improve performance for unset values and add performance checker example

Author: Mike Prosser

examples/performance_checker/README.md

@@ -0,0 +1,18 @@
+# Performance checker Example
+
+This example demonstrates using nipanel with Streamlit to display a dynamic sine wave using the `streamlit-echarts` library.
+
+## Features
+
+- Generates sine wave data with varying frequency
+- Displays the data in an chart
+- Updates rapidly
+- Shows timing information
+
+### Required Software
+
+- Python 3.9 or later
+
+### Usage
+
+Run `poetry run python examples/performance_checker/performance_checker.py`

examples/performance_checker/performance_checker.py

@@ -0,0 +1,36 @@
+"""Example of using nipanel to display a sine wave graph using st_echarts."""
+
+import math
+import time
+from pathlib import Path
+
+import numpy as np
+
+import nipanel
+
+
+panel_script_path = Path(__file__).with_name("performance_checker_panel.py")
+panel = nipanel.create_panel(panel_script_path)
+
+amplitude = 1.0
+frequency = 1.0
+num_points = 1000
+try:
+    print(f"Panel URL: {panel.panel_url}")
+    print("Press Ctrl+C to exit")
+
+    # Generate and update the sine wave data as fast as possible
+    while True:
+        time_points = np.linspace(0, num_points, num_points)
+        sine_values = amplitude * np.sin(frequency * time_points)
+
+        panel.set_value("time_points", time_points.tolist())
+        panel.set_value("sine_values", sine_values.tolist())
+        panel.set_value("amplitude", amplitude)
+        panel.set_value("frequency", frequency)
+
+        # Slowly vary the frequency for a more dynamic visualization
+        frequency = 1.0 + 0.5 * math.sin(time.time() / 5.0)
+
+except KeyboardInterrupt:
+    print("Exiting...")

