nghttpx: Add --frontend-max-requests option

gennghttpxfun.py

@@ -161,6 +161,7 @@ OPTIONS = [
     "tls-min-proto-version",
     "tls-max-proto-version",
     "redirect-https-port",
+    "frontend-max-requests",
 ]
 
 LOGVARS = [

src/shrpx.cc

@@ -1448,6 +1448,7 @@ void fill_default_config(Config *config) {
   httpconf.response_header_field_buffer = 64_k;
   httpconf.max_response_header_fields = 500;
   httpconf.redirect_https_port = StringRef::from_lit("443");
+  httpconf.max_requests = std::numeric_limits<size_t>::max();
 
   auto &http2conf = config->http2;
   {
@@ -2581,6 +2582,13 @@ DNS:
               lookup.
               Default: )"
       << config->dns.max_try << R"(
+  --frontend-max-requests=<N>
+              The number  of requests that single  frontend connection
+              can process.  For HTTP/2, this  is the number of streams
+              in  one  HTTP/2 connection.   For  HTTP/1,  this is  the
+              number of keep alive requests.  This is hint to nghttpx,
+              and it  may allow additional few  requests.  The default
+              value is unlimited.
 
 Debug:
   --frontend-http2-dump-request-header=<PATH>
@@ -3266,6 +3274,8 @@ int main(int argc, char **argv) {
         {SHRPX_OPT_TLS_MAX_PROTO_VERSION.c_str(), required_argument, &flag,
          153},
         {SHRPX_OPT_REDIRECT_HTTPS_PORT.c_str(), required_argument, &flag, 154},
+        {SHRPX_OPT_FRONTEND_MAX_REQUESTS.c_str(), required_argument, &flag,
+         155},
         {nullptr, 0, nullptr, 0}};
 
     int option_index = 0;
@@ -3992,6 +4002,11 @@ int main(int argc, char **argv) {
         // --redirect-https-port
         cmdcfgs.emplace_back(SHRPX_OPT_REDIRECT_HTTPS_PORT, StringRef{optarg});
         break;
+      case 155:
+        // --frontend-max-requests
+        cmdcfgs.emplace_back(SHRPX_OPT_FRONTEND_MAX_REQUESTS,
+                             StringRef{optarg});
+        break;
       default:
         break;
       }

src/shrpx_config.cc

@@ -1817,6 +1817,11 @@ int option_lookup_token(const char *name, size_t namelen) {
         return SHRPX_OPTID_TLS_TICKET_KEY_CIPHER;
       }
       break;
+    case 's':
+      if (util::strieq_l("frontend-max-request", name, 20)) {
+        return SHRPX_OPTID_FRONTEND_MAX_REQUESTS;
+      }
+      break;
     case 't':
       if (util::strieq_l("backend-write-timeou", name, 20)) {
         return SHRPX_OPTID_BACKEND_WRITE_TIMEOUT;
@@ -3369,6 +3374,8 @@ int parse_config(Config *config, int optid, const StringRef &opt,
     config->http.redirect_https_port = optarg;
     return 0;
   }
+  case SHRPX_OPTID_FRONTEND_MAX_REQUESTS:
+    return parse_uint(&config->http.max_requests, opt, optarg);
   case SHRPX_OPTID_CONF:
     LOG(WARN) << "conf: ignored";
 

src/shrpx_config.h

@@ -333,6 +333,8 @@ constexpr auto SHRPX_OPT_TLS_MAX_PROTO_VERSION =
     StringRef::from_lit("tls-max-proto-version");
 constexpr auto SHRPX_OPT_REDIRECT_HTTPS_PORT =
     StringRef::from_lit("redirect-https-port");
+constexpr auto SHRPX_OPT_FRONTEND_MAX_REQUESTS =
+    StringRef::from_lit("frontend-max-requests");
 
 constexpr size_t SHRPX_OBFUSCATED_NODE_LENGTH = 8;
 
