You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
361 lines
12 KiB
Python
361 lines
12 KiB
Python
# Copyright 2017, David Wilson
|
|
#
|
|
# Redistribution and use in source and binary forms, with or without
|
|
# modification, are permitted provided that the following conditions are met:
|
|
#
|
|
# 1. Redistributions of source code must retain the above copyright notice,
|
|
# this list of conditions and the following disclaimer.
|
|
#
|
|
# 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
# this list of conditions and the following disclaimer in the documentation
|
|
# and/or other materials provided with the distribution.
|
|
#
|
|
# 3. Neither the name of the copyright holder nor the names of its contributors
|
|
# may be used to endorse or promote products derived from this software without
|
|
# specific prior written permission.
|
|
#
|
|
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
|
|
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
# POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
import pprint
|
|
import sys
|
|
import threading
|
|
|
|
import mitogen.core
|
|
import mitogen.master
|
|
from mitogen.core import LOG
|
|
|
|
|
|
class Policy(object):
|
|
"""
|
|
Base security policy.
|
|
"""
|
|
def is_authorized(self, service, msg):
|
|
raise NotImplementedError()
|
|
|
|
|
|
class AllowAny(Policy):
|
|
def is_authorized(self, service, msg):
|
|
return True
|
|
|
|
|
|
class AllowParents(Policy):
|
|
def is_authorized(self, service, msg):
|
|
return (msg.auth_id in mitogen.parent_ids or
|
|
msg.auth_id == mitogen.context_id)
|
|
|
|
|
|
def validate_arg_spec(spec, args):
|
|
for name in spec:
|
|
try:
|
|
obj = args[name]
|
|
except KeyError:
|
|
raise mitogen.core.CallError(
|
|
'Required argument %r missing.' % (name,)
|
|
)
|
|
|
|
if not isinstance(obj, spec[name]):
|
|
raise mitogen.core.CallError(
|
|
'Argument %r type incorrect, got %r, expected %r' % (
|
|
name,
|
|
type(obj),
|
|
spec[name]
|
|
)
|
|
)
|
|
|
|
|
|
def arg_spec(spec):
|
|
"""
|
|
Annotate a method as requiring arguments with a specific type. This only
|
|
validates required arguments. For optional arguments, write a manual check
|
|
within the function.
|
|
|
|
::
|
|
|
|
@mitogen.service.arg_spec({
|
|
'path': str
|
|
})
|
|
def fetch_path(self, path, optional=None):
|
|
...
|
|
|
|
:param dict spec:
|
|
Mapping from argument name to expected type.
|
|
"""
|
|
def wrapper(func):
|
|
func.mitogen_service__arg_spec = spec
|
|
return func
|
|
return wrapper
|
|
|
|
|
|
def expose(policy):
|
|
"""
|
|
Annotate a method to permit access to contexts matching an authorization
|
|
policy. The annotation may be specified multiple times. Methods lacking any
|
|
authorization policy are not accessible.
|
|
|
|
::
|
|
|
|
@mitogen.service.expose(policy=mitogen.service.AllowParents())
|
|
def unsafe_operation(self):
|
|
...
|
|
|
|
:param mitogen.service.Policy policy:
|
|
The policy to require.
|
|
"""
|
|
def wrapper(func):
|
|
func.mitogen_service__policies = (
|
|
[policy] +
|
|
getattr(func, 'mitogen_service__policies', [])
|
|
)
|
|
return func
|
|
return wrapper
|
|
|
|
|
|
class Service(object):
|
|
#: Sentinel object to suppress reply generation, since returning ``None``
|
|
#: will trigger a response message containing the pickled ``None``.
|
|
NO_REPLY = object()
|
|
|
|
#: If ``None``, a handle is dynamically allocated, otherwise the fixed
|
|
#: integer handle to use.
