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# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Tests for implementations of L{IHostnameResolver} and their interactions with
reactor implementations.
"""
from collections import defaultdict
from socket import (
AF_INET,
AF_INET6,
AF_UNSPEC,
EAI_NONAME,
IPPROTO_TCP,
SOCK_DGRAM,
SOCK_STREAM,
gaierror,
getaddrinfo,
)
from threading import Lock, local
from zope.interface import implementer
from zope.interface.verify import verifyObject
from twisted._threads import LockWorker, Team, createMemoryWorker
from twisted.internet._resolver import (
ComplexResolverSimplifier,
GAIResolver,
SimpleResolverComplexifier,
)
from twisted.internet.address import IPv4Address, IPv6Address
from twisted.internet.base import PluggableResolverMixin, ReactorBase
from twisted.internet.defer import Deferred
from twisted.internet.error import DNSLookupError
from twisted.internet.interfaces import (
IHostnameResolver,
IReactorPluggableNameResolver,
IResolutionReceiver,
IResolverSimple,
)
from twisted.python.threadpool import ThreadPool
from twisted.trial.unittest import SynchronousTestCase as UnitTest
class DeterministicThreadPool(ThreadPool):
"""
Create a deterministic L{ThreadPool} object.
"""
def __init__(self, team):
"""
Create a L{DeterministicThreadPool} from a L{Team}.
"""
self.min = 1
self.max = 1
self.name = None
self.threads = []
self._team = team
def deterministicPool():
"""
Create a deterministic threadpool.
@return: 2-tuple of L{ThreadPool}, 0-argument C{work} callable; when
C{work} is called, do the work.
"""
worker, doer = createMemoryWorker()
return (
DeterministicThreadPool(
Team(LockWorker(Lock(), local()), (lambda: worker), lambda: None)
),
doer,
)
def deterministicReactorThreads():
"""
Create a deterministic L{IReactorThreads}
@return: a 2-tuple consisting of an L{IReactorThreads}-like object and a
0-argument callable that will perform one unit of work invoked via that
object's C{callFromThread} method.
"""
worker, doer = createMemoryWorker()
class CFT:
def callFromThread(self, f, *a, **k):
worker.do(lambda: f(*a, **k))
return CFT(), doer
class FakeAddrInfoGetter:
"""
Test object implementing getaddrinfo.
"""
def __init__(self):
"""
Create a L{FakeAddrInfoGetter}.
"""
self.calls = []
self.results = defaultdict(list)
def getaddrinfo(self, host, port, family=0, socktype=0, proto=0, flags=0):
"""
Mock for L{socket.getaddrinfo}.
@param host: see L{socket.getaddrinfo}
@param port: see L{socket.getaddrinfo}
@param family: see L{socket.getaddrinfo}
@param socktype: see L{socket.getaddrinfo}
@param proto: see L{socket.getaddrinfo}
@param flags: see L{socket.getaddrinfo}
@return: L{socket.getaddrinfo}
"""
self.calls.append((host, port, family, socktype, proto, flags))
results = self.results[host]
if results:
return results
else:
raise gaierror(EAI_NONAME, "nodename nor servname provided, or not known")
def addResultForHost(
self,
host,
sockaddr,
family=AF_INET,
socktype=SOCK_STREAM,
proto=IPPROTO_TCP,
canonname=b"",
):
"""
Add a result for a given hostname. When this hostname is resolved, the
result will be a L{list} of all results C{addResultForHost} has been
called with using that hostname so far.
@param host: The hostname to give this result for. This will be the
next result from L{FakeAddrInfoGetter.getaddrinfo} when passed this
host.
@type canonname: native L{str}
@param sockaddr: The resulting socket address; should be a 2-tuple for
IPv4 or a 4-tuple for IPv6.
@param family: An C{AF_*} constant that will be returned from
C{getaddrinfo}.
@param socktype: A C{SOCK_*} constant that will be returned from
C{getaddrinfo}.
@param proto: An C{IPPROTO_*} constant that will be returned from
C{getaddrinfo}.
@param canonname: A canonical name that will be returned from
C{getaddrinfo}.
@type canonname: native L{str}
"""
self.results[host].append((family, socktype, proto, canonname, sockaddr))
@implementer(IResolutionReceiver)
class ResultHolder:
"""
A resolution receiver which holds onto the results it received.
"""
_started = False
_ended = False
def __init__(self, testCase):
"""
Create a L{ResultHolder} with a L{UnitTest}.
