Create daemon for graceful shutdown for rider location script. #180

utils/rider_location_cache/daemon.py

@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+
+import sys, os, time, atexit
+from signal import SIGTERM 
+
+class Daemon:
+	"""
+	A generic daemon class.
+	
+	Usage: subclass the Daemon class and override the run() method
+	"""
+	def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
+		self.stdin = stdin
+		self.stdout = stdout
+		self.stderr = stderr
+		self.pidfile = pidfile
+	
+	def daemonize(self):
+		"""
+		do the UNIX double-fork magic, see Stevens' "Advanced 
+		Programming in the UNIX Environment" for details (ISBN 0201563177)
+		http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
+		"""
+		try: 
+			pid = os.fork() 
+			if pid > 0:
+				# exit first parent
+				sys.exit(0) 
+		except OSError, e: 
+			sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
+			sys.exit(1)
+	
+		# decouple from parent environment
+		os.chdir("/") 
+		os.setsid() 
+		os.umask(0) 
+	
+		# do second fork
+		try: 
+			pid = os.fork() 
+			if pid > 0:
+				# exit from second parent
+				sys.exit(0) 
+		except OSError, e: 
+			sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
+			sys.exit(1) 
+	
+		# redirect standard file descriptors
+		sys.stdout.flush()
+		sys.stderr.flush()
+		si = file(self.stdin, 'r')
+		so = file(self.stdout, 'a+')
+		se = file(self.stderr, 'a+', 0)
+		os.dup2(si.fileno(), sys.stdin.fileno())
+		os.dup2(so.fileno(), sys.stdout.fileno())
+		os.dup2(se.fileno(), sys.stderr.fileno())
+	
+		# write pidfile
+		atexit.register(self.delpid)
+		pid = str(os.getpid())
+		file(self.pidfile,'w+').write("%s\n" % pid)
+	
+	def delpid(self):
+		os.remove(self.pidfile)
+
+	def start(self):
+		"""
+		Start the daemon
+		"""
+		# Check for a pidfile to see if the daemon already runs
+		try:
+			pf = file(self.pidfile,'r')
+			pid = int(pf.read().strip())
+			pf.close()
+		except IOError:
+			pid = None
+	
+		if pid:
+			message = "pidfile %s already exist. Daemon already running?\n"
+			sys.stderr.write(message % self.pidfile)
+			sys.exit(1)
+		
+		# Start the daemon
+		self.daemonize()
+		self.run()
+
+	def stop(self):
+		"""
+		Stop the daemon
+		"""
+		# Get the pid from the pidfile
+		try:
+			pf = file(self.pidfile,'r')
+			pid = int(pf.read().strip())
+			pf.close()
+		except IOError:
+			pid = None
+	
+		if not pid:
+			message = "pidfile %s does not exist. Daemon not running?\n"
+			sys.stderr.write(message % self.pidfile)
+			return # not an error in a restart
+
+		# Try killing the daemon process	
+		try:
+			while 1:
+				os.kill(pid, SIGTERM)
+				time.sleep(0.1)
+		except OSError, err:
+			err = str(err)
+			if err.find("No such process") > 0:
+				if os.path.exists(self.pidfile):
+					os.remove(self.pidfile)
+			else:
+				print str(err)
+				sys.exit(1)
+
+	def restart(self):
+		"""
+		Restart the daemon
+		"""
+		self.stop()
+		self.start()
+
+	def run(self):
+		"""
+		You should override this method when you subclass Daemon. It will be called after the process has been
+		daemonized by start() or restart().
+		"""

utils/rider_location_cache/rider_location_cache.py

@@ -1,6 +1,7 @@
 import paho.mqtt.client as mqtt
 import ssl
 from threading import Thread
+from daemon import Daemon
 import redis
 import time
 import signal
@@ -8,6 +9,34 @@ import sys
 import os
 import json
 
+class RiderLocationCache(object):
+
+    def run(self):
+        global client, redis_conn 
+        client = mqtt.Client()
+        client.on_connect = on_connect
+        # client.on_publish = on_publish
+        client.on_message = on_message
+
+        redis_conn = redis.StrictRedis(host='localhost', port=6379, db=0)
+
+        #client.tls_set(
+        #    "/etc/letsencrypt/live/resqaws.jankstudio.com/fullchain.pem", cert_reqs=ssl.CERT_NONE,
+        #    tls_version=ssl.PROTOCOL_TLSv1)
+        #client.tls_set(
+        #    "/root/aws_ssl_keys/fullchain.pem", cert_reqs=ssl.CERT_NONE,
+        #    tls_version=ssl.PROTOCOL_TLSv1)
+        #client.connect("resqaws.jankstudio.com", 8883, 60)
+        client.connect("localhost", 1883, 60)
+
+        #t = Thread(target=getRedis, args=(1,))
+
+        #t.start()
+
+        #signal.signal(signal.SIGINT, sigint_handler)
+        client.loop_forever()
+
+
 def init_subscriptions(client):
     print "subscribing to wildcard"
     client.subscribe('#')
@@ -60,29 +89,3 @@ def sigint_handler(signal, frame):
     print 'Interrupted'
     sys.exit(0)
 
-
-
-client = mqtt.Client()
-client.on_connect = on_connect
-# client.on_publish = on_publish
-client.on_message = on_message
-
-redis_conn = redis.StrictRedis(host='localhost', port=6379, db=0)
-
-
-#client.tls_set(
-#    "/etc/letsencrypt/live/resqaws.jankstudio.com/fullchain.pem", cert_reqs=ssl.CERT_NONE,
-#    tls_version=ssl.PROTOCOL_TLSv1)
-#client.tls_set(
-#    "/root/aws_ssl_keys/fullchain.pem", cert_reqs=ssl.CERT_NONE,
-#    tls_version=ssl.PROTOCOL_TLSv1)
-#client.connect("resqaws.jankstudio.com", 8883, 60)
-client.connect("localhost", 1883, 60)
-
-
-#t = Thread(target=getRedis, args=(1,))
-
-#t.start()
-
-#signal.signal(signal.SIGINT, sigint_handler)
-client.loop_forever()

utils/rider_location_cache/rider_location_daemon.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+
+import sys
+import time
+from daemon import Daemon
+import rider_location_cache
+
+class RiderLocationDaemon(Daemon):
+    def run(self):
+        print "mogol in daemon"
+        rider_location = rider_location_cache.RiderLocationCache()
+        rider_location.run()
+
+if __name__ == "__main__":
+    daemon = RiderLocationDaemon('/tmp/rider_location_daemon.pid')
+    if len(sys.argv) == 2:
+        if 'start' == sys.argv[1]:
+            daemon.start()
+        elif 'stop' == sys.argv[1]:
+            daemon.stop()
+        elif 'restart' == sys.argv[1]:
+            daemon.restart()
+        elif 'foreground' == sys.argv[1]:
+            daemon.run()
+        else:
+            print "Unknown command"
+            sys.exit(2)
+        sys.exit(0)
+    else:
+        print "usage: %s start|stop|restart" % sys.argv[0]
+        sys.exit(2)