Added tut 15

Author: chewett

README.md

@@ -14,19 +14,17 @@ Later we will get onto more complicated topics such as reaching a consensus of w
 
 Questions comments and suggestions can be raised the specific blog post or by using issues here.
 
-## Tutorial 14 - A simple webserver
+## Tutorial 15 - A more complex webserver
 
-This tutorial focuses on creating a simple webserver that displays
-the status of the master using the python library Bottle.
-This will form the basis of having a simple web interface to view
-the progress of the cluster and control it.
+This tutorial adds to the previous one by improving the display of the webserver
+by including information about the slaves attached. In addition to this the
+slaves are modified to use a UUID rather than a random integer to define them.
 
-The next tutorial will focus on improving the webserver to display
-slave information in addition to the current information.
+The next tutorial will focus on cleaning up the codebase in preparation for new features.
 
 The full details for
-[Tutorial 14 - A simple webserver](
-https://chewett.co.uk/blog/2127/raspberry-pi-cluster-node-14-a-simple-webserver/
+[Tutorial 15 - A more complex webserver](
+https://chewett.co.uk/blog/2179/raspberry-pi-cluster-node-15-a-more-complex-webserver/
 )
 
 ## Requirements

RpiCluster/RpiBasicSlaveThread.py

@@ -13,7 +13,7 @@ class RpiBasicSlaveThread(threading.Thread):
 
     def __init__(self, master_ip, socket_port):
         threading.Thread.__init__(self)
-        self.client_number = random.randint(1, 100000)
+        self.uuid = None
         self.server_address = (master_ip, socket_port)
         self.sock = None
 
@@ -36,6 +36,11 @@ def run(self):
 
             try:
                 logger.info("Sending an initial hello to master")
+                send_message(self.sock, create_payload("uuid", "info"))
+                message = get_message(self.sock)
+                self.uuid = message['payload']
+                logger.info("My assigned UUID is " + self.uuid)
+
                 send_message(self.sock, create_payload(get_base_machine_info(), 'computer_details'))
                 send_message(self.sock, create_payload("computer_details", "info"))
 
@@ -51,7 +56,7 @@ def run(self):
 
     def perform_action(self):
         logger.info("Now sending a keepalive to the master")
-        send_message(self.sock, create_payload("I am still alive, client: {num}".format(num=self.client_number)))
+        send_message(self.sock, create_payload("I am still alive, client: {num}".format(num=self.uuid)))
         time.sleep(5)
 
 

RpiCluster/RpiClusterClient.py

@@ -1,6 +1,7 @@
 import json
 import threading
 import time
+import uuid
 from DataPackager import get_message, create_payload, send_message
 from RpiClusterExceptions import DisconnectionException
 from MachineInfo import get_base_machine_info
@@ -9,10 +10,13 @@
 
 class RpiClusterClient(threading.Thread):
 
-    def __init__(self, clientsocket, address):
+    def __init__(self, master, clientsocket, address):
         threading.Thread.__init__(self)
+        self.uuid = uuid.uuid4().hex
+        self.master = master
         self.clientsocket = clientsocket
         self.address = address
+        self.node_specifications = None
 
     def run(self):
         try:
@@ -22,13 +26,20 @@ def run(self):
                 if message['type'] == 'message':
                     logger.info("Received message: " + message['payload'])
                 elif message['type'] == 'computer_details':
-                    logger.info("Computer specifications: " + json.dumps(message['payload']))
+                    self.node_specifications = message['payload']
+                    logger.info("Received Computer specifications: " + json.dumps(self.node_specifications))
                 elif message['type'] == 'info':
                     logger.info("Slave wants to know my info about " + message['payload'])
                     if message['payload'] == 'computer_details':
                         send_message(self.clientsocket, create_payload(get_base_machine_info(), "master_info"))
+                    elif message['payload'] == 'uuid':
+                        send_message(self.clientsocket, create_payload(self.uuid, "uuid"))
+                    elif message['payload'] == 'slave_details':
+                        slave_details = self.master.get_slave_details()
+                        send_message(self.clientsocket, create_payload(slave_details, "slave_details"))
                     else:
                         send_message(self.clientsocket, create_payload("unknown", "bad_message"))
         except DisconnectionException as e:
             logger.info("Got disconnection exception with message: " + e.message)
             logger.info("Shutting down slave connection handler")
+            self.master.remove_client(self)

