1# -*- coding: utf-8 -*-
2#
3# This file is part of Glances.
4#
5# Copyright (C) 2019 Nicolargo <nicolas@nicolargo.com>
6#
7# Glances is free software; you can redistribute it and/or modify
8# it under the terms of the GNU Lesser General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11#
12# Glances is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15# GNU Lesser General Public License for more details.
16#
17# You should have received a copy of the GNU Lesser General Public License
18# along with this program. If not, see <http://www.gnu.org/licenses/>.
19
20"""Manage autodiscover Glances server (thk to the ZeroConf protocol)."""
21
22import socket
23import sys
24
25from glances.globals import BSD
26from glances.logger import logger
27
28try:
29    from zeroconf import (
30        __version__ as __zeroconf_version,
31        ServiceBrowser,
32        ServiceInfo,
33        Zeroconf
34    )
35    zeroconf_tag = True
36except ImportError:
37    zeroconf_tag = False
38
39# Zeroconf 0.17 or higher is needed
40if zeroconf_tag:
41    zeroconf_min_version = (0, 17, 0)
42    zeroconf_version = tuple([int(num) for num in __zeroconf_version.split('.')])
43    logger.debug("Zeroconf version {} detected.".format(__zeroconf_version))
44    if zeroconf_version < zeroconf_min_version:
45        logger.critical("Please install zeroconf 0.17 or higher.")
46        sys.exit(1)
47
48# Global var
49# Recent versions of the zeroconf python package doesnt like a zeroconf type that ends with '._tcp.'.
50# Correct issue: zeroconf problem with zeroconf_type = "_%s._tcp." % 'glances' #888
51zeroconf_type = "_%s._tcp.local." % 'glances'
52
53
54class AutoDiscovered(object):
55
56    """Class to manage the auto discovered servers dict."""
57
58    def __init__(self):
59        # server_dict is a list of dict (JSON compliant)
60        # [ {'key': 'zeroconf name', ip': '172.1.2.3', 'port': 61209, 'cpu': 3, 'mem': 34 ...} ... ]
61        self._server_list = []
62
63    def get_servers_list(self):
64        """Return the current server list (list of dict)."""
65        return self._server_list
66
67    def set_server(self, server_pos, key, value):
68        """Set the key to the value for the server_pos (position in the list)."""
69        self._server_list[server_pos][key] = value
70
71    def add_server(self, name, ip, port):
72        """Add a new server to the list."""
73        new_server = {
74            'key': name,  # Zeroconf name with both hostname and port
75            'name': name.split(':')[0],  # Short name
76            'ip': ip,  # IP address seen by the client
77            'port': port,  # TCP port
78            'username': 'glances',  # Default username
79            'password': '',  # Default password
80            'status': 'UNKNOWN',  # Server status: 'UNKNOWN', 'OFFLINE', 'ONLINE', 'PROTECTED'
81            'type': 'DYNAMIC'}  # Server type: 'STATIC' or 'DYNAMIC'
82        self._server_list.append(new_server)
83        logger.debug("Updated servers list (%s servers): %s" %
84                     (len(self._server_list), self._server_list))
85
86    def remove_server(self, name):
87        """Remove a server from the dict."""
88        for i in self._server_list:
89            if i['key'] == name:
90                try:
91                    self._server_list.remove(i)
92                    logger.debug("Remove server %s from the list" % name)
93                    logger.debug("Updated servers list (%s servers): %s" % (
94                        len(self._server_list), self._server_list))
95                except ValueError:
96                    logger.error(
97                        "Cannot remove server %s from the list" % name)
98
99
100class GlancesAutoDiscoverListener(object):
101
102    """Zeroconf listener for Glances server."""
103
104    def __init__(self):
105        # Create an instance of the servers list
106        self.servers = AutoDiscovered()
107
108    def get_servers_list(self):
109        """Return the current server list (list of dict)."""
110        return self.servers.get_servers_list()
111
112    def set_server(self, server_pos, key, value):
113        """Set the key to the value for the server_pos (position in the list)."""
114        self.servers.set_server(server_pos, key, value)
115
116    def add_service(self, zeroconf, srv_type, srv_name):
117        """Method called when a new Zeroconf client is detected.
