FrontendService: Add tracing and logging middleware (#107956)

* FrontendService: Add tracing and logging middleware

* tests!

* middleware tests

* context middleware test

* revert http_server back to previous version

* fix lint

* fix test

* use http.NotFound instead of custom http handler

* use existing tracer for package

* use otel/trace.Tracer in request_tracing middleware

* tidy up tracing in contextMiddleware

* fix 404 test

* remove spans from contextMiddleware

* comment

pkg/middleware/request_tracing.go

@@ -71,14 +71,23 @@ func RouteOperationName(req *http.Request) (string, bool) {
 	return "", false
 }
 
-func RequestTracing(tracer tracing.Tracer) web.Middleware {
+// Paths that don't need tracing spans applied to them because of the
+// little value that would provide us
+func SkipTracingPaths(req *http.Request) bool {
+	return strings.HasPrefix(req.URL.Path, "/public/") ||
+		req.URL.Path == "/robots.txt" ||
+		req.URL.Path == "/favicon.ico" ||
+		req.URL.Path == "/api/health"
+}
+
+func TraceAllPaths(req *http.Request) bool {
+	return true
+}
+
+func RequestTracing(tracer trace.Tracer, shouldTrace func(*http.Request) bool) web.Middleware {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-			// skip tracing for a few endpoints
-			if strings.HasPrefix(req.URL.Path, "/public/") ||
-				req.URL.Path == "/robots.txt" ||
-				req.URL.Path == "/favicon.ico" ||
-				req.URL.Path == "/api/health" {
+			if !shouldTrace(req) {
 				next.ServeHTTP(w, req)
 				return
 			}