break apart the ever-growing owrx/source.py

owrx/cpu.py

@@ -0,0 +1,73 @@
+import threading
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class CpuUsageThread(threading.Thread):
+    sharedInstance = None
+
+    @staticmethod
+    def getSharedInstance():
+        if CpuUsageThread.sharedInstance is None:
+            CpuUsageThread.sharedInstance = CpuUsageThread()
+        return CpuUsageThread.sharedInstance
+
+    def __init__(self):
+        self.clients = []
+        self.doRun = True
+        self.last_worktime = 0
+        self.last_idletime = 0
+        self.endEvent = threading.Event()
+        super().__init__()
+
+    def run(self):
+        while self.doRun:
+            try:
+                cpu_usage = self.get_cpu_usage()
+            except:
+                cpu_usage = 0
+            for c in self.clients:
+                c.write_cpu_usage(cpu_usage)
+            self.endEvent.wait(timeout=3)
+        logger.debug("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)
+        if not self.is_alive():
+            self.start()
+
+    def remove_client(self, c):
+        try:
+            self.clients.remove(c)
+        except ValueError:
+            pass
+        if not self.clients:
+            self.shutdown()
+
+    def shutdown(self):
+        CpuUsageThread.sharedInstance = None
+        self.doRun = False
+        self.endEvent.set()