|
|
handle = None
|
|
max_message_size = 0
|
|
|
|
def __init__(self, router):
|
|
self.router = router
|
|
self.recv = mitogen.core.Receiver(router, self.handle)
|
|
self.recv.service = self
|
|
self.handle = self.recv.handle
|
|
self.running = True
|
|
|
|
def __repr__(self):
|
|
return '%s.%s()' % (
|
|
self.__class__.__module__,
|
|
self.__class__.__name__,
|
|
)
|
|
|
|
def on_shutdown(self):
|
|
"""
|
|
Called by Pool.shutdown() once the last worker thread has exitted.
|
|
"""
|
|
|
|
def dispatch(self, args, msg):
|
|
raise NotImplementedError()
|
|
|
|
def _validate_message(self, msg):
|
|
if len(msg.data) > self.max_message_size:
|
|
raise mitogen.core.CallError('Message size exceeded.')
|
|
|
|
pair = msg.unpickle(throw=False)
|
|
if not (isinstance(pair, tuple) and
|
|
len(pair) == 2 and
|
|
isinstance(pair[0], basestring)):
|
|
raise mitogen.core.CallError('Invalid message format.')
|
|
|
|
method_name, kwargs = pair
|
|
method = getattr(self, method_name, None)
|
|
if method is None:
|
|
raise mitogen.core.CallError('No such method exists.')
|
|
|
|
policies = getattr(method, 'mitogen_service__policies', None)
|
|
if not policies:
|
|
raise mitogen.core.CallError('Method has no policies set.')
|
|
|
|
if not all(p.is_authorized(self, msg) for p in policies):
|
|
raise mitogen.core.CallError('Unauthorized')
|
|
|
|
required = getattr(method, 'mitogen_service__arg_spec', {})
|
|
validate_arg_spec(required, kwargs)
|
|
return method_name, kwargs
|
|
|
|
def _on_receive_message(self, msg):
|
|
method_name, kwargs = self._validate_message(msg)
|
|
method = getattr(self, method_name)
|
|
if 'msg' in method.func_code.co_varnames:
|
|
kwargs['msg'] = msg # TODO: hack
|
|
return method(**kwargs)
|
|
|
|
def on_receive_message(self, msg):
|
|
try:
|
|
response = self._on_receive_message(msg)
|
|
if response is not self.NO_REPLY:
|
|
msg.reply(response)
|
|
except mitogen.core.CallError:
|
|
e = sys.exc_info()[1]
|
|
LOG.warning('%r: call error: %s: %s', self, msg, e)
|
|
msg.reply(e)
|
|
except Exception:
|
|
LOG.exception('While invoking %r.dispatch()', self)
|
|
e = sys.exc_info()[1]
|
|
msg.reply(mitogen.core.CallError(e))
|
|
|
|
|
|
class DeduplicatingService(Service):
|
|
"""
|
|
A service that deduplicates and caches expensive responses. Requests are
|
|
deduplicated according to a customizable key, and the single expensive
|
|
response is broadcast to all requestors.
|
|
|
|
A side effect of this class is that processing of the single response is
|
|
always serialized according to the result of :py:meth:`key_from_request`.
|
|
|
|
Only one pool thread is blocked during generation of the response,
|
|
regardless of the number of requestors.
|
|
"""
|
|
def __init__(self, router):
|
|
super(DeduplicatingService, self).__init__(router)
|
|
self._responses = {}
|
|
self._waiters = {}
|
|
self._lock = threading.Lock()
|
|
|
|
def key_from_request(self, method_name, kwargs):
|
|
"""
|
|
Generate a deduplication key from the request. The default
|
|
implementation returns a string based on a stable representation of the
|
|
input dictionary generated by :py:func:`pprint.pformat`.
|
|
"""
|
|
return pprint.pformat((method_name, kwargs))
|
|
|
|
def get_response(self, args):
|
|
raise NotImplementedError()
|
|
|
|
def _produce_response(self, key, response):
|
|
self._lock.acquire()
|
|
try:
|
|
assert key not in self._responses
|
|
assert key in self._waiters
|
|
self._responses[key] = response
|
|
for msg in self._waiters.pop(key):
|
|
msg.reply(response)
|
|
finally:
|
|
self._lock.release()
|
|
|
|
def _on_receive_message(self, msg):
|
|
method_name, kwargs = self._validate_message(msg)
|
|
key = self.key_from_request(method_name, kwargs)
|
|
|
|
self._lock.acquire()
|
|
try:
|
|
if key in self._responses:
|
|
return self._responses[key]
|
|
|
|
if key in self._waiters:
|
|
self._waiters[key].append(msg)
|
|
return self.NO_REPLY
|
|
|
|
self._waiters[key] = [msg]
|
|
finally:
|
|
self._lock.release()
