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# Copyright (C) 2006, 2007 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""Server for smart-server protocol."""
import errno
import socket
import threading
from bzrlib.hooks import Hooks
from bzrlib import (
errors,
trace,
transport,
)
from bzrlib.smart.medium import SmartServerSocketStreamMedium
class SmartTCPServer(object):
"""Listens on a TCP socket and accepts connections from smart clients.
Each connection will be served by a SmartServerSocketStreamMedium running in
a thread.
hooks: An instance of SmartServerHooks.
"""
def __init__(self, backing_transport, host='127.0.0.1', port=0):
"""Construct a new server.
To actually start it running, call either start_background_thread or
serve.
:param host: Name of the interface to listen on.
:param port: TCP port to listen on, or 0 to allocate a transient port.
"""
# let connections timeout so that we get a chance to terminate
# Keep a reference to the exceptions we want to catch because the socket
# module's globals get set to None during interpreter shutdown.
from socket import timeout as socket_timeout
from socket import error as socket_error
self._socket_error = socket_error
self._socket_timeout = socket_timeout
self._server_socket = socket.socket()
self._server_socket.bind((host, port))
self._sockname = self._server_socket.getsockname()
self.port = self._sockname[1]
self._server_socket.listen(1)
self._server_socket.settimeout(1)
self.backing_transport = backing_transport
self._started = threading.Event()
self._stopped = threading.Event()
def serve(self):
self._should_terminate = False
# for hooks we are letting code know that a server has started (and
# later stopped).
# There are three interesting urls:
# The URL the server can be contacted on. (e.g. bzr://host/)
# The URL that a commit done on the same machine as the server will
# have within the servers space. (e.g. file:///home/user/source)
# The URL that will be given to other hooks in the same process -
# the URL of the backing transport itself. (e.g. chroot+:///)
# We need all three because:
# * other machines see the first
# * local commits on this machine should be able to be mapped to
# this server
# * commits the server does itself need to be mapped across to this
# server.
# The latter two urls are different aliases to the servers url,
# so we group those in a list - as there might be more aliases
# in the future.
backing_urls = [self.backing_transport.base]
try:
backing_urls.append(self.backing_transport.external_url())
except errors.InProcessTransport:
pass
for hook in SmartTCPServer.hooks['server_started']:
hook(backing_urls, self.get_url())
self._started.set()
try:
try:
while not self._should_terminate:
try:
conn, client_addr = self._server_socket.accept()
except self._socket_timeout:
# just check if we're asked to stop
pass
except self._socket_error, e:
# if the socket is closed by stop_background_thread
# we might get a EBADF here, any other socket errors
# should get logged.
if e.args[0] != errno.EBADF:
trace.warning("listening socket error: %s", e)
else:
self.serve_conn(conn)
except KeyboardInterrupt:
# dont log when CTRL-C'd.
raise
except Exception, e:
trace.error("Unhandled smart server error.")
trace.log_exception_quietly()
raise
finally:
self._stopped.set()
try:
# ensure the server socket is closed.
self._server_socket.close()
except self._socket_error:
# ignore errors on close
pass
for hook in SmartTCPServer.hooks['server_stopped']:
hook(backing_urls, self.get_url())
def get_url(self):
"""Return the url of the server"""
return "bzr://%s:%d/" % self._sockname
def serve_conn(self, conn):
# For WIN32, where the timeout value from the listening socket
# propogates to the newly accepted socket.
conn.setblocking(True)
conn.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
handler = SmartServerSocketStreamMedium(conn, self.backing_transport)
connection_thread = threading.Thread(None, handler.serve, name='smart-server-child')
connection_thread.setDaemon(True)
connection_thread.start()
def start_background_thread(self):
self._started.clear()
self._server_thread = threading.Thread(None,
self.serve,
name='server-' + self.get_url())
self._server_thread.setDaemon(True)
self._server_thread.start()
self._started.wait()
def stop_background_thread(self):
self._stopped.clear()
# tell the main loop to quit on the next iteration.
self._should_terminate = True
# close the socket - gives error to connections from here on in,
# rather than a connection reset error to connections made during
# the period between setting _should_terminate = True and
# the current request completing/aborting. It may also break out the
# main loop if it was currently in accept() (on some platforms).
try:
self._server_socket.close()
except self._socket_error:
# ignore errors on close
pass
if not self._stopped.isSet():
# server has not stopped (though it may be stopping)
# its likely in accept(), so give it a connection
temp_socket = socket.socket()
temp_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
if not temp_socket.connect_ex(self._sockname):
# and close it immediately: we dont choose to send any requests.
temp_socket.close()
self._stopped.wait()
self._server_thread.join()
class SmartServerHooks(Hooks):
"""Hooks for the smart server."""
def __init__(self):
"""Create the default hooks.
These are all empty initially, because by default nothing should get
notified.
"""
Hooks.__init__(self)
# Introduced in 0.16:
# invoked whenever the server starts serving a directory.
# The api signature is (backing urls, public url).
self['server_started'] = []
# Introduced in 0.16:
# invoked whenever the server stops serving a directory.
# The api signature is (backing urls, public url).
self['server_stopped'] = []
SmartTCPServer.hooks = SmartServerHooks()
class SmartTCPServer_for_testing(SmartTCPServer):
"""Server suitable for use by transport tests.
This server is backed by the process's cwd.
"""
def __init__(self):
SmartTCPServer.__init__(self, None)
def get_backing_transport(self, backing_transport_server):
"""Get a backing transport from a server we are decorating."""
return transport.get_transport(backing_transport_server.get_url())
def setUp(self, backing_transport_server=None):
"""Set up server for testing"""
from bzrlib.transport.chroot import ChrootServer
if backing_transport_server is None:
from bzrlib.transport.local import LocalURLServer
backing_transport_server = LocalURLServer()
self.chroot_server = ChrootServer(
self.get_backing_transport(backing_transport_server))
self.chroot_server.setUp()
self.backing_transport = transport.get_transport(
self.chroot_server.get_url())
self.start_background_thread()
def tearDown(self):
self.stop_background_thread()
self.chroot_server.tearDown()
def get_bogus_url(self):
"""Return a URL which will fail to connect"""
return 'bzr://127.0.0.1:1/'
class ReadonlySmartTCPServer_for_testing(SmartTCPServer_for_testing):
"""Get a readonly server for testing."""
def get_backing_transport(self, backing_transport_server):
"""Get a backing transport from a server we are decorating."""
url = 'readonly+' + backing_transport_server.get_url()
return transport.get_transport(url)
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