examples/performance_checker/performance_checker_panel.py

@@ -0,0 +1,118 @@
+"""A Streamlit visualization panel for the perf_check.py example script."""
+
+import statistics
+import time
+
+import streamlit as st
+from streamlit_echarts import st_echarts
+
+import nipanel
+
+
+def measure_get_value_time(panel, value_id, default_value=None):
+    """Measure the time it takes to get a value from the panel.
+
+    Args:
+        panel: The panel accessor object
+        value_id: The ID of the value to get
+        default_value: Default value if the value is not found
+
+    Returns:
+        A tuple of (value, time_ms) where time_ms is the time in milliseconds
+    """
+    start_time = time.time()
+    value = panel.get_value(value_id, default_value)
+    end_time = time.time()
+    time_ms = (end_time - start_time) * 1000
+    return value, time_ms
+
+
+st.set_page_config(page_title="Performance Checker Example", page_icon="📈", layout="wide")
+st.title("Performance Checker Example")
+
+# Initialize refresh history list if it doesn't exist
+if "refresh_history" not in st.session_state:
+    st.session_state.refresh_history = []
+
+# Store current timestamp and calculate time since last refresh
+current_time = time.time()
+if "last_refresh_time" not in st.session_state:
+    st.session_state.last_refresh_time = current_time
+    time_since_last_refresh = 0.0
+else:
+    time_since_last_refresh = (current_time - st.session_state.last_refresh_time) * 1000
+    st.session_state.last_refresh_time = current_time
+
+    # Store the last 10 refresh times
+    st.session_state.refresh_history.append(time_since_last_refresh)
+    if len(st.session_state.refresh_history) > 10:
+        st.session_state.refresh_history.pop(0)
+
+panel = nipanel.get_panel_accessor()
+
+# Measure time to get each value
+time_points, time_points_ms = measure_get_value_time(panel, "time_points", [0.0])
+sine_values, sine_values_ms = measure_get_value_time(panel, "sine_values", [0.0])
+amplitude, amplitude_ms = measure_get_value_time(panel, "amplitude", 1.0)
+frequency, frequency_ms = measure_get_value_time(panel, "frequency", 1.0)
+unset_value, unset_value_ms = measure_get_value_time(panel, "unset_value", "default")
+
+if st.session_state.refresh_history:
+    history = st.session_state.refresh_history
+else:
+    history = []
+
+# Calculate statistics
+min_time = min(history) if history else 0
+max_time = max(history) if history else 0
+avg_time = statistics.mean(history) if history else 0
+
+# Prepare data for echarts
+data = [{"value": [x, y]} for x, y in zip(time_points, sine_values)]
+
+# Configure the chart options
+options = {
+    "animation": False,  # Disable animation for smoother updates
+    "title": {"text": "Sine Wave"},
+    "tooltip": {"trigger": "axis"},
+    "xAxis": {"type": "value", "name": "Time (s)", "nameLocation": "middle", "nameGap": 30},
+    "yAxis": {
+        "type": "value",
+        "name": "Amplitude",
+        "nameLocation": "middle",
+        "nameGap": 30,
+    },
+    "series": [
+        {
+            "data": data,
+            "type": "line",
+            "showSymbol": True,
+            "smooth": True,
+            "lineStyle": {"width": 2, "color": "#1f77b4"},
+            "areaStyle": {"color": "#1f77b4", "opacity": 0.3},
+            "name": "Sine Wave",
+        }
+    ],
+}
+
+# Display the chart
+st_echarts(options=options, height="400px", key="graph")
+
+# Create columns for metrics
+col1, col2, col3, col4 = st.columns(4)
+with col1:
+    st.metric("Amplitude", f"{amplitude:.2f}")
+    st.metric("Frequency", f"{frequency:.2f} Hz")
+with col2:
+    st.metric("Refresh Time", f"{time_since_last_refresh:.1f} ms")
+    st.metric("Min Refresh Time", f"{min_time:.1f} ms")
+    st.metric("Max Refresh Time", f"{max_time:.1f} ms")
+    st.metric("Avg Refresh Time", f"{avg_time:.1f} ms")
+
+with col3:
+    st.metric("get time_points", f"{time_points_ms:.1f} ms")
+    st.metric("get sine_values", f"{sine_values_ms:.1f} ms")
+    st.metric("get amplitude", f"{amplitude_ms:.1f} ms")
+    st.metric("get frequency", f"{frequency_ms:.1f} ms")
+with col4:
+    st.metric("get unset_value", f"{unset_value_ms:.1f} ms")

protos/ni/pythonpanel/v1/python_panel_service.proto

@@ -34,7 +34,6 @@ service PythonPanelService {
   // Get a value for a control on the panel
   // Status Codes for errors:
   // - INVALID_ARGUMENT: The specified identifier contains invalid characters. Only alphanumeric characters and underscores are allowed.
-  // - NOT_FOUND: The value with the specified identifier was not found
   rpc GetValue(GetValueRequest) returns (GetValueResponse);
 
   // Set a value for a control on the panel
@@ -99,7 +98,7 @@ message GetValueRequest {
 
 message GetValueResponse {
   // The value
-  google.protobuf.Any value = 1;
+  optional google.protobuf.Any value = 1;
 }
 
 message SetValueRequest {

src/ni/pythonpanel/v1/python_panel_service_pb2.py

@@ -171,8 +171,9 @@ class GetValueResponse(google.protobuf.message.Message):
         *,
         value: google.protobuf.any_pb2.Any | None = ...,
     ) -> None: ...
-    def HasField(self, field_name: typing.Literal["value", b"value"]) -> builtins.bool: ...
-    def ClearField(self, field_name: typing.Literal["value", b"value"]) -> None: ...
+    def HasField(self, field_name: typing.Literal["_value", b"_value", "value", b"value"]) -> builtins.bool: ...
+    def ClearField(self, field_name: typing.Literal["_value", b"_value", "value", b"value"]) -> None: ...
+    def WhichOneof(self, oneof_group: typing.Literal["_value", b"_value"]) -> typing.Literal["value"] | None: ...
 