"""
self._testCase = testCase
def resolutionBegan(self, hostResolution):
"""
Hostname resolution began.
@param hostResolution: see L{IResolutionReceiver}
"""
self._started = True
self._resolution = hostResolution
self._addresses = []
def addressResolved(self, address):
"""
An address was resolved.
@param address: see L{IResolutionReceiver}
"""
self._addresses.append(address)
def resolutionComplete(self):
"""
Hostname resolution is complete.
"""
self._ended = True
class HelperTests(UnitTest):
"""
Tests for error cases of helpers used in this module.
"""
def test_logErrorsInThreads(self):
"""
L{DeterministicThreadPool} will log any exceptions that its "thread"
workers encounter.
"""
self.pool, self.doThreadWork = deterministicPool()
def divideByZero():
return 1 / 0
self.pool.callInThread(divideByZero)
self.doThreadWork()
self.assertEqual(len(self.flushLoggedErrors(ZeroDivisionError)), 1)
class HostnameResolutionTests(UnitTest):
"""
Tests for hostname resolution.
"""
def setUp(self):
"""
Set up a L{GAIResolver}.
"""
self.pool, self.doThreadWork = deterministicPool()
self.reactor, self.doReactorWork = deterministicReactorThreads()
self.getter = FakeAddrInfoGetter()
self.resolver = GAIResolver(
self.reactor, lambda: self.pool, self.getter.getaddrinfo
)
def test_resolveOneHost(self):
"""
Resolving an individual hostname that results in one address from
getaddrinfo results in a single call each to C{resolutionBegan},
C{addressResolved}, and C{resolutionComplete}.
"""
receiver = ResultHolder(self)
self.getter.addResultForHost("sample.example.com", ("4.3.2.1", 0))
resolution = self.resolver.resolveHostName(receiver, "sample.example.com")
self.assertIs(receiver._resolution, resolution)
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.doThreadWork()
self.doReactorWork()
self.assertEqual(receiver._ended, True)
self.assertEqual(receiver._addresses, [IPv4Address("TCP", "4.3.2.1", 0)])
def test_resolveOneIPv6Host(self):
"""
Resolving an individual hostname that results in one address from
getaddrinfo results in a single call each to C{resolutionBegan},
C{addressResolved}, and C{resolutionComplete}; C{addressResolved} will
receive an L{IPv6Address}.
"""
receiver = ResultHolder(self)
flowInfo = 1
scopeID = 2
self.getter.addResultForHost(
"sample.example.com", ("::1", 0, flowInfo, scopeID), family=AF_INET6
)
resolution = self.resolver.resolveHostName(receiver, "sample.example.com")
self.assertIs(receiver._resolution, resolution)
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.doThreadWork()
self.doReactorWork()
self.assertEqual(receiver._ended, True)
self.assertEqual(
receiver._addresses, [IPv6Address("TCP", "::1", 0, flowInfo, scopeID)]
)
def test_gaierror(self):
"""
Resolving a hostname that results in C{getaddrinfo} raising a
L{gaierror} will result in the L{IResolutionReceiver} receiving a call
to C{resolutionComplete} with no C{addressResolved} calls in between;
no failure is logged.
"""
receiver = ResultHolder(self)
resolution = self.resolver.resolveHostName(receiver, "sample.example.com")
self.assertIs(receiver._resolution, resolution)
self.doThreadWork()
self.doReactorWork()
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, True)
self.assertEqual(receiver._addresses, [])
def _resolveOnlyTest(self, addrTypes, expectedAF):
"""
Verify that the given set of address types results in the given C{AF_}
constant being passed to C{getaddrinfo}.
@param addrTypes: iterable of L{IAddress} implementers
@param expectedAF: an C{AF_*} constant
"""
receiver = ResultHolder(self)
resolution = self.resolver.resolveHostName(
receiver, "sample.example.com", addressTypes=addrTypes
)
self.assertIs(receiver._resolution, resolution)
self.doThreadWork()
self.doReactorWork()
host, port, family, socktype, proto, flags = self.getter.calls[0]
self.assertEqual(family, expectedAF)
def test_resolveOnlyIPv4(self):
"""
When passed an C{addressTypes} parameter containing only
L{IPv4Address}, L{GAIResolver} will pass C{AF_INET} to C{getaddrinfo}.
"""
self._resolveOnlyTest([IPv4Address], AF_INET)
def test_resolveOnlyIPv6(self):
"""
When passed an C{addressTypes} parameter containing only
L{IPv6Address}, L{GAIResolver} will pass C{AF_INET6} to C{getaddrinfo}.
