nghttpx: Return error when downstream HTTP/1 connection attempt failed

integration-tests/nghttpx_test.go

@@ -69,6 +69,25 @@ func TestH1H1MultipleRequestCL(t *testing.T) {
 	}
 }
 
+func TestH1H1ConnectFailure(t *testing.T) {
+	st := newServerTester(nil, t, noopHandler)
+	defer st.Close()
+
+	// shutdown backend server to simulate backend connect failure
+	st.ts.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1ConnectFailure",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	want := 502
+	if got := res.status; got != want {
+		t.Errorf("status: %v; want %v", got, want)
+	}
+}
+
 func TestH2H1PlainGET(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
 	defer st.Close()
@@ -305,6 +324,25 @@ func TestH2H1InvalidRequestCL(t *testing.T) {
 	}
 }
 
+func TestH2H1ConnectFailure(t *testing.T) {
+	st := newServerTester(nil, t, noopHandler)
+	defer st.Close()
+
+	// shutdown backend server to simulate backend connect failure
+	st.ts.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1ConnectFailure",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+	want := 502
+	if got := res.status; got != want {
+		t.Errorf("status: %v; want %v", got, want)
+	}
+}
+
 func TestH2H2MultipleResponseCL(t *testing.T) {
 	st := newServerTester([]string{"--http2-bridge"}, t, func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Add("content-length", "1")

src/shrpx_http_downstream_connection.cc

@@ -95,7 +95,9 @@ void connectcb(struct ev_loop *loop, ev_io *w, int revents) {
   auto upstream = downstream->get_upstream();
   auto handler = upstream->get_client_handler();
   if (dconn->on_connect() != 0) {
-    delete handler;
+    if (upstream->downstream_error(dconn, Downstream::EVENT_ERROR) != 0) {
+      delete handler;
+    }
     return;
   }
   writecb(loop, w, revents);
@@ -747,6 +749,9 @@ end:
 
 int HttpDownstreamConnection::on_connect() {
   if (!util::check_socket_connected(fd_)) {
+    if (LOG_ENABLED(INFO)) {
+      DLOG(INFO, this) << "downstream connect failed";
+    }
     return -1;
   }
 

src/shrpx_https_upstream.cc

@@ -560,6 +560,8 @@ int HttpsUpstream::downstream_error(DownstreamConnection *dconn, int events) {
     return -1;
   }
 
+  handler_->set_should_close_after_write(true);
+
   unsigned int status;
   if (events & Downstream::EVENT_TIMEOUT) {
     status = 504;