Add Enhanced Jaeger Tracing Support (Updated)

go.mod

@@ -1,4 +1,4 @@
-module github.com/username/project
+module github.com/ajeetraina/genai-app-demo
 
 go 1.23.4
 
@@ -40,4 +40,4 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250218202821-56aae31c358a // indirect
 	google.golang.org/grpc v1.71.0 // indirect
 	google.golang.org/protobuf v1.36.5 // indirect
-)
+)

pkg/metrics/summary.go

@@ -7,7 +7,8 @@ import (
 	"sync"
 	"time"
 
-	"github.com/prometheus/client_golang/prometheus"
+	// Import only what's needed for this file
+	_ "github.com/prometheus/client_golang/prometheus" // blank import for side effects
 	"github.com/rs/zerolog/log"
 )
 

pkg/middleware/responsewriter.go

@@ -0,0 +1,30 @@
+package middleware
+
+import (
+	"net/http"
+)
+
+// responseWriterWrapper is a custom response writer that captures the status code
+type responseWriterWrapper struct {
+	w          http.ResponseWriter
+	statusCode int
+}
+
+func (rww *responseWriterWrapper) Header() http.Header {
+	return rww.w.Header()
+}
+
+func (rww *responseWriterWrapper) Write(bytes []byte) (int, error) {
+	return rww.w.Write(bytes)
+}
+
+func (rww *responseWriterWrapper) WriteHeader(statusCode int) {
+	rww.statusCode = statusCode
+	rww.w.WriteHeader(statusCode)
+}
+
+func (rww *responseWriterWrapper) Flush() {
+	if f, ok := rww.w.(http.Flusher); ok {
+		f.Flush()
+	}
+}

pkg/middleware/tracing.go

@@ -0,0 +1,64 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/ajeetraina/genai-app-demo/pkg/tracing"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// TracingMiddleware adds OpenTelemetry tracing to HTTP requests
+func TracingMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Skip tracing for metrics endpoint to avoid noise
+		if strings.HasPrefix(r.URL.Path, "/metrics") {
+			next.ServeHTTP(w, r)
+			return
+		}
+
+		// Start a new span for this request
+		ctx, span := tracing.StartSpan(r.Context(), "http_request")
+		defer span.End()
+
+		// Add request attributes to the span
+		span.SetAttributes(
+			attribute.String("http.method", r.Method),
+			attribute.String("http.url", r.URL.String()),
+			attribute.String("http.user_agent", r.UserAgent()),
+			attribute.String("http.host", r.Host),
+			attribute.String("http.scheme", getScheme(r)),
+			attribute.String("http.target", r.URL.Path),
+		)
+
+		// Wrap the response writer to capture status code
+		responseWriter := &responseWriterWrapper{w: w, statusCode: http.StatusOK}
+
+		// Call the next handler with the updated context
+		next.ServeHTTP(responseWriter, r.WithContext(ctx))
+
+		// Add response attributes
+		span.SetAttributes(attribute.Int("http.status_code", responseWriter.statusCode))
+	})
+}
+
+// Helper to determine the scheme (http vs https)
+func getScheme(r *http.Request) string {
+	if r.TLS != nil {
+		return "https"
+	}
+	if proto := r.Header.Get("X-Forwarded-Proto"); proto != "" {
+		return proto
+	}
+	if proto := r.Header.Get("X-Forwarded-Protocol"); proto != "" {
+		return proto
+	}
+	if ssl := r.Header.Get("X-Forwarded-Ssl"); ssl == "on" {
+		return "https"
+	}
+	if proto := r.Header.Get("X-Url-Scheme"); proto != "" {
+		return proto
+	}
+	return "http"
+}