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comparison libervia/backend/bridge/bridge_constructor/constructors/dbus/dbus_frontend_template.py @ 4071:4b842c1fb686

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refactoring: renamed `sat` package to `libervia.backend`
author Goffi <goffi@goffi.org>
date Fri, 02 Jun 2023 11:49:51 +0200
parents sat/bridge/bridge_constructor/constructors/dbus/dbus_frontend_template.py@524856bd7b19
children 0d7bb4df2343
comparison
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4070:d10748475025 4071:4b842c1fb686
1 #!/usr/bin/env python3
2
3 # SàT communication bridge
4 # Copyright (C) 2009-2021 Jérôme Poisson (goffi@goffi.org)
5
6 # This program is free software: you can redistribute it and/or modify
7 # it under the terms of the GNU Affero General Public License as published by
8 # the Free Software Foundation, either version 3 of the License, or
9 # (at your option) any later version.
10
11 # This program is distributed in the hope that it will be useful,
12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 # GNU Affero General Public License for more details.
15
16 # You should have received a copy of the GNU Affero General Public License
17 # along with this program. If not, see <http://www.gnu.org/licenses/>.
18
19 import asyncio
20 import dbus
21 import ast
22 from libervia.backend.core.i18n import _
23 from libervia.backend.tools import config
24 from libervia.backend.core.log import getLogger
25 from libervia.backend.core.exceptions import BridgeExceptionNoService, BridgeInitError
26 from dbus.mainloop.glib import DBusGMainLoop
27 from .bridge_frontend import BridgeException
28
29
30 DBusGMainLoop(set_as_default=True)
31 log = getLogger(__name__)
32
33
34 # Interface prefix
35 const_INT_PREFIX = config.config_get(
36 config.parse_main_conf(),
37 "",
38 "bridge_dbus_int_prefix",
39 "org.libervia.Libervia")
40 const_ERROR_PREFIX = const_INT_PREFIX + ".error"
41 const_OBJ_PATH = '/org/libervia/Libervia/bridge'
42 const_CORE_SUFFIX = ".core"
43 const_PLUGIN_SUFFIX = ".plugin"
44 const_TIMEOUT = 120
45
46
47 def dbus_to_bridge_exception(dbus_e):
48 """Convert a DBusException to a BridgeException.
49
50 @param dbus_e (DBusException)
51 @return: BridgeException
52 """
53 full_name = dbus_e.get_dbus_name()
54 if full_name.startswith(const_ERROR_PREFIX):
55 name = dbus_e.get_dbus_name()[len(const_ERROR_PREFIX) + 1:]
56 else:
57 name = full_name
58 # XXX: dbus_e.args doesn't contain the original DBusException args, but we
59 # receive its serialized form in dbus_e.args[0]. From that we can rebuild
60 # the original arguments list thanks to ast.literal_eval (secure eval).
61 message = dbus_e.get_dbus_message() # similar to dbus_e.args[0]
62 try:
63 message, condition = ast.literal_eval(message)
64 except (SyntaxError, ValueError, TypeError):
65 condition = ''
66 return BridgeException(name, message, condition)
67
68
69 class bridge:
70
71 def bridge_connect(self, callback, errback):
72 try:
73 self.sessions_bus = dbus.SessionBus()
74 self.db_object = self.sessions_bus.get_object(const_INT_PREFIX,
75 const_OBJ_PATH)
76 self.db_core_iface = dbus.Interface(self.db_object,
77 dbus_interface=const_INT_PREFIX + const_CORE_SUFFIX)
78 self.db_plugin_iface = dbus.Interface(self.db_object,
79 dbus_interface=const_INT_PREFIX + const_PLUGIN_SUFFIX)
80 except dbus.exceptions.DBusException as e:
81 if e._dbus_error_name in ('org.freedesktop.DBus.Error.ServiceUnknown',
82 'org.freedesktop.DBus.Error.Spawn.ExecFailed'):
83 errback(BridgeExceptionNoService())
84 elif e._dbus_error_name == 'org.freedesktop.DBus.Error.NotSupported':
85 log.error(_("D-Bus is not launched, please see README to see instructions on how to launch it"))
86 errback(BridgeInitError)
87 else:
88 errback(e)
89 else:
90 callback()
91 #props = self.db_core_iface.getProperties()
92
93 def register_signal(self, functionName, handler, iface="core"):
94 if iface == "core":
95 self.db_core_iface.connect_to_signal(functionName, handler)
96 elif iface == "plugin":
97 self.db_plugin_iface.connect_to_signal(functionName, handler)
98 else:
99 log.error(_('Unknown interface'))
100
101 def __getattribute__(self, name):
102 """ usual __getattribute__ if the method exists, else try to find a plugin method """
103 try:
104 return object.__getattribute__(self, name)
105 except AttributeError:
106 # The attribute is not found, we try the plugin proxy to find the requested method
107
108 def get_plugin_method(*args, **kwargs):
109 # We first check if we have an async call. We detect this in two ways:
110 # - if we have the 'callback' and 'errback' keyword arguments
111 # - or if the last two arguments are callable
112
113 async_ = False
114 args = list(args)
115
116 if kwargs:
117 if 'callback' in kwargs:
118 async_ = True
119 _callback = kwargs.pop('callback')
120 _errback = kwargs.pop('errback', lambda failure: log.error(str(failure)))
121 try:
122 args.append(kwargs.pop('profile'))
123 except KeyError:
124 try:
125 args.append(kwargs.pop('profile_key'))
126 except KeyError:
127 pass
128 # at this point, kwargs should be empty
129 if kwargs:
130 log.warning("unexpected keyword arguments, they will be ignored: {}".format(kwargs))
131 elif len(args) >= 2 and callable(args[-1]) and callable(args[-2]):
132 async_ = True
133 _errback = args.pop()
134 _callback = args.pop()
135
136 method = getattr(self.db_plugin_iface, name)
137
138 if async_:
139 kwargs['timeout'] = const_TIMEOUT
140 kwargs['reply_handler'] = _callback
141 kwargs['error_handler'] = lambda err: _errback(dbus_to_bridge_exception(err))
142
143 try:
144 return method(*args, **kwargs)
145 except ValueError as e:
146 if e.args[0].startswith("Unable to guess signature"):
147 # XXX: if frontend is started too soon after backend, the
148 # inspection misses methods (notably plugin dynamically added
149 # methods). The following hack works around that by redoing the
150 # cache of introspected methods signatures.
151 log.debug("using hack to work around inspection issue")
152 proxy = self.db_plugin_iface.proxy_object
153 IN_PROGRESS = proxy.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS
154 proxy._introspect_state = IN_PROGRESS
155 proxy._Introspect()
156 return self.db_plugin_iface.get_dbus_method(name)(*args, **kwargs)
157 raise e
158
159 return get_plugin_method
160
161 ##METHODS_PART##
162
163 class AIOBridge(bridge):
164
165 def register_signal(self, functionName, handler, iface="core"):
166 loop = asyncio.get_running_loop()
167 async_handler = lambda *args: asyncio.run_coroutine_threadsafe(handler(*args), loop)
168 return super().register_signal(functionName, async_handler, iface)
169
170 def __getattribute__(self, name):
171 """ usual __getattribute__ if the method exists, else try to find a plugin method """
172 try:
173 return object.__getattribute__(self, name)
174 except AttributeError:
175 # The attribute is not found, we try the plugin proxy to find the requested method
176 def get_plugin_method(*args, **kwargs):
177 loop = asyncio.get_running_loop()
178 fut = loop.create_future()
179 method = getattr(self.db_plugin_iface, name)
180 reply_handler = lambda ret=None: loop.call_soon_threadsafe(
181 fut.set_result, ret)
182 error_handler = lambda err: loop.call_soon_threadsafe(
183 fut.set_exception, dbus_to_bridge_exception(err))
184 try:
185 method(
186 *args,
187 **kwargs,
188 timeout=const_TIMEOUT,
189 reply_handler=reply_handler,
190 error_handler=error_handler
191 )
192 except ValueError as e:
193 if e.args[0].startswith("Unable to guess signature"):
194 # same hack as for bridge.__getattribute__
195 log.warning("using hack to work around inspection issue")
196 proxy = self.db_plugin_iface.proxy_object
197 IN_PROGRESS = proxy.INTROSPECT_STATE_INTROSPECT_IN_PROGRESS
198 proxy._introspect_state = IN_PROGRESS
199 proxy._Introspect()
200 self.db_plugin_iface.get_dbus_method(name)(
201 *args,
202 **kwargs,
203 timeout=const_TIMEOUT,
204 reply_handler=reply_handler,
205 error_handler=error_handler
206 )
207
208 else:
209 raise e
210 return fut
211
212 return get_plugin_method
213
214 def bridge_connect(self):
215 loop = asyncio.get_running_loop()
216 fut = loop.create_future()
217 super().bridge_connect(
218 callback=lambda: loop.call_soon_threadsafe(fut.set_result, None),
219 errback=lambda e: loop.call_soon_threadsafe(fut.set_exception, e)
220 )
221 return fut
222
223 ##ASYNC_METHODS_PART##