fix possible race condition in collect_gargage
[electrum-server.git] / processor.py
1 import json
2 import Queue as queue
3 import socket
4 import threading
5 import time
6 import traceback
7 import sys
8
9 from utils import random_string, timestr, print_log
10
11
12 class Shared:
13
14     def __init__(self, config):
15         self.lock = threading.Lock()
16         self._stopped = False
17         self.config = config
18
19     def stop(self):
20         print_log("Stopping Stratum")
21         with self.lock:
22             self._stopped = True
23
24     def stopped(self):
25         with self.lock:
26             return self._stopped
27
28
29 class Processor(threading.Thread):
30
31     def __init__(self):
32         threading.Thread.__init__(self)
33         self.daemon = True
34         self.dispatcher = None
35         self.queue = queue.Queue()
36
37     def process(self, request):
38         pass
39
40     def add_request(self, request):
41         self.queue.put(request)
42
43     def push_response(self, response):
44         #print "response", response
45         self.dispatcher.request_dispatcher.push_response(response)
46
47     def run(self):
48         while not self.shared.stopped():
49             request = self.queue.get(10000000000)
50             try:
51                 self.process(request)
52             except:
53                 traceback.print_exc(file=sys.stdout)
54
55         print_log("processor terminating")
56
57
58 class Dispatcher:
59
60     def __init__(self, config):
61         self.shared = Shared(config)
62         self.request_dispatcher = RequestDispatcher(self.shared)
63         self.request_dispatcher.start()
64         self.response_dispatcher = \
65             ResponseDispatcher(self.shared, self.request_dispatcher)
66         self.response_dispatcher.start()
67
68     def register(self, prefix, processor):
69         processor.dispatcher = self
70         processor.shared = self.shared
71         processor.start()
72         self.request_dispatcher.processors[prefix] = processor
73
74
75 class RequestDispatcher(threading.Thread):
76
77     def __init__(self, shared):
78         self.shared = shared
79         threading.Thread.__init__(self)
80         self.daemon = True
81         self.request_queue = queue.Queue()
82         self.response_queue = queue.Queue()
83         self.internal_ids = {}
84         self.internal_id = 1
85         self.lock = threading.Lock()
86         self.sessions = []
87         self.processors = {}
88
89     def push_response(self, item):
90         self.response_queue.put(item)
91
92     def pop_response(self):
93         return self.response_queue.get()
94
95     def push_request(self, session, item):
96         self.request_queue.put((session, item))
97
98     def pop_request(self):
99         return self.request_queue.get()
100
101     def get_session_by_address(self, address):
102         for x in self.sessions:
103             if x.address == address:
104                 return x
105
106     def get_session_id(self, internal_id):
107         with self.lock:
108             return self.internal_ids.pop(internal_id)
109
110     def store_session_id(self, session, msgid):
111         with self.lock:
112             self.internal_ids[self.internal_id] = session, msgid
113             r = self.internal_id
114             self.internal_id += 1
115             return r
116
117     def run(self):
118         if self.shared is None:
119             raise TypeError("self.shared not set in Processor")
120         while not self.shared.stopped():
121             session, request = self.pop_request()
122             try:
123                 self.do_dispatch(session, request)
124             except:
125                 traceback.print_exc(file=sys.stdout)
126
127         self.stop()
128
129     def stop(self):
130         pass
131
132     def do_dispatch(self, session, request):
133         """ dispatch request to the relevant processor """
134
135         method = request['method']
136         params = request.get('params', [])
137         suffix = method.split('.')[-1]
138
139         if session is not None:
140             is_new = session.protocol_version >= 0.5
141             if suffix == 'subscribe':
142                 session.subscribe_to_service(method, params)
143
144         # store session and id locally
145         request['id'] = self.store_session_id(session, request['id'])
146
147         prefix = request['method'].split('.')[0]
148         try:
149             p = self.processors[prefix]
150         except:
151             print_log("error: no processor for", prefix)
152             return
153
154         p.add_request(request)
155
156         if method in ['server.version']:
157             session.version = params[0]
158             try:
159                 session.protocol_version = float(params[1])
160             except:
161                 pass
162
163             #if session.protocol_version < 0.6:
164             #    print_log("stopping session from old client", session.protocol_version)
165             #    session.stop()
166
167     def get_sessions(self):
168         with self.lock:
169             r = self.sessions[:]
170         return r
171
172     def add_session(self, session):
173         with self.lock:
174             self.sessions.append(session)
175
176     def collect_garbage(self):
177         # Deep copy entire sessions list and blank it
178         # This is done to minimize lock contention
179         with self.lock:
180             sessions = self.sessions[:]
181
182         active_sessions = []
183         for session in sessions:
184             if not session.stopped():
185                 # If session is still alive then re-add it back
186                 # to our internal register
187                 active_sessions.append(session)
188
189         with self.lock:
190             self.sessions = active_sessions[:]
191
192
193
194 class Session:
195
196     def __init__(self):
197         self._stopped = False
198         self.lock = threading.Lock()
199         self.subscriptions = []
200         self.address = ''
201         self.name = ''
202         self.version = 'unknown'
203         self.protocol_version = 0.
