stratum.py

   1 import json
   2 import socket
   3 import threading
   4 import time
   5 import Queue as queue
   6
   7 class Processor(threading.Thread):
   8
   9     def __init__(self):
  10         self.shared = None
  11         self.lock = threading.Lock()
  12         self.sessions = []
  13         threading.Thread.__init__(self)
  14         self.daemon = True
  15
  16     def add_session(self, session):
  17         with self.lock:
  18             self.sessions.append(session)
  19
  20     def run(self):
  21         if self.shared is None:
  22             raise TypeError("self.shared not set in Processor")
  23         while not self.shared.stopped():
  24             # Deep copy entire sessions list and blank it
  25             # This is done to minimise lock contention
  26             with self.lock:
  27                 sessions = self.sessions[:]
  28                 self.sessions = []
  29             for session in sessions:
  30                 if not session.stopped():
  31                     # If session is still alive then re-add it back
  32                     # to our internal register
  33                     self.add_session(session)
  34                     self.process(session)
  35
  36     def process(self, session):
  37         request = session.pop_request()
  38         print "New request", request
  39         # Execute and when ready, you call
  40         # session.push_response(response)
  41
  42 class Session:
  43
  44     def __init__(self, connection, address):
  45         self._connection = connection
  46         self.address = address
  47         self._stopped = False
  48         self.lock = threading.Lock()
  49
  50         self.request_queue = queue.Queue()
  51         self.response_queue = queue.Queue()
  52
  53     def stop(self):
  54         self._connection.close()
  55         print "Terminating connection:", self.address[0]
  56         with self.lock:
  57             self._stopped = True
  58
  59     def stopped(self):
  60         with self.lock:
  61             return self._stopped
  62
  63     def connection(self):
  64         if self.stopped():
  65             raise Exception("Session was stopped")
  66         else:
  67             return self._connection
  68
  69     def push_request(self, item):
  70         self.request_queue.put(item)
  71
  72     def pop_request(self):
  73         return self.request_queue.get()
  74
  75     def push_response(self, item):
  76         self.response_queue.put(item)
  77
  78     def pop_response(self):
  79         return self.response_queue.get()
  80
  81 class TcpClientResponder(threading.Thread):
  82
  83     def __init__(self, shared, session):
  84         self.shared = shared
  85         self.session = session
  86         threading.Thread.__init__(self)
  87
  88     def run(self):
  89         while not self.shared.stopped() or self.session.stopped():
  90             response = self.session.pop_response()
  91             raw_response = json.dumps(response)
  92             # Possible race condition here by having session
  93             # close connection?
  94             # I assume Python connections are thread safe interfaces
  95             connection = self.session.connection()
  96             try:
  97                 connection.send(raw_response + "\n")
  98             except:
  99                 self.session.stop()
 100
 101 class TcpClientRequestor(threading.Thread):
 102
 103     def __init__(self, shared, session):
 104         self.shared = shared
 105         self.message = ""
 106         self.session = session
 107         threading.Thread.__init__(self)
 108
 109     def run(self):
 110         while not self.shared.stopped():
 111             if not self.update():
 112                 self.session.stop()
 113                 return
 114
 115     def update(self):
 116         data = self.receive()
 117         if data is None:
 118             # close_session
 119             self.stop()
 120             return False
 121
 122         self.message += data
 123         if not self.parse():
 124             return False
 125         return True
 126
 127     def receive(self):
 128         try:
 129             return self.session.connection().recv(1024)
 130         except socket.error:
 131             return None
 132
 133     def parse(self):
 134         raw_buffer = self.message.find('\n')
 135         if raw_buffer == -1:
 136             return True
 137
 138         raw_command = self.message[0:raw_buffer].strip()
 139         self.message = self.message[raw_buffer + 1:]
 140         if raw_command == 'quit':
 141             return False
 142
 143         try:
 144             command = json.loads(raw_command)
 145         except:
 146             self.session.push_response(
 147                 {"error": "bad JSON", "request": raw_command})
 148             return True
 149
 150         try:
 151             # Try to load vital fields, and return an error if
 152             # unsuccessful.
 153             message_id = command['id']
 154             method = command['method']
 155         except KeyError:
 156             # Return an error JSON in response.
 157             self.session.push_response(
 158                 {"error": "syntax error", "request": raw_command})
 159         else:
 160             self.session.push_request(command)
 161
 162         return True
 163
 164 class TcpServer(threading.Thread):
 165
 166     def __init__(self, shared, processor):
 167         self.shared = shared
 168         self.processor = processor
 169         self.clients = []
 170         threading.Thread.__init__(self)
 171         self.daemon = True
 172
 173     def run(self):
 174         print "TCP server started."
 175         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 176         sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
 177         sock.bind(("localhost", 50001))
 178         sock.listen(1)
 179         while not self.shared.stopped():
 180             session = Session(*sock.accept())
 181             client_req = TcpClientRequestor(self.shared, session)
 182             client_req.start()
 183             client_res = TcpClientResponder(self.shared, session)
 184             client_res.start()
 185             self.processor.add_session(session)
 186
 187 class Shared:
 188
 189     def __init__(self):
 190         self.lock = threading.Lock()
 191         self._stopped = False
 192
 193     def stop(self):
 194         print "Stopping Stratum"
 195         with self.lock:
 196             self._stopped = True
 197
 198     def stopped(self):
 199         with self.lock:
 200             return self._stopped
 201
 202 class Stratum:
 203
 204     def start(self, processor):
 205         shared = Shared()
 206         # Bind shared to processor since constructor is user defined
 207         processor.shared = shared
 208         processor.start()
 209         # Create various transports we need
 210         transports = TcpServer(shared, processor),
 211         for server in transports:
 212             server.start()
 213         while not shared.stopped():
 214             if raw_input() == "quit":
 215                 shared.stop()
 216             time.sleep(1)
 217
 218 if __name__ == "__main__":
 219     processor = Processor()
 220     app = Stratum()
 221     app.start(processor)
 222