Perfetto tracing for /ok. Header parsing not complete

src/http_handler.cpp

@@ -1,5 +1,6 @@
 #include "http_handler.hpp"
 #include "arena_allocator.hpp"
+#include "perfetto_categories.hpp"
 #include <cstring>
 #include <string>
 #include <strings.h>
@@ -213,6 +214,8 @@ void HttpHandler::handleGetMetrics(Connection &conn,
 
 void HttpHandler::handleGetOk(Connection &conn,
                               const HttpConnectionState &state) {
+  TRACE_EVENT("http", "GET /ok", perfetto::Flow::Global(state.request_id));
+
   sendResponse(conn, 200, "text/plain", "OK", state.connection_close);
 }
 
@@ -254,6 +257,8 @@ void HttpHandler::sendResponse(Connection &conn, int status_code,
     break;
   }
 
+  auto *state = static_cast<HttpConnectionState *>(conn.user_data);
+
   response += "\r\n";
   response += "Content-Type: ";
   response += content_type;
@@ -261,6 +266,9 @@ void HttpHandler::sendResponse(Connection &conn, int status_code,
   response += "Content-Length: ";
   response += std::to_string(body.size());
   response += "\r\n";
+  response += "X-Response-ID: ";
+  response += std::to_string(state->request_id);
+  response += "\r\n";
 
   if (close_connection) {
     response += "Connection: close\r\n";
@@ -322,6 +330,20 @@ int HttpHandler::onHeaderValue(llhttp_t *parser, const char *at,
     }
   }
 
+  // Check for X-Request-Id header
+  if (state->current_header_field.size() == 12 &&
+      strncasecmp(state->current_header_field.data(), "x-request-id", 12) ==
+          0) {
+    uint64_t id = 0;
+    for (int i = 0; i < int(length); ++i) {
+      auto c = at[i];
+      if (c >= '0' && c <= '9') {
+        id = id * 10 + (c - '0');
+      }
+    }
+    state->request_id = id;
+  }
+
   return 0;
 }
 
@@ -348,4 +370,4 @@ int HttpHandler::onMessageComplete(llhttp_t *parser) {
   auto *state = static_cast<HttpConnectionState *>(parser->data);
   state->message_complete = true;
   return 0;
-}
+}

src/http_handler.hpp

@@ -42,6 +42,7 @@ struct HttpConnectionState {
   bool connection_close = false; // Client requested connection close
   HttpRoute route = HttpRoute::NotFound;
   std::string_view current_header_field; // Current header being parsed
+  uint64_t request_id = 0;               // X-Request-Id header value
 
   explicit HttpConnectionState(ArenaAllocator &arena);
 };
@@ -95,4 +96,4 @@ private:
   static void sendErrorResponse(Connection &conn, int status_code,
                                 std::string_view message,
                                 bool close_connection = false);
-};
+};

src/main.cpp

@@ -2,11 +2,14 @@
 #include "connection.hpp"
 #include "connection_handler.hpp"
 #include "http_handler.hpp"
+#include "perfetto_categories.hpp"
 #include "server.hpp"
 #include <atomic>
 #include <csignal>
 #include <iostream>
 
+PERFETTO_TRACK_EVENT_STATIC_STORAGE();
+
 // TODO this should be scoped to a particular Server, and it's definition should
 // be in server.cpp or connection.cpp
 std::atomic<int> activeConnections{0};
@@ -41,6 +44,13 @@ void print_help(const char *program_name) {
 }
 
 int main(int argc, char *argv[]) {
+#if ENABLE_PERFETTO
+  perfetto::TracingInitArgs args;
+  args.backends |= perfetto::kSystemBackend;
+  perfetto::Tracing::Initialize(args);
+  perfetto::TrackEvent::Register();
+#endif
+
   std::string config_file = "config.toml";
 
   // Parse command line arguments