.Unmarshal(p, &entry); err != nil {
+		return len(p), nil // skip malformed lines
+	}
+
+	logger := b.provider.Logger("zerolog")
+
+	var rec otellog.Record
+	rec.SetTimestamp(time.Now())
+
+	if msg, ok := entry["message"].(string); ok {
+		rec.SetBody(otellog.StringValue(msg))
+	}
+
+	if lvl, ok := entry["level"].(string); ok {
+		rec.SetSeverity(mapSeverity(lvl))
+	}
+
+	// Forward all fields as attributes
+	attrs := make([]otellog.KeyValue, 0, len(entry))
+	for k, v := range entry {
+		if k == "message" || k == "level" || k == "time" {
+			continue
+		}
+		switch val := v.(type) {
+		case string:
+			attrs = append(attrs, otellog.String(k, val))
+		case float64:
+			attrs = append(attrs, otellog.Float64(k, val))
+		case bool:
+			attrs = append(attrs, otellog.Bool(k, val))
+		default:
+			b, _ := json.Marshal(val)
+			attrs = append(attrs, otellog.String(k, string(b)))
+		}
+	}
+	rec.AddAttributes(attrs...)
+
+	logger.Emit(context.Background(), rec)
+	return len(p), nil
+}
+
+func mapSeverity(level string) otellog.Severity {
+	switch level {
+	case "trace":
+		return otellog.SeverityTrace
+	case "debug":
+		return otellog.SeverityDebug
+	case "info":
+		return otellog.SeverityInfo
+	case "warn", "warning":
+		return otellog.SeverityWarn
+	case "error":
+		return otellog.SeverityError
+	case "fatal":
+		return otellog.SeverityFatal
+	case "panic":
+		return otellog.SeverityFatal2
+	default:
+		return otellog.SeverityInfo
+	}
+}