"""
self._resolveOnlyTest([IPv6Address], AF_INET6)
def test_resolveBoth(self):
"""
When passed an C{addressTypes} parameter containing both L{IPv4Address}
and L{IPv6Address} (or the default of C{None}, which carries the same
meaning), L{GAIResolver} will pass C{AF_UNSPEC} to C{getaddrinfo}.
"""
self._resolveOnlyTest([IPv4Address, IPv6Address], AF_UNSPEC)
self._resolveOnlyTest(None, AF_UNSPEC)
def test_transportSemanticsToSocketType(self):
"""
When passed a C{transportSemantics} paramter, C{'TCP'} (the value
present in L{IPv4Address.type} to indicate a stream transport) maps to
C{SOCK_STREAM} and C{'UDP'} maps to C{SOCK_DGRAM}.
"""
receiver = ResultHolder(self)
self.resolver.resolveHostName(receiver, "example.com", transportSemantics="TCP")
receiver2 = ResultHolder(self)
self.resolver.resolveHostName(
receiver2, "example.com", transportSemantics="UDP"
)
self.doThreadWork()
self.doReactorWork()
self.doThreadWork()
self.doReactorWork()
host, port, family, socktypeT, proto, flags = self.getter.calls[0]
host, port, family, socktypeU, proto, flags = self.getter.calls[1]
self.assertEqual(socktypeT, SOCK_STREAM)
self.assertEqual(socktypeU, SOCK_DGRAM)
def test_socketTypeToAddressType(self):
"""
When L{GAIResolver} receives a C{SOCK_DGRAM} result from
C{getaddrinfo}, it returns a C{'TCP'} L{IPv4Address} or L{IPv6Address};
if it receives C{SOCK_STREAM} then it returns a C{'UDP'} type of same.
"""
receiver = ResultHolder(self)
flowInfo = 1
scopeID = 2
for socktype in SOCK_STREAM, SOCK_DGRAM:
self.getter.addResultForHost(
"example.com",
("::1", 0, flowInfo, scopeID),
family=AF_INET6,
socktype=socktype,
)
self.getter.addResultForHost(
"example.com", ("127.0.0.3", 0), family=AF_INET, socktype=socktype
)
self.resolver.resolveHostName(receiver, "example.com")
self.doThreadWork()
self.doReactorWork()
stream4, stream6, dgram4, dgram6 = receiver._addresses
self.assertEqual(stream4.type, "TCP")
self.assertEqual(stream6.type, "TCP")
self.assertEqual(dgram4.type, "UDP")
self.assertEqual(dgram6.type, "UDP")
@implementer(IResolverSimple)
class SillyResolverSimple:
"""
Trivial implementation of L{IResolverSimple}
"""
def __init__(self):
"""
Create a L{SillyResolverSimple} with a queue of requests it is working
on.
"""
self._requests = []
def getHostByName(self, name, timeout=()):
"""
Implement L{IResolverSimple.getHostByName}.
@param name: see L{IResolverSimple.getHostByName}.
@param timeout: see L{IResolverSimple.getHostByName}.
@return: see L{IResolverSimple.getHostByName}.
"""
self._requests.append(Deferred())
return self._requests[-1]
class LegacyCompatibilityTests(UnitTest):
"""
Older applications may supply an object to the reactor via
C{installResolver} that only provides L{IResolverSimple}.
L{SimpleResolverComplexifier} is a wrapper for an L{IResolverSimple}.
"""
def test_success(self):
"""
L{SimpleResolverComplexifier} translates C{resolveHostName} into
L{IResolutionReceiver.addressResolved}.
"""
simple = SillyResolverSimple()
complex = SimpleResolverComplexifier(simple)
receiver = ResultHolder(self)
self.assertEqual(receiver._started, False)
complex.resolveHostName(receiver, "example.com")
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.assertEqual(receiver._addresses, [])
simple._requests[0].callback("192.168.1.1")
self.assertEqual(receiver._addresses, [IPv4Address("TCP", "192.168.1.1", 0)])
self.assertEqual(receiver._ended, True)
def test_failure(self):
"""
L{SimpleResolverComplexifier} translates a known error result from
L{IResolverSimple.resolveHostName} into an empty result.
