feat: harden sessions and track downstream acknowledgements

gateway/internal/inbound/server_test.go

@@ -100,6 +100,7 @@ func TestInboundServerAuthenticatesAndSubmits(t *testing.T) {
 	var gotAuth authRequest
 	var gotSubmit submitRequest
 	connectionEvents := make(chan downstreamConnectionEvent, 8)
+	acknowledgements := make(chan map[string]any, 1)
 	api := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		switch r.URL.Path {
 		case "/api/gateway/events/inbound/authenticate":
@@ -121,6 +122,15 @@ func TestInboundServerAuthenticatesAndSubmits(t *testing.T) {
 			}
 			connectionEvents <- event
 			w.WriteHeader(http.StatusOK)
+		case "/api/gateway/events/downstream/sent":
+			w.WriteHeader(http.StatusOK)
+		case "/api/gateway/events/downstream/acknowledged":
+			var event map[string]any
+			if err := json.NewDecoder(r.Body).Decode(&event); err != nil {
+				t.Fatalf("decode acknowledgement: %v", err)
+			}
+			acknowledgements <- event
+			w.WriteHeader(http.StatusOK)
 		default:
 			t.Fatalf("unexpected api path: %s", r.URL.Path)
 		}
@@ -176,14 +186,15 @@ func TestInboundServerAuthenticatesAndSubmits(t *testing.T) {
 	if rsp.Result != 0 || rsp.MsgId == 0 {
 		t.Fatalf("unexpected submit response: %+v", rsp)
 	}
-	delivered, err := PushReceipt(DownstreamReceipt{
+	sendResult, err := PushReceiptWithResult(DownstreamReceipt{
+		DeliveryID:    "delivery-1",
 		MessageID:     "MSG-1",
 		PhoneNumber:   "13500002696",
 		ReceiptStatus: "delivered",
 		DeliveredAt:   time.Now().UTC().Format(time.RFC3339Nano),
 	})
-	if err != nil || !delivered {
-		t.Fatalf("push receipt delivered=%v err=%v", delivered, err)
+	if err != nil || !sendResult.Sent {
+		t.Fatalf("push receipt sent=%v err=%v", sendResult.Sent, err)
 	}
 	deliver := recvDeliver(t, client)
 	if deliver.RegisterDelivery != 1 {
@@ -196,6 +207,17 @@ func TestInboundServerAuthenticatesAndSubmits(t *testing.T) {
 	if receipt.Stat != "DELIVRD" || receipt.DestTerminalId != "13500002696" {
 		t.Fatalf("unexpected pushed receipt: %+v", receipt)
 	}
+	if err := client.SendRspPkt(&cmpp.Cmpp3DeliverRspPkt{MsgId: deliver.MsgId, Result: 0}, deliver.SeqId); err != nil {
+		t.Fatalf("send deliver response: %v", err)
+	}
+	select {
+	case event := <-acknowledgements:
+		if event["id"] != "delivery-1" || event["result"] != float64(0) {
+			t.Fatalf("unexpected acknowledgement callback: %+v", event)
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("expected downstream acknowledgement callback")
+	}
 	if gotAuth.Account != account || gotAuth.AuthSource == "" || gotAuth.RemoteIP == "" {
 		t.Fatalf("unexpected auth payload: %+v", gotAuth)
 	}
@@ -537,6 +559,50 @@ func TestRememberAndForgetAccountUpdatesPresenceStore(t *testing.T) {
 	}
 }
 
+func TestDownstreamDeliveryRequiresAcknowledgement(t *testing.T) {
+	resetDownstreamRegistry()
+	defer resetDownstreamRegistry()
+
+	events := make(chan downstreamDeliveryLifecycleEvent, 1)
+	conn := &cmpp.Conn{}
+	session := &downstreamSession{
+		conn: conn, connectionID: "conn-1",
+		deliveryReport: func(event downstreamDeliveryLifecycleEvent) { events <- event },
+	}
+	registerDownstreamAck(session, "delivery-1", 37, 9016479179509871733, time.Now().Add(time.Second))
+	handleDownstreamAcknowledgement(conn, 37, 9016479179509871733, 0, log.Default())
+
+	select {
+	case event := <-events:
+		if event.Kind != "acknowledged" || event.DeliveryID != "delivery-1" || event.Result != 0 || event.SequenceID != 37 {
+			t.Fatalf("unexpected acknowledgement event: %+v", event)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting acknowledgement event")
+	}
+}
+
+func TestDownstreamDeliveryReportsAckTimeout(t *testing.T) {
+	resetDownstreamRegistry()
+	defer resetDownstreamRegistry()
+
+	events := make(chan downstreamDeliveryLifecycleEvent, 1)
+	session := &downstreamSession{
+		conn: &cmpp.Conn{}, connectionID: "conn-1",
+		deliveryReport: func(event downstreamDeliveryLifecycleEvent) { events <- event },
+	}
+	registerDownstreamAck(session, "delivery-timeout", 38, 9017467844344255865, time.Now().Add(20*time.Millisecond))
+
+	select {
+	case event := <-events:
+		if event.Kind != "failed" || event.FailureType != "ack_timeout" || event.DeliveryID != "delivery-timeout" {
+			t.Fatalf("unexpected timeout event: %+v", event)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting acknowledgement timeout")
+	}
+}
+
 func recvDeliver(t *testing.T, client *cmpp.Client) *cmpp.Cmpp3DeliverReqPkt {
 	t.Helper()
 	deadline := time.Now().Add(2 * time.Second)
@@ -575,6 +641,14 @@ func resetDownstreamRegistry() {
 	downstreamRegistry.byAccount = make(map[string]*downstreamSession)
 	downstreamRegistry.byMessageID = make(map[string]*downstreamSession)
 	downstreamRegistry.byConn = make(map[*cmpp.Conn]*downstreamSession)
+	downstreamAckRegistry.Lock()
+	for _, tracker := range downstreamAckRegistry.items {
+		if tracker.timer != nil {
+			tracker.timer.Stop()
+		}
+	}
+	downstreamAckRegistry.items = make(map[string]*downstreamAckTracker)
+	downstreamAckRegistry.Unlock()
 }
 
 func reserveTCPAddr(t *testing.T) string {