add ClientMessageManager.set_server_keyframe_id and RemoteGuiInput.po…

…p_recent_server_keyframe_id to help the server measure client latency (#1796)

habitat-hitl/habitat_hitl/_internal/networking/keyframe_utils.py

@@ -95,18 +95,12 @@ def ensure_dict(keyframe, key):
 
     if "message" in inc_keyframe:
         inc_message = inc_keyframe["message"]
-        # add/update these messages
-        for message_key in [
-            "teleportAvatarBasePosition",
-            "sceneChanged",
-            "navmeshVertices",
-            "isAppReady",
-        ]:
-            if message_key in inc_message:
-                ensure_dict(consolidated_keyframe, "message")
-                consolidated_keyframe["message"][message_key] = inc_message[
-                    message_key
-                ]
+        # add/update all messages
+        for message_key in inc_message:
+            ensure_dict(consolidated_keyframe, "message")
+            consolidated_keyframe["message"][message_key] = inc_message[
+                message_key
+            ]
 
     # todo: lights, userTransforms
 

habitat-hitl/habitat_hitl/core/client_message_manager.py

@@ -58,6 +58,9 @@ def signal_app_ready(self):
         """
         self._message["isAppReady"] = True
 
+    def set_server_keyframe_id(self, keyframe_id):
+        self._message["serverKeyframeId"] = keyframe_id
+
     def update_navmesh_triangles(self, triangle_vertices):
         r"""
         Send a navmesh. triangle_vertices should be a list of vertices, 3 per triangle.

habitat-hitl/habitat_hitl/core/remote_gui_input.py

@@ -12,6 +12,7 @@
 from habitat_hitl.core.gui_input import GuiInput
 
 
+# todo: rename to RemoteClientState
 class RemoteGuiInput:
     def __init__(self, interprocess_record, debug_line_render):
         self._recent_client_states = []
@@ -44,6 +45,23 @@ def get_history_timestep(self):
     def get_connection_params(self):
         return self._connection_params
 
+    def pop_recent_server_keyframe_id(self):
+        """
+        Removes and returns ("pops") the recentServerKeyframeId included in the latest client state.
+
+        The removal behavior here is to help user code by only returning a keyframe ID when a new (unseen) one is available.
+        """
+        if len(self._recent_client_states) == 0:
+            return None
+
+        latest_client_state = self._recent_client_states[0]
+        if "recentServerKeyframeId" not in latest_client_state:
+            return None
+
+        retval = int(latest_client_state["recentServerKeyframeId"])
+        del latest_client_state["recentServerKeyframeId"]
+        return retval
+
     def get_head_pose(self, history_index=0):
         if history_index >= len(self._recent_client_states):
             return None, None

habitat-hitl/habitat_hitl/scripts/stub_client.html

@@ -39,6 +39,8 @@
             var url = 'ws://' + ip + ':' + port;
             document.getElementById('serverUrl').textContent = 'Server URL: ' + url;
             ws = new WebSocket(url);
+            var sendIntervalId = null;  // Variable to hold the ID of the interval
+            var recentServerKeyframeId = null;
 
             ws.onopen = function() {
                 document.getElementById('status').textContent = 'Connected';
@@ -48,6 +50,18 @@
                 document.getElementById('serverPort').disabled = true;
                 document.getElementById('sendButton').disabled = false;
                 ws.send('client ready!');  // Send "client ready!" to the server
+
+                // Start sending messages at 10 Hz
+                sendIntervalId = setInterval(function() {
+                        var dict = {};  // Create an empty JavaScript object
+
+                        // Our stub client only sends recentServerKeyframeId. It doesn't send local GUI input or other client state.
+                        if (recentServerKeyframeId != null) {
+                            dict["recentServerKeyframeId"] = recentServerKeyframeId;
+                        }
+                        var message = JSON.stringify(dict);  // Convert the object to a JSON string
+                        ws.send(message);  // Send the JSON string
+                    }, 100);  // Repeat every 100 milliseconds
             };
 
             ws.onclose = function() {
@@ -57,10 +71,34 @@
                 document.getElementById('serverIp').disabled = false;
                 document.getElementById('serverPort').disabled = false;
                 document.getElementById('sendButton').disabled = true;
+
+                if (sendIntervalId) {
+                    clearInterval(sendIntervalId);
+                    sendIntervalId = null;
+                }
+                recentServerKeyframeId = null;
+
             };
 
             ws.onmessage = function() {
                 messageCount++;
+
+                var message = event.data;
+                var dict = JSON.parse(message);
+
+                // parse the latest serverKeyframeId from received keyframes
+                if ("keyframes" in dict) {
+                    keyframes = dict["keyframes"]
+                    if (keyframes.length) {
+                        keyframe = keyframes[keyframes.length - 1];
+                        if ("message" in keyframe) {
+                            message = keyframe["message"]
+                            if ("serverKeyframeId" in message) {
+                                recentServerKeyframeId = message["serverKeyframeId"];
+                            }
+                        }
+                    }
+                }
             };
         }