"""
simple = SillyResolverSimple()
complex = SimpleResolverComplexifier(simple)
receiver = ResultHolder(self)
self.assertEqual(receiver._started, False)
complex.resolveHostName(receiver, "example.com")
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.assertEqual(receiver._addresses, [])
simple._requests[0].errback(DNSLookupError("nope"))
self.assertEqual(receiver._ended, True)
self.assertEqual(receiver._addresses, [])
def test_error(self):
"""
L{SimpleResolverComplexifier} translates an unknown error result from
L{IResolverSimple.resolveHostName} into an empty result and a logged
error.
"""
simple = SillyResolverSimple()
complex = SimpleResolverComplexifier(simple)
receiver = ResultHolder(self)
self.assertEqual(receiver._started, False)
complex.resolveHostName(receiver, "example.com")
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.assertEqual(receiver._addresses, [])
simple._requests[0].errback(ZeroDivisionError("zow"))
self.assertEqual(len(self.flushLoggedErrors(ZeroDivisionError)), 1)
self.assertEqual(receiver._ended, True)
self.assertEqual(receiver._addresses, [])
def test_simplifier(self):
"""
L{ComplexResolverSimplifier} translates an L{IHostnameResolver} into an
L{IResolverSimple} for applications that still expect the old
interfaces to be in place.
"""
self.pool, self.doThreadWork = deterministicPool()
self.reactor, self.doReactorWork = deterministicReactorThreads()
self.getter = FakeAddrInfoGetter()
self.resolver = GAIResolver(
self.reactor, lambda: self.pool, self.getter.getaddrinfo
)
simpleResolver = ComplexResolverSimplifier(self.resolver)
self.getter.addResultForHost("example.com", ("192.168.3.4", 4321))
success = simpleResolver.getHostByName("example.com")
failure = simpleResolver.getHostByName("nx.example.com")
self.doThreadWork()
self.doReactorWork()
self.doThreadWork()
self.doReactorWork()
self.assertEqual(self.failureResultOf(failure).type, DNSLookupError)
self.assertEqual(self.successResultOf(success), "192.168.3.4")
def test_portNumber(self):
"""
L{SimpleResolverComplexifier} preserves the C{port} argument passed to
C{resolveHostName} in its returned addresses.
"""
simple = SillyResolverSimple()
complex = SimpleResolverComplexifier(simple)
receiver = ResultHolder(self)
complex.resolveHostName(receiver, "example.com", 4321)
self.assertEqual(receiver._started, True)
self.assertEqual(receiver._ended, False)
self.assertEqual(receiver._addresses, [])
simple._requests[0].callback("192.168.1.1")
self.assertEqual(receiver._addresses, [IPv4Address("TCP", "192.168.1.1", 4321)])
self.assertEqual(receiver._ended, True)
class JustEnoughReactor(ReactorBase):
"""
Just enough subclass implementation to be a valid L{ReactorBase} subclass.
"""
def installWaker(self):
"""
Do nothing.
"""
class ReactorInstallationTests(UnitTest):
"""
Tests for installing old and new resolvers onto a
L{PluggableResolverMixin} and L{ReactorBase} (from which all of Twisted's
reactor implementations derive).
"""
def test_interfaceCompliance(self):
"""
L{PluggableResolverMixin} (and its subclasses) implement both
L{IReactorPluggableNameResolver} and L{IReactorPluggableResolver}.
"""
reactor = PluggableResolverMixin()
verifyObject(IReactorPluggableNameResolver, reactor)
verifyObject(IResolverSimple, reactor.resolver)
verifyObject(IHostnameResolver, reactor.nameResolver)
def test_installingOldStyleResolver(self):
"""
L{PluggableResolverMixin} will wrap an L{IResolverSimple} in a
complexifier.
"""
reactor = PluggableResolverMixin()
it = SillyResolverSimple()
verifyObject(IResolverSimple, reactor.installResolver(it))
self.assertIsInstance(reactor.nameResolver, SimpleResolverComplexifier)
self.assertIs(reactor.nameResolver._simpleResolver, it)
def test_defaultToGAIResolver(self):
"""
L{ReactorBase} defaults to using a L{GAIResolver}.
"""
reactor = JustEnoughReactor()
self.assertIsInstance(reactor.nameResolver, GAIResolver)
self.assertIs(reactor.nameResolver._getaddrinfo, getaddrinfo)
self.assertIsInstance(reactor.resolver, ComplexResolverSimplifier)
self.assertIs(reactor.nameResolver._reactor, reactor)
self.assertIs(reactor.resolver._nameResolver, reactor.nameResolver)
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