204         self.time = time.time()
205         threading.Timer(2, self.info).start()
206
207     # Debugging method. Doesn't need to be threadsafe.
208     def info(self):
209         for sub in self.subscriptions:
210             #print sub
211             method = sub[0]
212             if method == 'blockchain.address.subscribe':
213                 addr = sub[1]
214                 break
215         else:
216             addr = None
217
218         if self.subscriptions:
219             print_log("%4s" % self.name,
220                       "%15s" % self.address,
221                       "%35s" % addr,
222                       "%3d" % len(self.subscriptions),
223                       self.version)
224
225     def stopped(self):
226         with self.lock:
227             return self._stopped
228
229     def subscribe_to_service(self, method, params):
230         subdesc = self.build_subdesc(method, params)
231         with self.lock:
232             if subdesc is not None:
233                 self.subscriptions.append(subdesc)
234
235     # subdesc = A subscription description
236     @staticmethod
237     def build_subdesc(method, params):
238         if method == "blockchain.numblocks.subscribe":
239             return method,
240         elif method == "blockchain.headers.subscribe":
241             return method,
242         elif method in ["blockchain.address.subscribe"]:
243             if not params:
244                 return None
245             else:
246                 return method, params[0]
247         else:
248             return None
249
250     def contains_subscription(self, subdesc):
251         with self.lock:
252             return subdesc in self.subscriptions
253
254
255 class ResponseDispatcher(threading.Thread):
256
257     def __init__(self, shared, request_dispatcher):
258         self.shared = shared
259         self.request_dispatcher = request_dispatcher
260         threading.Thread.__init__(self)
261         self.daemon = True
262
263     def run(self):
264         while not self.shared.stopped():
265             self.update()
266
267     def update(self):
268         response = self.request_dispatcher.pop_response()
269         #print "pop response", response
270         internal_id = response.get('id')
271         method = response.get('method')
272         params = response.get('params')
273
274         # A notification
275         if internal_id is None:  # and method is not None and params is not None:
276             found = self.notification(method, params, response)
277             if not found and method == 'blockchain.address.subscribe':
278                 request = {
279                     'id': None,
280                     'method': method.replace('.subscribe', '.unsubscribe'),
281                     'params': [self.shared.config.get('server', 'password')] + params,
282                 }
283
284                 self.request_dispatcher.push_request(None, request)
285         # A response
286         elif internal_id is not None:
287             self.send_response(internal_id, response)
288         else:
289             print_log("no method", response)
290
291     def notification(self, method, params, response):
292         subdesc = Session.build_subdesc(method, params)
293         found = False
294         for session in self.request_dispatcher.sessions:
295             if session.stopped():
296                 continue
297             if session.contains_subscription(subdesc):
298                 session.send_response(response)
299                 found = True
300         # if not found: print_log("no subscriber for", subdesc)
301         return found
302
303     def send_response(self, internal_id, response):
304         session, message_id = self.request_dispatcher.get_session_id(internal_id)
305         if session:
306             response['id'] = message_id
307             session.send_response(response)
308         #else:
309         #    print_log("send_response: no session", message_id, internal_id, response )