Support non-default ports for the Discovery Service (#116)

* Resolve the discovery service and use it as the base URL for the refresh component
* Use the resolved URL when initializing the refresh component

Author: jfriedri-ni

src/nipanel/_streamlit_constants.py

@@ -1,2 +1 @@
 STREAMLIT_PYTHON_PANEL_SERVICE = "ni.pythonpanel.v1.PythonPanelService"
-STREAMLIT_REFRESH_COMPONENT_URL = "http://localhost:42001/panel-service/refresh"

src/nipanel/streamlit_refresh/__init__.py

@@ -1,17 +1,41 @@
 """Initializes a refresh component for Streamlit."""
 
-from typing import Any
+from __future__ import annotations
 
-import streamlit.components.v1 as components
+import threading
 
-from nipanel._streamlit_constants import STREAMLIT_REFRESH_COMPONENT_URL
+from ni_measurement_plugin_sdk_service.discovery import DiscoveryClient
+from ni_measurement_plugin_sdk_service.grpc.channelpool import GrpcChannelPool
+from streamlit.components.v1 import declare_component
+from streamlit.components.v1.custom_component import CustomComponent
 
 
-def initialize_refresh_component(panel_id: str) -> Any:
+_grpc_client_lock = threading.RLock()
+_panel_service_proxy_location: str | None = None
+
+
+def initialize_refresh_component(panel_id: str) -> CustomComponent:
     """Initialize a refresh component to the Streamlit app."""
-    _refresh_component_func = components.declare_component(
+    proxy_base_address = _get_or_resolve_proxy()
+    component_url = f"http://{proxy_base_address}/panel-service/refresh/{panel_id}"
+    _refresh_component_func = declare_component(
         "panelRefreshComponent",
-        url=f"{STREAMLIT_REFRESH_COMPONENT_URL}/{panel_id}",
+        url=component_url,
     )
 
     return _refresh_component_func
+
+
+def _get_or_resolve_proxy() -> str:
+    with _grpc_client_lock:
+        global _panel_service_proxy_location
+        if _panel_service_proxy_location is None:
+            with GrpcChannelPool() as grpc_channel_pool:
+                discovery_client = DiscoveryClient(grpc_channel_pool=grpc_channel_pool)
+                service_location = discovery_client.resolve_service(
+                    provided_interface="ni.http1.proxy",
+                    service_class="",
+                )
+                _panel_service_proxy_location = service_location.insecure_address
+
+        return _panel_service_proxy_location