 global___GetValueResponse = GetValueResponse
 

src/ni/pythonpanel/v1/python_panel_service_pb2.pyi

@@ -77,7 +77,6 @@ def GetValue(self, request, context):
         """Get a value for a control on the panel
         Status Codes for errors:
         - INVALID_ARGUMENT: The specified identifier contains invalid characters. Only alphanumeric characters and underscores are allowed.
-        - NOT_FOUND: The value with the specified identifier was not found
         """
         context.set_code(grpc.StatusCode.UNIMPLEMENTED)
         context.set_details('Method not implemented!')

src/ni/pythonpanel/v1/python_panel_service_pb2_grpc.py

@@ -55,7 +55,6 @@ class PythonPanelServiceStub:
     """Get a value for a control on the panel
     Status Codes for errors:
     - INVALID_ARGUMENT: The specified identifier contains invalid characters. Only alphanumeric characters and underscores are allowed.
-    - NOT_FOUND: The value with the specified identifier was not found
     """
 
     SetValue: grpc.UnaryUnaryMultiCallable[
@@ -104,7 +103,6 @@ class PythonPanelServiceAsyncStub:
     """Get a value for a control on the panel
     Status Codes for errors:
     - INVALID_ARGUMENT: The specified identifier contains invalid characters. Only alphanumeric characters and underscores are allowed.
-    - NOT_FOUND: The value with the specified identifier was not found
     """
 
     SetValue: grpc.aio.UnaryUnaryMultiCallable[
@@ -161,7 +159,6 @@ class PythonPanelServiceServicer(metaclass=abc.ABCMeta):
         """Get a value for a control on the panel
         Status Codes for errors:
         - INVALID_ARGUMENT: The specified identifier contains invalid characters. Only alphanumeric characters and underscores are allowed.
-        - NOT_FOUND: The value with the specified identifier was not found
         """
 
     @abc.abstractmethod

src/ni/pythonpanel/v1/python_panel_service_pb2_grpc.pyi

@@ -116,20 +116,23 @@ def set_value(self, panel_id: str, value_id: str, value: object, notify: bool) -
         )
         self._invoke_with_retry(self._get_stub().SetValue, set_value_request)
 
-    def get_value(self, panel_id: str, value_id: str) -> object:
+    def get_value(self, panel_id: str, value_id: str) -> tuple[bool, object]:
         """Get the value for the control with value_id.
 
         Args:
             panel_id: The ID of the panel.
             value_id: The ID of the control.
 
         Returns:
-            The value.
+            A tuple containing a boolean indicating whether the value was successfully retrieved and
+            the value itself (or None if not present).
         """
         get_value_request = GetValueRequest(panel_id=panel_id, value_id=value_id)
         response = self._invoke_with_retry(self._get_stub().GetValue, get_value_request)
-        the_value = from_any(response.value)
-        return the_value
+        if response.HasField("value"):
+            return True, from_any(response.value)
+        else:
+            return False, None
 
     def _get_stub(self) -> PythonPanelServiceStub:
         if self._stub is None:

src/nipanel/_panel_client.py

@@ -60,17 +60,15 @@ def get_value(self, value_id: str, default_value: _T | None = None) -> _T | obje
         Returns:
             The value, or the default value if not set
         """
-        try:
-            value = self._panel_client.get_value(self._panel_id, value_id)
-            if default_value is not None and not isinstance(value, type(default_value)):
-                raise TypeError("Value type does not match default value type.")
-            return value
-
-        except grpc.RpcError as e:
-            if e.code() == grpc.StatusCode.NOT_FOUND and default_value is not None:
+        found, value = self._panel_client.get_value(self._panel_id, value_id)
+        if not found:
+            if default_value is not None:
                 return default_value
-            else:
-                raise e
+            raise KeyError(f"Value with id '{value_id}' not found on panel '{self._panel_id}'.")
+
+        if default_value is not None and not isinstance(value, type(default_value)):
+            raise TypeError("Value type does not match default value type.")
+        return value
 
     def set_value(self, value_id: str, value: object) -> None:
         """Set the value for a control on the panel.