RpiCluster/RpiMaster.py

@@ -0,0 +1,44 @@
+import time
+import datetime
+import socket
+from MainLogger import logger
+
+from RpiClusterClient import RpiClusterClient
+
+
+class RpiMaster:
+
+    def __init__(self, socket_bind_ip, socket_port):
+        self.socket_bind_ip = socket_bind_ip
+        self.socket_port = socket_port
+        self.connected_clients = {}
+
+    def start(self):
+        logger.info("Starting script...")
+
+        listening_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        listening_socket.bind((self.socket_bind_ip, self.socket_port))
+
+        listening_socket.listen(10)  # listen to 10 connects
+        while True:
+            (clientsocket, address) = listening_socket.accept()
+            logger.info("Got client at {address}".format(address=address))
+
+            rpi_client = RpiClusterClient(self, clientsocket, address)
+            self.connected_clients[rpi_client.uuid] = rpi_client
+            rpi_client.start()
+
+    def remove_client(self, rpi_client):
+        del self.connected_clients[rpi_client.uuid]
+
+    def get_slave_details(self):
+        slave_details = {}
+        for uuid in self.connected_clients:
+            slave_details[uuid] = {
+                "uuid": uuid,
+                "address": str(self.connected_clients[uuid].address[0]) + ":" + str(self.connected_clients[uuid].address[1]),
+
+            }
+
+        return slave_details
+

RpiCluster/RpiWebserverSlaveThread.py

@@ -2,20 +2,27 @@
 import datetime
 from MainLogger import logger
 from DataPackager import create_payload, get_message, send_message
+from MachineInfo import get_base_machine_info
+from RpiClusterExceptions import DisconnectionException
 from RpiBasicSlaveThread import RpiBasicSlaveThread
 
 
 class RpiWebserverSlaveThread(RpiBasicSlaveThread):
 
-    current_webserver_data = None
+    current_master_details = None
+    current_slave_details = None
     webserver_data_updated = None
 
     def perform_action(self):
         logger.info("Now sending a keepalive to the master")
-        send_message(self.sock, create_payload("I am still alive, client: {num}".format(num=self.client_number)))
+        send_message(self.sock, create_payload("I am still alive, client: {num}".format(num=self.uuid)))
         send_message(self.sock, create_payload("computer_details", "info"))
-        message = get_message(self.sock)
-        RpiWebserverSlaveThread.current_webserver_data = message['payload']
+        master_details = get_message(self.sock)
+        send_message(self.sock, create_payload("slave_details", "info"))
+        slave_details = get_message(self.sock)
+
+        RpiWebserverSlaveThread.current_master_details = master_details['payload']
+        RpiWebserverSlaveThread.current_slave_details = slave_details['payload']
         RpiWebserverSlaveThread.webserver_data_updated = datetime.datetime.now()
         time.sleep(5)
 

basic_master.py

@@ -4,7 +4,7 @@
 import socket
 import ConfigParser
 from RpiCluster.MainLogger import add_file_logger, logger
-from RpiCluster.RpiClusterClient import RpiClusterClient
+from RpiCluster.RpiMaster import RpiMaster
 
 config = ConfigParser.ConfigParser()
 config.read(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'rpicluster.cfg'))
@@ -13,18 +13,7 @@
 socket_bind_ip = config.get("master", "socket_bind_ip")
 
 add_file_logger("master.log")
-logger.info("Starting script...")
-
-socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-socket.bind((socket_bind_ip, socket_port))
-
-socket.listen(10) #listen to 10 connects
-while True:
-    (clientsocket, address) = socket.accept()
-    logger.info("Got client at {address}".format(address=address))
-
-    rpiClient = RpiClusterClient(clientsocket, address)
-    rpiClient.start()
-
 
+master = RpiMaster(socket_bind_ip, socket_port)
+master.start()
 

basic_webserver_slave.py

@@ -24,6 +24,8 @@
 @route('/')
 def index():
     return template("templates/ClusterHomepage.html",
-                    info=json.dumps(RpiWebserverSlaveThread.current_webserver_data, indent=4, sort_keys=True))
+                    masterinfo=json.dumps(RpiWebserverSlaveThread.current_master_details, indent=4, sort_keys=True),
+                    slaveinfo=json.dumps(RpiWebserverSlaveThread.current_slave_details, indent=4, sort_keys=True)
+                    )
 
 run(host=webserver_host, port=webserver_port)

templates/ClusterHomepage.html

@@ -12,7 +12,10 @@ <h1>Raspberry Pi Cluster Homepage</h1>
 <p>This page shows the status of the Raspberry Pi Cluster</p>
 
 <h2>Master Information</h2>
-<pre>{{info}}</pre>
+<pre>{{masterinfo}}</pre>
+
+<h2>Slave Information</h2>
+<pre>{{slaveinfo}}</pre>
 
 </body>
 </html>