/brz/remove-bazaar

# Copyright (C) 2010, 2011 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

import errno

import socket

import SocketServer

import threading

from bzrlib import (

    osutils,

    tests,

    )

from bzrlib.tests import test_server

from bzrlib.tests.scenarios import load_tests_apply_scenarios

load_tests = load_tests_apply_scenarios

class TCPClient(object):

    def __init__(self):

        self.sock = None

    def connect(self, addr):

        if self.sock is not None:

            raise AssertionError('Already connected to %r'

                                 % (self.sock.getsockname(),))

        self.sock = osutils.connect_socket(addr)

    def disconnect(self):

        if self.sock is not None:

            try:

                self.sock.shutdown(socket.SHUT_RDWR)

                self.sock.close()

            except socket.error, e:

                if e[0] in (errno.EBADF, errno.ENOTCONN):

                    # Right, the socket is already down

                    pass

                else:

                    raise

            self.sock = None

    def write(self, s):

        return self.sock.sendall(s)

    def read(self, bufsize=4096):

        return self.sock.recv(bufsize)

class TCPConnectionHandler(SocketServer.StreamRequestHandler):

    def handle(self):

        self.done = False

        self.handle_connection()

        while not self.done:

            self.handle_connection()

    def handle_connection(self):

        req = self.rfile.readline()

        if not req:

            self.done = True

        elif req == 'ping\n':

            self.wfile.write('pong\n')

        else:

            raise ValueError('[%s] not understood' % req)

class TestTCPServerInAThread(tests.TestCase):

    scenarios = [ 

        (name, {'server_class': getattr(test_server, name)})

        for name in

        ('TestingTCPServer', 'TestingThreadingTCPServer')]

    def get_server(self, server_class=None, connection_handler_class=None):

        if server_class is not None:

            self.server_class = server_class

        if connection_handler_class is None:

            connection_handler_class = TCPConnectionHandler

        server =  test_server.TestingTCPServerInAThread(

            ('localhost', 0), self.server_class, connection_handler_class)

        server.start_server()

        self.addCleanup(server.stop_server)

        return server

    def get_client(self):

        client = TCPClient()

        self.addCleanup(client.disconnect)

        return client

    def get_server_connection(self, server, conn_rank):

        return server.server.clients[conn_rank]

    def assertClientAddr(self, client, server, conn_rank):

        conn = self.get_server_connection(server, conn_rank)

        self.assertEquals(client.sock.getsockname(), conn[1])

    def test_start_stop(self):

        server = self.get_server()

        client = self.get_client()

        server.stop_server()

        # since the server doesn't accept connections anymore attempting to

        # connect should fail

        client = self.get_client()

        self.assertRaises(socket.error,

                          client.connect, (server.host, server.port))

    def test_client_talks_server_respond(self):

        server = self.get_server()

        client = self.get_client()

        client.connect((server.host, server.port))

        self.assertIs(None, client.write('ping\n'))

        resp = client.read()

        self.assertClientAddr(client, server, 0)

        self.assertEquals('pong\n', resp)

    def test_server_fails_to_start(self):

        class CantStart(Exception):

            pass

        class CantStartServer(test_server.TestingTCPServer):

            def server_bind(self):

                raise CantStart()

        # The exception is raised in the main thread

        self.assertRaises(CantStart,

                          self.get_server, server_class=CantStartServer)

    def test_server_fails_while_serving_or_stopping(self):

        class CantConnect(Exception):

            pass

        class FailingConnectionHandler(TCPConnectionHandler):

            def handle(self):

                raise CantConnect()

        server = self.get_server(

            connection_handler_class=FailingConnectionHandler)

        # The server won't fail until a client connect

        client = self.get_client()

        client.connect((server.host, server.port))

        try:

            # Now we must force the server to answer by sending the request and

            # waiting for some answer. But since we don't control when the

            # server thread will be given cycles, we don't control either

            # whether our reads or writes may hang.

            client.sock.settimeout(0.1)

            client.write('ping\n')

            client.read()

        except socket.error:

            pass

        # Now the server has raised the exception in its own thread

        self.assertRaises(CantConnect, server.stop_server)

    def test_server_crash_while_responding(self):

        # We want to ensure the exception has been caught

        caught = threading.Event()

        caught.clear()

        # The thread that will serve the client, this needs to be an attribute

        # so the handler below can modify it when it's executed (it's

        # instantiated when the request is processed)

        self.connection_thread = None

        class FailToRespond(Exception):

            pass

        class FailingDuringResponseHandler(TCPConnectionHandler):

            def handle_connection(request):

                req = request.rfile.readline()

                # Capture the thread and make it use 'caught' so we can wait on

                # the even that will be set when the exception is caught. We

                # also capture the thread to know where to look.

                self.connection_thread = threading.currentThread()

                self.connection_thread.set_sync_event(caught)

                raise FailToRespond()

        server = self.get_server(

            connection_handler_class=FailingDuringResponseHandler)

        client = self.get_client()

        client.connect((server.host, server.port))

        client.write('ping\n')

        # Wait for the exception to be caught

        caught.wait()

        # Check that the connection thread did catch the exception,

        # http://pad.lv/869366 was wrongly checking the server thread which

        # works for TestingTCPServer where the connection is handled in the

        # same thread than the server one but is racy for

        # TestingThreadingTCPServer where the server thread may be in a

        # blocking accept() call (or not).

        try:

            self.connection_thread.pending_exception()

        except FailToRespond:

            # Great, the test succeeded

            pass

        else:

            # If the exception is not in the connection thread anymore, it's in

            # the server's one. 

            server.server.stopped.wait()

            # The exception is available now

            self.assertRaises(FailToRespond, server.pending_exception)

    def test_exception_swallowed_while_serving(self):

        # We need to ensure the exception has been caught

        caught = threading.Event()

        caught.clear()

        # The thread that will serve the client, this needs to be an attribute

        # so the handler below can access it when it's executed (it's

        # instantiated when the request is processed)

        self.connection_thread = None

        class CantServe(Exception):

            pass

        class FailingWhileServingConnectionHandler(TCPConnectionHandler):

            def handle(request):

                # Capture the thread and make it use 'caught' so we can wait on

                # the even that will be set when the exception is caught. We

                # also capture the thread to know where to look.

                self.connection_thread = threading.currentThread()

                self.connection_thread.set_sync_event(caught)

                raise CantServe()

        server = self.get_server(

            connection_handler_class=FailingWhileServingConnectionHandler)

        # Install the exception swallower

        server.set_ignored_exceptions(CantServe)

        client = self.get_client()

        # Connect to the server so the exception is raised there

        client.connect((server.host, server.port))

        # Wait for the exception to be caught

        caught.wait()

        # The connection wasn't served properly but the exception should have

        # been swallowed (see test_server_crash_while_responding remark about

        # http://pad.lv/869366 explaining why we can't check the server thread

        # here). More precisely, the exception *has* been caught and captured

        # but it is cleared when joining the thread (or trying to acquire the

        # exception) and as such won't propagate to the server thread.

        self.connection_thread.pending_exception()

        server.pending_exception()