1"""The client and server for a basic ping-pong style heartbeat.
2"""
3
4#-----------------------------------------------------------------------------
5#  Copyright (C) 2008-2011  The IPython Development Team
6#
7#  Distributed under the terms of the BSD License.  The full license is in
8#  the file COPYING, distributed as part of this software.
9#-----------------------------------------------------------------------------
10
11#-----------------------------------------------------------------------------
12# Imports
13#-----------------------------------------------------------------------------
14
15import errno
16import os
17import socket
18from threading import Thread
19
20import zmq
21
22from jupyter_client.localinterfaces import localhost
23
24#-----------------------------------------------------------------------------
25# Code
26#-----------------------------------------------------------------------------
27
28
29class Heartbeat(Thread):
30    "A simple ping-pong style heartbeat that runs in a thread."
31
32    def __init__(self, context, addr=None):
33        if addr is None:
34            addr = ('tcp', localhost(), 0)
35        Thread.__init__(self)
36        self.context = context
37        self.transport, self.ip, self.port = addr
38        self.original_port = self.port
39        if self.original_port == 0:
40            self.pick_port()
41        self.addr = (self.ip, self.port)
42        self.daemon = True
43
44    def pick_port(self):
45        if self.transport == 'tcp':
46            s = socket.socket()
47            # '*' means all interfaces to 0MQ, which is '' to socket.socket
48            s.bind(('' if self.ip == '*' else self.ip, 0))
49            self.port = s.getsockname()[1]
50            s.close()
51        elif self.transport == 'ipc':
52            self.port = 1
53            while os.path.exists("%s-%s" % (self.ip, self.port)):
54                self.port = self.port + 1
55        else:
56            raise ValueError("Unrecognized zmq transport: %s" % self.transport)
57        return self.port
58
59    def _try_bind_socket(self):
60        c = ':' if self.transport == 'tcp' else '-'
61        return self.socket.bind('%s://%s' % (self.transport, self.ip) + c + str(self.port))
62
63    def _bind_socket(self):
64        try:
65            win_in_use = errno.WSAEADDRINUSE
66        except AttributeError:
67            win_in_use = None
68
69        # Try up to 100 times to bind a port when in conflict to avoid
70        # infinite attempts in bad setups
71        max_attempts = 1 if self.original_port else 100
72        for attempt in range(max_attempts):
73            try:
74                self._try_bind_socket()
75            except zmq.ZMQError as ze:
76                if attempt == max_attempts - 1:
77                    raise
78                # Raise if we have any error not related to socket binding
79                if ze.errno != errno.EADDRINUSE and ze.errno != win_in_use:
80                    raise
81                # Raise if we have any error not related to socket binding
82                if self.original_port == 0:
83                    self.pick_port()
84                else:
85                    raise
86            else:
87                return
88
89    def run(self):
90        self.socket = self.context.socket(zmq.ROUTER)
91        self.socket.linger = 1000
92        try:
93            self._bind_socket()
94        except Exception:
95            self.socket.close()
96            raise
97
98        while True:
99            try:
100                zmq.device(zmq.QUEUE, self.socket, self.socket)
101            except zmq.ZMQError as e:
102                if e.errno == errno.EINTR:
103                    # signal interrupt, resume heartbeat
104                    continue
105                elif e.errno == zmq.ETERM:
106                    # context terminated, close socket and exit
107                    try:
108                        self.socket.close()
109                    except zmq.ZMQError:
110                        # suppress further errors during cleanup
111                        # this shouldn't happen, though
112                        pass
113                    break
114                elif e.errno == zmq.ENOTSOCK:
115                    # socket closed elsewhere, exit
116                    break
117                else:
118                    raise
119            else:
120                break
121