|
|
|
|
# I'm the unlucky thread that must generate the response.
|
|
try:
|
|
response = getattr(self, method_name)(**kwargs)
|
|
self._produce_response(key, response)
|
|
except mitogen.core.CallError:
|
|
e = sys.exc_info()[1]
|
|
self._produce_response(key, e)
|
|
except Exception:
|
|
e = sys.exc_info()[1]
|
|
self._produce_response(key, mitogen.core.CallError(e))
|
|
|
|
return self.NO_REPLY
|
|
|
|
|
|
class Pool(object):
|
|
"""
|
|
Manage a pool of at least one thread that will be used to process messages
|
|
for a collection of services.
|
|
|
|
Internally this is implemented by subscribing every :py:class:`Service`'s
|
|
:py:class:`mitogen.core.Receiver` using a single
|
|
:py:class:`mitogen.master.Select`, then arranging for every thread to
|
|
consume messages delivered to that select.
|
|
|
|
In this way the threads are fairly shared by all available services, and no
|
|
resources are dedicated to a single idle service.
|
|
|
|
There is no penalty for exposing large numbers of services; the list of
|
|
exposed services could even be generated dynamically in response to your
|
|
program's configuration or its input data.
|
|
"""
|
|
def __init__(self, router, services, size=1):
|
|
assert size > 0
|
|
self.router = router
|
|
self.services = list(services)
|
|
self.size = size
|
|
self._select = mitogen.master.Select(
|
|
receivers=[
|
|
service.recv
|
|
for service in self.services
|
|
],
|
|
oneshot=False,
|
|
)
|
|
self._threads = []
|
|
for x in xrange(size):
|
|
thread = threading.Thread(
|
|
name='mitogen.service.Pool.%x.worker-%d' % (id(self), x,),
|
|
target=self._worker_main,
|
|
)
|
|
thread.start()
|
|
self._threads.append(thread)
|
|
|
|
def stop(self):
|
|
self._select.close()
|
|
for th in self._threads:
|
|
th.join()
|
|
for service in self.services:
|
|
service.on_shutdown()
|
|
|
|
def _worker_run(self):
|
|
while True:
|
|
try:
|
|
msg = self._select.get()
|
|
except (mitogen.core.ChannelError, mitogen.core.LatchError):
|
|
e = sys.exc_info()[1]
|
|
LOG.info('%r: channel or latch closed, exitting: %s', self, e)
|
|
return
|
|
|
|
service = msg.receiver.service
|
|
try:
|
|
service.on_receive_message(msg)
|
|
except Exception:
|
|
LOG.exception('While handling %r using %r', msg, service)
|
|
|
|
def _worker_main(self):
|
|
try:
|
|
self._worker_run()
|
|
except Exception:
|
|
th = threading.currentThread()
|
|
LOG.exception('%r: worker %r crashed', self, th.name)
|
|
raise
|
|
|
|
def __repr__(self):
|
|
th = threading.currentThread()
|
|
return 'mitogen.service.Pool(%#x, size=%d, th=%r)' % (
|
|
id(self),
|
|
self.size,
|
|
th.name,
|
|
)
|
|
|
|
|
|
def call_async(context, handle, method, kwargs):
|
|
LOG.debug('service.call_async(%r, %r, %r, %r)',
|
|
context, handle, method, kwargs)
|
|
pair = (method, kwargs)
|
|
msg = mitogen.core.Message.pickled(pair, handle=handle)
|
|
return context.send_async(msg)
|
|
|
|
|
|
def call(context, handle, method, kwargs):
|
|
recv = call_async(context, handle, method, kwargs)
|
|
return recv.get().unpickle()
|