@@ -647,6 +649,7 @@ struct HttpConfig {
   size_t max_request_header_fields;
   size_t response_header_field_buffer;
   size_t max_response_header_fields;
+  size_t max_requests;
   bool no_via;
   bool no_location_rewrite;
   bool no_host_rewrite;
@@ -994,6 +997,7 @@ enum {
   SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_BITS,
   SHRPX_OPTID_FRONTEND_HTTP2_WINDOW_SIZE,
   SHRPX_OPTID_FRONTEND_KEEP_ALIVE_TIMEOUT,
+  SHRPX_OPTID_FRONTEND_MAX_REQUESTS,
   SHRPX_OPTID_FRONTEND_NO_TLS,
   SHRPX_OPTID_FRONTEND_READ_TIMEOUT,
   SHRPX_OPTID_FRONTEND_WRITE_TIMEOUT,

src/shrpx_http2_upstream.cc

@@ -271,16 +271,21 @@ int on_begin_headers_callback(nghttp2_session *session,
                          << frame->hd.stream_id;
   }
 
-  auto handler = upstream->get_client_handler();
+  upstream->on_start_request(frame);
 
-  auto downstream = make_unique<Downstream>(upstream, handler->get_mcpool(),
+  return 0;
+}
+} // namespace
+
+void Http2Upstream::on_start_request(const nghttp2_frame *frame) {
+  auto downstream = make_unique<Downstream>(this, handler_->get_mcpool(),
                                             frame->hd.stream_id);
-  nghttp2_session_set_stream_user_data(session, frame->hd.stream_id,
+  nghttp2_session_set_stream_user_data(session_, frame->hd.stream_id,
                                        downstream.get());
 
   downstream->reset_upstream_rtimer();
 
-  handler->repeat_read_timer();
+  handler_->repeat_read_timer();
 
   auto &req = downstream->request();
 
@@ -289,11 +294,16 @@ int on_begin_headers_callback(nghttp2_session *session,
   req.http_major = 2;
   req.http_minor = 0;
 
-  upstream->add_pending_downstream(std::move(downstream));
+  add_pending_downstream(std::move(downstream));
 
-  return 0;
+  ++num_requests_;
+
+  auto config = get_config();
+  auto &httpconf = config->http;
+  if (httpconf.max_requests <= num_requests_) {
+    start_graceful_shutdown();
+  }
 }
-} // namespace
 
 int Http2Upstream::on_request_headers(Downstream *downstream,
                                       const nghttp2_frame *frame) {
@@ -873,8 +883,6 @@ void Http2Upstream::submit_goaway() {
 }
 
 void Http2Upstream::check_shutdown() {
-  int rv;
-
   auto worker = handler_->get_worker();
 
   if (!worker->get_graceful_shutdown()) {
@@ -883,6 +891,15 @@ void Http2Upstream::check_shutdown() {
 
   ev_prepare_stop(handler_->get_loop(), &prep_);
 
+  start_graceful_shutdown();
+}
+
+void Http2Upstream::start_graceful_shutdown() {
+  int rv;
+  if (ev_is_active(&shutdown_timer_)) {
+    return;
+  }
+
   rv = nghttp2_submit_shutdown_notice(session_);
   if (rv != 0) {
     ULOG(FATAL, this) << "nghttp2_submit_shutdown_notice() failed: "
@@ -965,7 +982,8 @@ Http2Upstream::Http2Upstream(ClientHandler *handler)
                         !get_config()->http2_proxy),
       handler_(handler),
       session_(nullptr),
-      max_buffer_size_(MAX_BUFFER_SIZE) {
+      max_buffer_size_(MAX_BUFFER_SIZE),
+      num_requests_(0) {
   int rv;
 
   auto config = get_config();

src/shrpx_http2_upstream.h

@@ -111,11 +111,15 @@ public:
 
   void submit_goaway();
   void check_shutdown();
+  // Starts graceful shutdown period.
+  void start_graceful_shutdown();
 
   int prepare_push_promise(Downstream *downstream);
   int submit_push_promise(const StringRef &scheme, const StringRef &authority,
                           const StringRef &path, Downstream *downstream);
 
+  // Called when new request has started.
+  void on_start_request(const nghttp2_frame *frame);
   int on_request_headers(Downstream *downstream, const nghttp2_frame *frame);
 
