moved cpu usage to a grpc call that the gui will listen to, fixed grpc stream typing to be grpc.Future, fixed pygui issue for start callback when a start fails, but there are no exceptions

daemon/core/api/grpc/client.py

@@ -467,7 +467,7 @@ class CoreGrpcClient:
         session_id: int,
         handler: Callable[[core_pb2.Event], None],
         events: List[core_pb2.Event] = None,
-    ) -> grpc.Channel:
+    ) -> grpc.Future:
         """
         Listen for session events.
 
@@ -484,7 +484,7 @@ class CoreGrpcClient:
 
     def throughputs(
         self, session_id: int, handler: Callable[[core_pb2.ThroughputsEvent], None]
-    ) -> grpc.Channel:
+    ) -> grpc.Future:
         """
         Listen for throughput events with information for interfaces and bridges.
 
@@ -498,6 +498,21 @@ class CoreGrpcClient:
         start_streamer(stream, handler)
         return stream
 
+    def cpu_usage(
+        self, delay: int, handler: Callable[[core_pb2.CpuUsageEvent], None]
+    ) -> grpc.Future:
+        """
+        Listen for cpu usage events with the given repeat delay.
+
+        :param delay: delay between receiving events
+        :param handler: handler for every event
+        :return: stream processing events, can be used to cancel stream
+        """
+        request = core_pb2.CpuUsageRequest(delay=delay)
+        stream = self.stub.CpuUsage(request)
+        start_streamer(stream, handler)
+        return stream
+
     def add_node(
         self, session_id: int, node: core_pb2.Node, source: str = None
     ) -> core_pb2.AddNodeResponse:

daemon/core/api/grpc/grpcutils.py

@@ -1,5 +1,6 @@
 import logging
 import time
+from pathlib import Path
 from typing import Any, Dict, List, Tuple, Type, Union
 
 import grpc
@@ -20,6 +21,25 @@ from core.services.coreservices import CoreService
 WORKERS = 10
 
 
+class CpuUsage:
+    def __init__(self) -> None:
+        self.stat_file: Path = Path("/proc/stat")
+        self.prev_idle: int = 0
+        self.prev_total: int = 0
+
+    def run(self) -> float:
+        lines = self.stat_file.read_text().splitlines()[0]
+        values = [int(x) for x in lines.split()[1:]]
+        idle = sum(values[3:5])
+        non_idle = sum(values[:3] + values[5:8])
+        total = idle + non_idle
+        total_diff = total - self.prev_total
+        idle_diff = idle - self.prev_idle
+        self.prev_idle = idle
+        self.prev_total = total
+        return (total_diff - idle_diff) / total_diff
+
+
 def add_node_data(node_proto: core_pb2.Node) -> Tuple[NodeTypes, int, NodeOptions]:
     """
     Convert node protobuf message to data for creating a node.

daemon/core/api/grpc/server.py

@@ -681,6 +681,15 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
             last_stats = stats
             time.sleep(delay)
 
+    def CpuUsage(
+        self, request: core_pb2.CpuUsageRequest, context: ServicerContext
+    ) -> None:
+        cpu_usage = grpcutils.CpuUsage()
+        while self._is_running(context):
+            usage = cpu_usage.run()
+            yield core_pb2.CpuUsageEvent(usage=usage)
+            time.sleep(request.delay)
+
     def AddNode(
         self, request: core_pb2.AddNodeRequest, context: ServicerContext
     ) -> core_pb2.AddNodeResponse: