1 # -----------------------------------------------------------------------
2 # Copyright (C) 2008 Equinox Software, Inc.
3 # Bill Erickson <erickson@esilibrary.com>
5 # This program is free software; you can redistribute it and/or
6 # modify it under the terms of the GNU General Public License
7 # as published by the Free Software Foundation; either version 2
8 # of the License, or (at your option) any later version.
10 # This program is distributed in the hope that it will be useful,
11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 # GNU General Public License for more details.
15 # You should have received a copy of the GNU General Public License
16 # along with this program; if not, write to the Free Software
17 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 # -----------------------------------------------------------------------
21 import os, sys, threading, fcntl, socket, errno, signal, time
22 import osrf.log, osrf.conf, osrf.net, osrf.system, osrf.stack, osrf.app, osrf.const
25 # used to define the size of the PID/size leader in
26 # status and data messages passed to and from children
29 class Controller(object):
31 OpenSRF forking request server.
34 def __init__(self, service):
35 self.service = service # service name
36 self.application = None # the application we're serving
37 self.max_requests = 0 # max child requests
38 self.max_children = 0 # max num of child processes
39 self.min_childen = 0 # min num of child processes
40 self.num_children = 0 # current num children
41 self.child_idx = 0 # current index into the children array
42 self.children = [] # list of children
43 self.osrf_handle = None # xmpp handle
44 self.routers = [] # list of registered routers
45 self.keepalive = 0 # how long to wait for subsequent, stateful requests
47 # Global status socketpair. All children relay their
48 # availability info to the parent through this socketpair.
49 self.read_status, self.write_status = socket.socketpair()
52 settings = osrf.set.get('activeapps.%s' % self.service)
56 ''' Closes management sockets, kills children, reaps children, exits '''
58 osrf.log.log_info("Shutting down...")
59 self.cleanup_routers()
61 self.read_status.shutdown(socket.SHUT_RDWR)
62 self.write_status.shutdown(socket.SHUT_RDWR)
63 self.read_status.close()
64 self.write_status.close()
66 for child in self.children:
67 child.read_data.shutdown(socket.SHUT_RDWR)
68 child.write_data.shutdown(socket.SHUT_RDWR)
69 child.read_data.close()
70 child.write_data.close()
72 os.kill(0, signal.SIGKILL)
73 self.reap_children(True)
77 def handle_signals(self):
78 ''' Installs SIGINT and SIGTERM handlers '''
79 def handler(signum, frame):
81 signal.signal(signal.SIGINT, handler)
82 signal.signal(signal.SIGTERM, handler)
87 osrf.net.get_network_handle().disconnect()
88 osrf.net.clear_network_handle()
92 time.sleep(.5) # give children a chance to connect before we start taking data
93 self.osrf_handle = osrf.system.System.net_connect(
94 resource = '%s_listener' % self.service,
95 service = self.service
98 # clear the recv callback so inbound messages do not filter through the opensrf stack
99 self.osrf_handle.receive_callback = None
101 # connect to our listening routers
102 self.register_routers()
105 osrf.log.log_debug("entering main server loop...")
106 while True: # main server loop
110 data = self.osrf_handle.recv(-1).to_xml()
112 if self.try_avail_child(data):
115 if self.try_new_child(data):
118 self.wait_for_child()
120 except KeyboardInterrupt:
122 #except Exception, e:
123 #osrf.log.log_error("server exiting with exception: %s" % e.message)
127 def try_avail_child(self, data):
128 ''' Trys to send current request data to an available child process '''
130 while ctr < self.num_children:
132 if self.child_idx >= self.num_children:
134 child = self.children[self.child_idx]
137 osrf.log.log_internal("sending data to available child")
138 self.write_child(child, data)
145 def try_new_child(self, data):
146 ''' Tries to spawn a new child to send request data to '''
147 if self.num_children < self.max_children:
148 osrf.log.log_internal("spawning new child to handle data")
149 child = self.spawn_child()
150 self.write_child(child, data)
154 def try_wait_child(self, data):
155 ''' Waits for a child to become available '''
156 osrf.log.log_warn("No children available, waiting...")
157 child = self.check_status(True)
158 self.write_child(child, data)
161 def write_child(self, child, data):
162 ''' Sends data to the child process '''
163 child.available = False
164 child.write_data.sendall(str(len(data)).rjust(SIZE_PAD) + data)
168 def check_status(self, block=False):
169 ''' Checks to see if any children have indicated they are done with
170 their current request. If block is true, this will wait
171 indefinitely for a child to be free. '''
176 pid = self.read_status.recv(SIZE_PAD)
179 self.read_status.setblocking(0)
180 pid = self.read_status.recv(SIZE_PAD)
181 except socket.error, e:
182 if e.args[0] != errno.EAGAIN:
184 self.read_status.setblocking(1)
188 child = [c for c in self.children if c.pid == pid][0]
189 child.available = True
194 def reap_children(self, done=False):
195 ''' Uses waitpid() to reap the children. If necessary, new children are spawned '''
202 (pid, status) = os.waitpid(0, options)
205 self.spawn_children()
207 osrf.log.log_debug("reaping child %d" % pid)
208 self.num_children -= 1
209 self.children = [c for c in self.children if c.pid != pid]
213 def spawn_children(self):
214 ''' Launches up to min_children child processes '''
215 while self.num_children < self.min_children:
218 def spawn_child(self):
219 ''' Spawns a new child process '''
222 child.read_data, child.write_data = socket.socketpair()
223 child.pid = os.fork()
226 self.num_children += 1
227 self.children.append(child)
228 osrf.log.log_debug("spawned child %d : %d total" % (child.pid, self.num_children))
231 child.pid = os.getpid()
234 osrf.net.get_network_handle().disconnect()
235 osrf.log.log_internal("child exiting...")
238 def register_routers(self):
239 ''' Registers this application instance with all configured routers '''
240 routers = osrf.conf.get('routers.router')
242 if not isinstance(routers, list):
245 for router in routers:
246 if isinstance(router, dict):
247 if not 'services' in router or \
248 self.service in router['services']['service']:
249 target = "%s@%s/router" % (router['name'], router['domain'])
250 self.register_router(target)
252 router_name = osrf.conf.get('router_name')
253 target = "%s@%s/router" % (router_name, router)
254 self.register_router(target)
257 def register_router(self, target):
258 ''' Registers with a single router '''
259 osrf.log.log_info("registering with router %s" % target)
260 self.routers.append(target)
262 reg_msg = osrf.net.NetworkMessage(
264 body = 'registering...',
265 router_command = 'register',
266 router_class = self.service
269 self.osrf_handle.send(reg_msg)
271 def cleanup_routers(self):
272 ''' Un-registers with all connected routers '''
273 for target in self.routers:
274 osrf.log.log_info("un-registering with router %s" % target)
275 unreg_msg = osrf.net.NetworkMessage(
277 body = 'un-registering...',
278 router_command = 'unregister',
279 router_class = self.service
281 self.osrf_handle.send(unreg_msg)
285 ''' Models a single child process '''
287 def __init__(self, controller):
288 self.controller = controller # our Controller object
289 self.num_requests = 0 # how many requests we've served so far
290 self.read_data = None # the child reads data from the controller on this socket
291 self.write_data = None # the controller sends data to the child on this socket
292 self.available = True # true if this child is not currently serving a request
293 self.pid = 0 # my process id
297 ''' Loops, processing data, until max_requests is reached '''
300 size = int(self.read_data.recv(SIZE_PAD) or 0)
301 data = self.read_data.recv(size)
302 osrf.log.log_internal("recv'd data " + data)
303 session = osrf.stack.push(osrf.net.NetworkMessage.from_xml(data))
304 self.keepalive_loop(session)
305 self.num_requests += 1
306 if self.num_requests == self.controller.max_requests:
309 except KeyboardInterrupt:
311 # run the exit handler
312 osrf.app.Application.application.child_exit()
314 def keepalive_loop(self, session):
315 keepalive = self.controller.keepalive
317 while session.state == osrf.const.OSRF_APP_SESSION_CONNECTED:
320 session.wait(keepalive)
323 if session.state == osrf.const.OSRF_APP_SESSION_DISCONNECTED:
324 osrf.log.log_internal("client sent disconnect, exiting keepalive")
327 if (end - start) >= keepalive: # exceeded keepalive timeout
329 osrf.log.log_info("No request was received in %d seconds, exiting stateful session" % int(keepalive));
333 osrf.net_obj.NetworkObject.osrfConnectStatus({
334 'status' : 'Disconnected on timeout',
335 'statusCode': osrf.const.OSRF_STATUS_TIMEOUT
343 def send_status(self):
344 ''' Informs the controller that we are done processing this request '''
345 fcntl.lockf(self.controller.write_status.fileno(), fcntl.LOCK_EX)
347 self.controller.write_status.sendall(str(self.pid).rjust(SIZE_PAD))
349 fcntl.lockf(self.controller.write_status.fileno(), fcntl.LOCK_UN)
352 ''' Connects the opensrf xmpp handle '''
353 osrf.net.clear_network_handle()
354 osrf.system.System.net_connect(
355 resource = '%s_drone' % self.controller.service,
356 service = self.controller.service
358 osrf.app.Application.application.child_init()