add cpu usage

owrx/source.py

@@ -2,6 +2,7 @@ import subprocess
 from owrx.config import PropertyManager
 import threading
 import csdr
+import time
 
 class RtlNmuxSource(object):
     def __init__(self):
@@ -157,3 +158,62 @@ class DspManager(object):
 
     def setProperty(self, prop, value):
         self.localProps.getProperty(prop).setValue(value)
+
+class CpuUsageThread(threading.Thread):
+    sharedInstance = None
+    @staticmethod
+    def getSharedInstance():
+        if CpuUsageThread.sharedInstance is None:
+            CpuUsageThread.sharedInstance = CpuUsageThread()
+            CpuUsageThread.sharedInstance.start()
+        return CpuUsageThread.sharedInstance
+
+    def __init__(self):
+        self.clients = []
+        self.doRun = True
+        self.last_worktime = 0
+        self.last_idletime = 0
+        super().__init__()
+
+    def run(self):
+        while self.doRun:
+            time.sleep(3)
+            try:
+                cpu_usage = self.get_cpu_usage()
+            except:
+                cpu_usage = 0
+            for c in self.clients:
+                c.write_cpu_usage(cpu_usage)
+        print("cpu usage thread shut down")
+
+    def get_cpu_usage(self):
+        try:
+            f = open("/proc/stat","r")
+        except:
+            return 0 #Workaround, possibly we're on a Mac
+        line = ""
+        while not "cpu " in line: line=f.readline()
+        f.close()
+        spl = line.split(" ")
+        worktime = int(spl[2]) + int(spl[3]) + int(spl[4])
+        idletime = int(spl[5])
+        dworktime = (worktime - self.last_worktime)
+        didletime = (idletime - self.last_idletime)
+        rate = float(dworktime) / (didletime+dworktime)
+        self.last_worktime = worktime
+        self.last_idletime = idletime
+        if (self.last_worktime==0): return 0
+        return rate
+
+    def add_client(self, c):
+        self.clients.append(c)
+
+    def remove_client(self, c):
+        self.clients.remove(c)
+        if not self.clients:
+            self.shutdown()
+
+    def shutdown(self):
+        print("shutting down cpu usage thread")
+        CpuUsageThread.sharedInstance = None
+        self.doRun = False