118
119        Return True if the zeroconf client is a Glances server
120        Note: the return code will never be used
121        """
122        if srv_type != zeroconf_type:
123            return False
124        logger.debug("Check new Zeroconf server: %s / %s" %
125                     (srv_type, srv_name))
126        info = zeroconf.get_service_info(srv_type, srv_name)
127        if info:
128            new_server_ip = socket.inet_ntoa(info.address)
129            new_server_port = info.port
130
131            # Add server to the global dict
132            self.servers.add_server(srv_name, new_server_ip, new_server_port)
133            logger.info("New Glances server detected (%s from %s:%s)" %
134                        (srv_name, new_server_ip, new_server_port))
135        else:
136            logger.warning(
137                "New Glances server detected, but Zeroconf info failed to be grabbed")
138        return True
139
140    def remove_service(self, zeroconf, srv_type, srv_name):
141        """Remove the server from the list."""
142        self.servers.remove_server(srv_name)
143        logger.info(
144            "Glances server %s removed from the autodetect list" % srv_name)
145
146
147class GlancesAutoDiscoverServer(object):
148
149    """Implementation of the Zeroconf protocol (server side for the Glances client)."""
150
151    def __init__(self, args=None):
152        if zeroconf_tag:
153            logger.info("Init autodiscover mode (Zeroconf protocol)")
154            try:
155                self.zeroconf = Zeroconf()
156            except socket.error as e:
157                logger.error("Cannot start Zeroconf (%s)" % e)
158                self.zeroconf_enable_tag = False
159            else:
160                self.listener = GlancesAutoDiscoverListener()
161                self.browser = ServiceBrowser(
162                    self.zeroconf, zeroconf_type, self.listener)
163                self.zeroconf_enable_tag = True
164        else:
165            logger.error("Cannot start autodiscover mode (Zeroconf lib is not installed)")
166            self.zeroconf_enable_tag = False
167
168    def get_servers_list(self):
169        """Return the current server list (dict of dict)."""
170        if zeroconf_tag and self.zeroconf_enable_tag:
171            return self.listener.get_servers_list()
172        else:
173            return []
174
175    def set_server(self, server_pos, key, value):
176        """Set the key to the value for the server_pos (position in the list)."""
177        if zeroconf_tag and self.zeroconf_enable_tag:
178            self.listener.set_server(server_pos, key, value)
179
180    def close(self):
181        if zeroconf_tag and self.zeroconf_enable_tag:
182            self.zeroconf.close()
183
184
185class GlancesAutoDiscoverClient(object):
186
187    """Implementation of the zeroconf protocol (client side for the Glances server)."""
188
189    def __init__(self, hostname, args=None):
190        if zeroconf_tag:
191            zeroconf_bind_address = args.bind_address
192            try:
193                self.zeroconf = Zeroconf()
194            except socket.error as e:
195                logger.error("Cannot start zeroconf: {}".format(e))
196
197            # XXX *BSDs: Segmentation fault (core dumped)
198            # -- https://bitbucket.org/al45tair/netifaces/issues/15
199            if not BSD:
200                try:
201                    # -B @ overwrite the dynamic IPv4 choice
202                    if zeroconf_bind_address == '0.0.0.0':
203                        zeroconf_bind_address = self.find_active_ip_address()
204                except KeyError:
205                    # Issue #528 (no network interface available)
206                    pass
207
208            # Check IP v4/v6
209            address_family = socket.getaddrinfo(zeroconf_bind_address, args.port)[0][0]
210
211            # Start the zeroconf service
212            self.info = ServiceInfo(
213                zeroconf_type, '{}:{}.{}'.format(hostname, args.port, zeroconf_type),
214                address=socket.inet_pton(address_family, zeroconf_bind_address),
215                port=args.port, weight=0, priority=0, properties={}, server=hostname)
216            try:
217                self.zeroconf.register_service(self.info)
218            except socket.error as e:
219                logger.error("Error while announcing Glances server: {}".format(e))
220            else:
221                print("Announce the Glances server on the LAN (using {} IP address)".format(zeroconf_bind_address))
222        else:
223            logger.error("Cannot announce Glances server on the network: zeroconf library not found.")
224
225    @staticmethod
226    def find_active_ip_address():
227        """Try to find the active IP addresses."""
228        import netifaces
229        # Interface of the default gateway
230        gateway_itf = netifaces.gateways()['default'][netifaces.AF_INET][1]
231        # IP address for the interface
232        return netifaces.ifaddresses(gateway_itf)[netifaces.AF_INET][0]['addr']
233
234    def close(self):
235        if zeroconf_tag:
236            self.zeroconf.unregister_service(self.info)
237            self.zeroconf.close()
238