Update Python examples in Chapter 2

examples/Python/mtrelay.py

@@ -9,7 +9,8 @@
 import threading
 import zmq
 
-def step1(context=None):
+
+def step1(context: zmq.Context = None):
     """Step 1"""
     context = context or zmq.Context.instance()
     # Signal downstream to step 2
@@ -19,7 +20,7 @@ def step1(context=None):
     sender.send(b"")
 
 
-def step2(context=None):
+def step2(context: zmq.Context = None):
     """Step 2"""
     context = context or zmq.Context.instance()
     # Bind to inproc: endpoint, then start upstream thread

examples/Python/mtserver.py

@@ -10,24 +10,23 @@
 import zmq
 
 
-def worker_routine(worker_url, context=None):
+def worker_routine(worker_url: str,
+                   context: zmq.Context = None):
     """Worker routine"""
     context = context or zmq.Context.instance()
+
     # Socket to talk to dispatcher
     socket = context.socket(zmq.REP)
-
     socket.connect(worker_url)
 
     while True:
+        string = socket.recv()
+        print(f"Received request: [ {string} ]")
 
-        string  = socket.recv()
-
-        print("Received request: [ %s ]" % (string))
-
-        # do some 'work'
+        # Do some 'work'
         time.sleep(1)
 
-        #send reply back to client
+        # Send reply back to client
         socket.send(b"World")
 
 

examples/Python/psenvpub.py

@@ -8,11 +8,12 @@
 import time
 import zmq
 
+
 def main():
     """main method"""
 
     # Prepare our context and publisher
-    context   = zmq.Context()
+    context = zmq.Context()
     publisher = context.socket(zmq.PUB)
     publisher.bind("tcp://*:5563")
 

examples/Python/psenvsub.py

@@ -7,19 +7,20 @@
 """
 import zmq
 
+
 def main():
     """ main method """
 
     # Prepare our context and publisher
-    context    = zmq.Context()
+    context = zmq.Context()
     subscriber = context.socket(zmq.SUB)
     subscriber.connect("tcp://localhost:5563")
     subscriber.setsockopt(zmq.SUBSCRIBE, b"B")
 
     while True:
         # Read envelope with address
         [address, contents] = subscriber.recv_multipart()
-        print("[%s] %s" % (address, contents))
+        print(f"[{address}] {contents}")
 
     # We never get here but clean up anyhow
     subscriber.close()

examples/Python/rrclient.py

@@ -11,7 +11,7 @@
 socket.connect("tcp://localhost:5559")
 
 #  Do 10 requests, waiting each time for a response
-for request in range(1,11):
+for request in range(1, 11):
     socket.send(b"Hello")
     message = socket.recv()
-    print("Received reply %s [%s]" % (request, message))
+    print(f"Received reply {request} [{message}]")

examples/Python/rrworker.py

@@ -11,5 +11,5 @@
 
 while True:
     message = socket.recv()
-    print("Received request: %s" % message)
+    print(f"Received request: {message}")
     socket.send(b"World")

examples/Python/syncpub.py

@@ -6,18 +6,19 @@
 #  We wait for 10 subscribers
 SUBSCRIBERS_EXPECTED = 10
 
+
 def main():
     context = zmq.Context()
 
     # Socket to talk to clients
     publisher = context.socket(zmq.PUB)
     # set SNDHWM, so we don't drop messages for slow subscribers
     publisher.sndhwm = 1100000
-    publisher.bind('tcp://*:5561')
+    publisher.bind("tcp://*:5561")
 
     # Socket to receive signals
     syncservice = context.socket(zmq.REP)
-    syncservice.bind('tcp://*:5562')
+    syncservice.bind("tcp://*:5562")
 
     # Get synchronization from subscribers
     subscribers = 0
@@ -27,13 +28,14 @@ def main():
         # send synchronization reply
         syncservice.send(b'')
         subscribers += 1
-        print("+1 subscriber (%i/%i)" % (subscribers, SUBSCRIBERS_EXPECTED))
+        print(f"+1 subscriber ({subscribers}/{SUBSCRIBERS_EXPECTED})")
 
     # Now broadcast exactly 1M updates followed by END
     for i in range(1000000):
-        publisher.send(b'Rhubarb')
+        publisher.send(b"Rhubarb")
+
+    publisher.send(b"END")
 
-    publisher.send(b'END')
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()

examples/Python/syncsub.py

@@ -2,22 +2,22 @@
 #  Synchronized subscriber
 #
 import time
-
 import zmq
 
+
 def main():
     context = zmq.Context()
 
     # First, connect our subscriber socket
     subscriber = context.socket(zmq.SUB)
-    subscriber.connect('tcp://localhost:5561')
+    subscriber.connect("tcp://localhost:5561")
     subscriber.setsockopt(zmq.SUBSCRIBE, b'')
 
     time.sleep(1)
 
     # Second, synchronize with publisher
     syncclient = context.socket(zmq.REQ)
-    syncclient.connect('tcp://localhost:5562')
+    syncclient.connect("tcp://localhost:5562")
 
     # send a synchronization request
     syncclient.send(b'')
@@ -29,11 +29,12 @@ def main():
     nbr = 0
     while True:
         msg = subscriber.recv()
-        if msg == b'END':
+        if msg == b"END":
             break
         nbr += 1
 
-    print ('Received %d updates' % nbr)
+    print(f"Received {nbr} updates")
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()