   DefaultMemchunks *get_response_buf();
@@ -134,6 +138,8 @@ private:
   ClientHandler *handler_;
   nghttp2_session *session_;
   size_t max_buffer_size_;
+  // The number of requests seen so far.
+  size_t num_requests_;
   bool flow_control_;
 };
 

src/shrpx_https_upstream.cc

@@ -52,7 +52,8 @@ namespace shrpx {
 HttpsUpstream::HttpsUpstream(ClientHandler *handler)
     : handler_(handler),
       current_header_length_(0),
-      ioctrl_(handler->get_rlimit()) {
+      ioctrl_(handler->get_rlimit()),
+      num_requests_(0) {
   http_parser_init(&htp_, HTTP_REQUEST);
   htp_.data = this;
 }
@@ -63,27 +64,30 @@ void HttpsUpstream::reset_current_header_length() {
   current_header_length_ = 0;
 }
 
-namespace {
+void HttpsUpstream::on_start_request() {
-int htp_msg_begin(http_parser *htp) {
-  auto upstream = static_cast<HttpsUpstream *>(htp->data);
   if (LOG_ENABLED(INFO)) {
-    ULOG(INFO, upstream) << "HTTP request started";
+    ULOG(INFO, this) << "HTTP request started";
   }
-  upstream->reset_current_header_length();
+  reset_current_header_length();
 
-  auto handler = upstream->get_client_handler();
+  auto downstream = make_unique<Downstream>(this, handler_->get_mcpool(), 0);
 
-  auto downstream = make_unique<Downstream>(upstream, handler->get_mcpool(), 0);
+  attach_downstream(std::move(downstream));
 
-  upstream->attach_downstream(std::move(downstream));
+  auto conn = handler_->get_connection();
-
-  auto conn = handler->get_connection();
   auto &upstreamconf = get_config()->conn.upstream;
 
   conn->rt.repeat = upstreamconf.timeout.read;
 
-  handler->repeat_read_timer();
+  handler_->repeat_read_timer();
 
+  ++num_requests_;
+}
+
+namespace {
+int htp_msg_begin(http_parser *htp) {
+  auto upstream = static_cast<HttpsUpstream *>(htp->data);
+  upstream->on_start_request();
   return 0;
 }
 } // namespace
@@ -868,12 +872,14 @@ int HttpsUpstream::send_reply(Downstream *downstream, const uint8_t *body,
   auto &resp = downstream->response();
   auto &balloc = downstream->get_block_allocator();
   auto config = get_config();
+  auto &httpconf = config->http;
 
   auto connection_close = false;
 
   auto worker = handler_->get_worker();
 
-  if (worker->get_graceful_shutdown()) {
+  if (httpconf.max_requests <= num_requests_ &&
+      worker->get_graceful_shutdown()) {
     resp.fs.add_header_token(StringRef::from_lit("connection"),
                              StringRef::from_lit("close"), false,
                              http2::HD_CONNECTION);
@@ -917,8 +923,6 @@ int HttpsUpstream::send_reply(Downstream *downstream, const uint8_t *body,
     output->append("\r\n");
   }
 
-  auto &httpconf = config->http;
-
   for (auto &p : httpconf.add_response_headers) {
     output->append(p.name);
     output->append(": ");
@@ -1078,7 +1082,8 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream) {
 
   // after graceful shutdown commenced, add connection: close header
   // field.
-  if (worker->get_graceful_shutdown()) {
+  if (httpconf.max_requests <= num_requests_ ||
+      worker->get_graceful_shutdown()) {
     resp.connection_close = true;
   }
 

src/shrpx_https_upstream.h

@@ -95,12 +95,17 @@ public:
   void log_response_headers(DefaultMemchunks *buf) const;
   int redirect_to_https(Downstream *downstream);
 
+  // Called when new request has started.
+  void on_start_request();
+
 private:
   ClientHandler *handler_;
   http_parser htp_;
   size_t current_header_length_;
   std::unique_ptr<Downstream> downstream_;
   IOControl ioctrl_;
+  // The number of requests seen so far.
+  size_t num_requests_;
 };
 
 } // namespace shrpx