Adding server modules

util/__init__.py

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+from .serverbase import ServerBase
+from .zmqbase import ZMQBase

util/serverbase.py

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+import sys
+import signal
+import os
+import socket
+import logging
+import logging.handlers
+from logging.handlers import RotatingFileHandler
+from datetime import datetime
+import time
+
+from epics import PV
+import ZMQBase
+
+class ServerBase (ZMQBase):
+    def __init__(self, root = 'MyServer', debug = False, WDServer = '127.0.0.1', WDPort = 5678):
+
+        super(ServerBase,self).__init__(WDServer,WDPort)
+
+        self.debug = debug
+        self.root = root
+        self.suffix=''
+        if self.debug:
+            self.suffix='-SIMU'
+        self.host = socket.gethostname()
+        self.pid = os.getpid()  # process ID
+       
+        # enabling logging
+        self.logfilename="/sf/data/applications/BD-SERVER/%s.log" % self.root
+        handler = RotatingFileHandler(filename=self.logfilename,
+                                      mode='a',
+                                      maxBytes=5 * 1024 * 1024,
+                                      backupCount=1,
+                                      delay=0)
+        if self.debug:
+            logging.basicConfig(level=logging.INFO,
+                                format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
+                                datefmt='%m-%d %H:%M:%S')
+        else:
+            logging.basicConfig(level=logging.INFO,
+                                format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
+                                datefmt='%m-%d %H:%M:%S',
+                                handlers=[handler,])
+        self.logger=logging.getLogger(self.program)
+
+        # setting up ZMQ interface
+        self.ZMQServerInfo(self.root,self.host,self.pid)       
+
+        # individual channels of main thread
+        self.PVstop = PV('%s:STOP%s' % (self.root,self.suffix))
+        self.PVstop.value = 0
+        self.PVstop.add_callback(self.stop)
+        self.PVping = PV('%s:PING%s' % (self.root,self.suffix))
+        self.PVlog =  PV('%s:LOG%s' % (self.root,self.suffix))
+
+    def stop(self,pvname=None,value=None,**kws):
+        self.logger.info('PV:STOP triggered at %s' % datetime.now().strftime('%Y-%m-%d %H:%M:%S'))
+        if value > 0:
+            self.running=False
+
+    def start(self):
+        self.logger.info('Starting Server: %s at %s' % (self.root,datetime.now().strftime('%Y-%m-%d %H:%M:%S')))
+        self.logger.info('PV Root: %s' % self.root
+        self.logger.info('Version: %s' % self.version)
+        self.logger.info('Host: %s' % self.host)
+        self.logger.info('PID: %d' % self.pid)
+        if self.debug:
+            self.logger.info('Debug Mode')
+ 
+    def run(self):
+        self.start()
+        self.running=True
+        while self.running:
+            time.sleep(1)
+            if self.ZMQPoll():
+                self.logger.info('Watchdog Server requested termination')
+                self.running = False
+            self.PVping.value = datetime.now().strftime('Last active at %Y-%m-%d %H:%M:%S')
+        self.terminate(None,None)
+
+    def terminate(self,signum,frame):
+        # stopping any sub thread with the server specific function terminateSubThreads
+        self.terminateSubThreads()
+        self.logger.info('Terminating Server at %s' % datetime.now().strftime('%Y-%m-%d %H:%M:%S'))
+        self.ZMQPoll('quit')  # informing the watchdog
+        print('Bunch Compressor Server is quitting...')
+        sys.exit(0)
+
+
+
+
+

util/zmqbase.py

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+import zmq
+import socket
+import sys
+
+class ZMQBase:
+    def __init__(self, host='127.0.0.1',port = 5678):
+
+        self.host=host
+        self.port = port
+        self.msg={'action':'','PV':'','host':'','pid':0}
+
+        self.REQUEST_TIMEOUT = 500
+        self.REQUEST_RETRIES = 2
+        self.SERVER_ENDPOINT = "tcp://%s:%d" % (host,port)
+        self.serverIsOffline=False    # assume that it is online
+
+    def ZMQServerInfo(self,PVroot,host,pid):
+        self.msg['PV']=PVroot
+        self.msg['host']=host
+        self.msg['pid']=pid
+
+
+    def ZMQPoll(self,tag='ping'):
+        self.msg['action']=tag
+        context = zmq.Context()
+        client = context.socket(zmq.REQ)
+        client.connect(self.SERVER_ENDPOINT)
+        client.send_pyobj(self.msg)
+
+        retries_left = self.REQUEST_RETRIES
+        while True:
+            if (client.poll(self.REQUEST_TIMEOUT) & zmq.POLLIN) != 0:
+                reply = client.recv_pyobj()
+                check = self.ZMQIdentifyReply(reply)
+                if self.serverIsOffline:
+                    self.logger.info("Watchdog server came online")
+                self.serverIsOffline=False
+                if check:
+                    return (reply['action'] == 'quit')
+                else:
+                    self.logger.warning("Malformed reply from server")
+                    continue
+
+            retries_left -= 1
+            # Socket is confused. Close and remove it.
+            client.setsockopt(zmq.LINGER, 0)
+            client.close()
+            if retries_left == 0:
+                if not self.serverIsOffline:
+                    self.logger.info("Watchdog server seems to be offline")
+                    self.serverIsOffline=True
+                return False
+
+            # Create new connection
+            client = context.socket(zmq.REQ)
+            client.connect(self.SERVER_ENDPOINT)
+            client.send_pyobj(self.msg)
+
+
+    def ZMQIdentifyReply(self,reply):
+        for field in ['PV','host','pid']:
+            if not reply[field] == self.msg[field]:
+                return False
+        return True
+            
+