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:

daemon/core/gui/coreclient.py

@@ -16,6 +16,7 @@ from core.api.grpc import client
 from core.api.grpc.common_pb2 import ConfigOption
 from core.api.grpc.configservices_pb2 import ConfigService, ConfigServiceConfig
 from core.api.grpc.core_pb2 import (
+    CpuUsageEvent,
     Event,
     ExceptionEvent,
     Hook,
@@ -55,6 +56,7 @@ if TYPE_CHECKING:
     from core.gui.app import Application
 
 GUI_SOURCE = "gui"
+CPU_USAGE_DELAY = 3
 
 
 class CoreClient:
@@ -92,8 +94,9 @@ class CoreClient:
         self.hooks: Dict[str, Hook] = {}
         self.emane_config: Dict[str, ConfigOption] = {}
         self.mobility_players: Dict[int, MobilityPlayer] = {}
-        self.handling_throughputs: Optional[grpc.Channel] = None
+        self.handling_throughputs: Optional[grpc.Future] = None
-        self.handling_events: Optional[grpc.Channel] = None
+        self.handling_cpu_usage: Optional[grpc.Future] = None
+        self.handling_events: Optional[grpc.Future] = None
         self.xml_dir: Optional[str] = None
         self.xml_file: Optional[str] = None
 
@@ -111,6 +114,7 @@ class CoreClient:
                 )
                 if throughputs_enabled:
                     self.enable_throughputs()
+            self.setup_cpu_usage()
         return self._client
 
     def reset(self) -> None:
@@ -258,6 +262,20 @@ class CoreClient:
             self.handling_events.cancel()
             self.handling_events = None
 
+    def cancel_cpu_usage(self) -> None:
+        if self.handling_cpu_usage:
+            self.handling_cpu_usage.cancel()
+            self.handling_cpu_usage = None
+
+    def setup_cpu_usage(self) -> None:
+        if self.handling_cpu_usage and self.handling_cpu_usage.running():
+            return
+        if self.handling_cpu_usage:
+            self.handling_cpu_usage.cancel()
+        self.handling_cpu_usage = self._client.cpu_usage(
+            CPU_USAGE_DELAY, self.handle_cpu_event
+        )
+
     def handle_throughputs(self, event: ThroughputsEvent) -> None:
         if event.session_id != self.session_id:
             logging.warning(
@@ -269,6 +287,9 @@ class CoreClient:
         logging.debug("handling throughputs event: %s", event)
         self.app.after(0, self.app.canvas.set_throughputs, event)
 
+    def handle_cpu_event(self, event: CpuUsageEvent) -> None:
+        self.app.after(0, self.app.statusbar.set_cpu, event.usage)
+
     def handle_exception_event(self, event: ExceptionEvent) -> None:
         logging.info("exception event: %s", event)
         self.app.statusbar.add_alert(event)
@@ -479,6 +500,8 @@ class CoreClient:
         """
         try:
             self.client.connect()
+            self.setup_cpu_usage()
+
             # get service information
             response = self.client.get_services()
             for service in response.services:

daemon/core/gui/statusbar.py

@@ -1,10 +1,7 @@
 """
 status bar
 """
-import sched
 import tkinter as tk
-from pathlib import Path
-from threading import Thread
 from tkinter import ttk
 from typing import TYPE_CHECKING, List, Optional
 
@@ -16,41 +13,6 @@ if TYPE_CHECKING:
     from core.gui.app import Application
 
 
-class CpuUsage:
-    def __init__(self, statusbar: "StatusBar") -> None:
-        self.scheduler: sched.scheduler = sched.scheduler()
-        self.running: bool = False
-        self.thread: Optional[Thread] = None
-        self.prev_idle: int = 0
-        self.prev_total: int = 0
-        self.stat_file: Path = Path("/proc/stat")
-        self.statusbar: "StatusBar" = statusbar
-
-    def start(self) -> None:
-        self.running = True
-        self.thread = Thread(target=self._start, daemon=True)
-        self.thread.start()
-
-    def _start(self):
-        self.scheduler.enter(0, 0, self.run)
-        self.scheduler.run()
-
-    def run(self) -> None:
-        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
-        cpu_percent = (total_diff - idle_diff) / total_diff
-        self.statusbar.after(0, self.statusbar.set_cpu, cpu_percent)
-        self.prev_idle = idle
-        self.prev_total = total
-        if self.running:
-            self.scheduler.enter(3, 0, self.run)
-
-
 class StatusBar(ttk.Frame):
     def __init__(self, master: tk.Widget, app: "Application") -> None:
         super().__init__(master)
@@ -64,8 +26,6 @@ class StatusBar(ttk.Frame):
         self.running: bool = False
         self.core_alarms: List[ExceptionEvent] = []
         self.draw()
-        self.cpu_usage: CpuUsage = CpuUsage(self)
-        self.cpu_usage.start()
 
     def draw(self) -> None:
         self.columnconfigure(0, weight=7)

daemon/core/gui/toolbar.py

@@ -305,10 +305,11 @@ class Toolbar(ttk.Frame):
             self.set_runtime()
             self.app.core.set_metadata()
             self.app.core.show_mobility_players()
-        elif response.exceptions:
+        else:
             enable_buttons(self.design_frame, enabled=True)
-            message = "\n".join(response.exceptions)
+            if response.exceptions:
-            self.app.show_error("Start Session Error", message)
+                message = "\n".join(response.exceptions)
+                self.app.show_error("Start Session Error", message)
 
     def set_runtime(self) -> None:
         enable_buttons(self.runtime_frame, enabled=True)

daemon/proto/core/api/grpc/core.proto

@@ -51,6 +51,8 @@ service CoreApi {
     }
     rpc Throughputs (ThroughputsRequest) returns (stream ThroughputsEvent) {
     }
+    rpc CpuUsage (CpuUsageRequest) returns (stream CpuUsageEvent) {
+    }
 
     // node rpc
     rpc AddNode (AddNodeRequest) returns (AddNodeResponse) {
@@ -347,6 +349,14 @@ message ThroughputsEvent {
     repeated InterfaceThroughput iface_throughputs = 3;
 }
 
+message CpuUsageRequest {
+    int32 delay = 1;
+}
+
+message CpuUsageEvent {
+    double usage = 1;
+}
+
 message InterfaceThroughput {
     int32 node_id = 1;
     int32 iface_id = 2;