#
# Create a number of "publishers" on the localhost, all
# using a different socket. Each publisher will publish
# periodic messages containing json formatted data that
# can be consumed by the client for display, mimicing
# data from many different computers.
#

import zmq
import json
import time
import threading
import random

Nservers = 10
starting_port = 5555

# Each server is represented by an object of this class
class HDserver:
	def __init__(self, port):
		self.port = port
		self.host = 'fake_host%02d' % port

		# Set up publisher
		self.context = zmq.Context()
		self.socket = self.context.socket(zmq.PUB)
		self.socket.bind("tcp://*:%d" % port)

		# Initialize with some random values
		self.datarate_mean   = random.uniform( 100.0, 500.0 ) # MB/s
		self.datarate_sigma  = random.uniform( 10.0, 50.0 ) # MB/s
		self.Nfiles = random.randint( 5, 100 )

		# Run server loop in separate thread
		self.thread = threading.Thread(target=self.Loop)
		self.done = False
		self.thread.start()

	# This is run in a separate thread publishing messages periodically
	# until told to stop via the End() proc being called
	def Loop(self):
		print('Starting thread for port %d' % self.port)
		time.sleep(random.randrange(10)) # sleep random amount of time to put servers out of sync

		# Loop continuously
		while not self.done:
			print('-- port %d:' % self.port)

			# Create dictionary of values to send
			myinfo = {}
			myinfo['host'] = self.host
			myinfo['avg5min'] = random.normalvariate( self.datarate_mean, self.datarate_sigma )
			myinfo['Nfiles']   = self.Nfiles = self.Nfiles + random.randrange(10)

			# Send entire dictionary as json file
			myjson = json.dumps( myinfo )
			self.socket.send_string(myjson)
			time.sleep(3)
	
	# Stop the server thread
	def End(self):
		print('Ending thread for port %d ...' % self.port)
		self.done = True
		threading.Thread(target=lambda a: a.thread.join(), args=(self)) # join in separate thread so we can return immediately
		print( 'Port %d done.' % self.port )

#-----------------------------------------------------------------------------------
# main

# Create N servers
servers =[]
for i in range(0,Nservers):
	port = starting_port + i
	server = HDserver(port)
	servers.append( server )

# Loop continuously. Put it in a try-except block so keyboard interrupts are caught cleanly
try:
	while True: time.sleep(1)
except:
	pass

print('\nShutting down servers ....')
for s in servers: s.End()
print('\nFinished.')