lbry-sdk/lbry/wallet/rpc/session.py

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# Copyright (c) 2018, Neil Booth
#
# All rights reserved.
#
# The MIT License (MIT)
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
__all__ = ('Connector', 'RPCSession', 'MessageSession', 'Server',
'BatchError')
import asyncio
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from asyncio import Event, CancelledError
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import logging
import time
from contextlib import suppress
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from prometheus_client import Counter, Histogram
from lbry.wallet.tasks import TaskGroup
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from .jsonrpc import Request, JSONRPCConnection, JSONRPCv2, JSONRPC, Batch, Notification
from .jsonrpc import RPCError, ProtocolError
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from .framing import BadMagicError, BadChecksumError, OversizedPayloadError, BitcoinFramer, NewlineFramer
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HISTOGRAM_BUCKETS = (
.005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 60.0, float('inf')
)
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class Connector:
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def __init__(self, session_factory, host=None, port=None, proxy=None,
**kwargs):
self.session_factory = session_factory
self.host = host
self.port = port
self.proxy = proxy
self.loop = kwargs.get('loop', asyncio.get_event_loop())
self.kwargs = kwargs
async def create_connection(self):
"""Initiate a connection."""
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connector = self.proxy or self.loop
return await connector.create_connection(
self.session_factory, self.host, self.port, **self.kwargs)
async def __aenter__(self):
transport, self.protocol = await self.create_connection()
return self.protocol
async def __aexit__(self, exc_type, exc_value, traceback):
await self.protocol.close()
class SessionBase(asyncio.Protocol):
"""Base class of networking sessions.
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There is no client / server distinction other than who initiated
the connection.
To initiate a connection to a remote server pass host, port and
proxy to the constructor, and then call create_connection(). Each
successful call should have a corresponding call to close().
Alternatively if used in a with statement, the connection is made
on entry to the block, and closed on exit from the block.
"""
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max_errors = 10
def __init__(self, *, framer=None, loop=None):
self.framer = framer or self.default_framer()
self.loop = loop or asyncio.get_event_loop()
self.logger = logging.getLogger(self.__class__.__name__)
self.transport = None
# Set when a connection is made
self._address = None
self._proxy_address = None
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# For logger.debug messages
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self.verbosity = 0
# Cleared when the send socket is full
self._can_send = Event()
self._can_send.set()
self._pm_task = None
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self._task_group = TaskGroup(self.loop)
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# Force-close a connection if a send doesn't succeed in this time
self.max_send_delay = 60
# Statistics. The RPC object also keeps its own statistics.
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self.start_time = time.perf_counter()
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self.errors = 0
self.send_count = 0
self.send_size = 0
self.last_send = self.start_time
self.recv_count = 0
self.recv_size = 0
self.last_recv = self.start_time
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self.last_packet_received = self.start_time
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async def _limited_wait(self, secs):
try:
await asyncio.wait_for(self._can_send.wait(), secs)
except asyncio.TimeoutError:
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self.abort()
raise asyncio.TimeoutError(f'task timed out after {secs}s')
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async def _send_message(self, message):
if not self._can_send.is_set():
await self._limited_wait(self.max_send_delay)
if not self.is_closing():
framed_message = self.framer.frame(message)
self.send_size += len(framed_message)
self.send_count += 1
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self.last_send = time.perf_counter()
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if self.verbosity >= 4:
self.logger.debug(f'Sending framed message {framed_message}')
self.transport.write(framed_message)
def _bump_errors(self):
self.errors += 1
if self.errors >= self.max_errors:
# Don't await self.close() because that is self-cancelling
self._close()
def _close(self):
if self.transport:
self.transport.close()
# asyncio framework
def data_received(self, framed_message):
"""Called by asyncio when a message comes in."""
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self.last_packet_received = time.perf_counter()
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if self.verbosity >= 4:
self.logger.debug(f'Received framed message {framed_message}')
self.recv_size += len(framed_message)
self.framer.received_bytes(framed_message)
def pause_writing(self):
"""Transport calls when the send buffer is full."""
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if not self.is_closing():
self._can_send.clear()
self.transport.pause_reading()
def resume_writing(self):
"""Transport calls when the send buffer has room."""
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if not self._can_send.is_set():
self._can_send.set()
self.transport.resume_reading()
def connection_made(self, transport):
"""Called by asyncio when a connection is established.
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Derived classes overriding this method must call this first."""
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self.transport = transport
# This would throw if called on a closed SSL transport. Fixed
# in asyncio in Python 3.6.1 and 3.5.4
peer_address = transport.get_extra_info('peername')
# If the Socks proxy was used then _address is already set to
# the remote address
if self._address:
self._proxy_address = peer_address
else:
self._address = peer_address
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self._pm_task = self.loop.create_task(self._receive_messages())
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def connection_lost(self, exc):
"""Called by asyncio when the connection closes.
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Tear down things done in connection_made."""
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self._address = None
self.transport = None
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self._task_group.cancel()
if self._pm_task:
self._pm_task.cancel()
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# Release waiting tasks
self._can_send.set()
# External API
def default_framer(self):
"""Return a default framer."""
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raise NotImplementedError
def peer_address(self):
"""Returns the peer's address (Python networking address), or None if
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no connection or an error.
This is the result of socket.getpeername() when the connection
was made.
"""
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return self._address
def peer_address_str(self, for_log=True):
"""Returns the peer's IP address and port as a human-readable
string."""
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if not self._address:
return 'unknown'
ip_addr_str, port = self._address[:2]
if ':' in ip_addr_str:
return f'[{ip_addr_str}]:{port}'
else:
return f'{ip_addr_str}:{port}'
def is_closing(self):
"""Return True if the connection is closing."""
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return not self.transport or self.transport.is_closing()
def abort(self):
"""Forcefully close the connection."""
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if self.transport:
self.transport.abort()
# TODO: replace with synchronous_close
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async def close(self, *, force_after=30):
"""Close the connection and return when closed."""
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self._close()
if self._pm_task:
with suppress(CancelledError):
await asyncio.wait([self._pm_task], timeout=force_after)
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self.abort()
await self._pm_task
def synchronous_close(self):
self._close()
if self._pm_task and not self._pm_task.done():
self._pm_task.cancel()
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class MessageSession(SessionBase):
"""Session class for protocols where messages are not tied to responses,
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such as the Bitcoin protocol.
To use as a client (connection-opening) session, pass host, port
and perhaps a proxy.
"""
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async def _receive_messages(self):
while not self.is_closing():
try:
message = await self.framer.receive_message()
except BadMagicError as e:
magic, expected = e.args
self.logger.error(
f'bad network magic: got {magic} expected {expected}, '
f'disconnecting'
)
self._close()
except OversizedPayloadError as e:
command, payload_len = e.args
self.logger.error(
f'oversized payload of {payload_len:,d} bytes to command '
f'{command}, disconnecting'
)
self._close()
except BadChecksumError as e:
payload_checksum, claimed_checksum = e.args
self.logger.warning(
f'checksum mismatch: actual {payload_checksum.hex()} '
f'vs claimed {claimed_checksum.hex()}'
)
self._bump_errors()
else:
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self.last_recv = time.perf_counter()
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self.recv_count += 1
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await self._task_group.add(self._handle_message(message))
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async def _handle_message(self, message):
try:
await self.handle_message(message)
except ProtocolError as e:
self.logger.error(f'{e}')
self._bump_errors()
except CancelledError:
raise
except Exception:
self.logger.exception(f'exception handling {message}')
self._bump_errors()
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# External API
def default_framer(self):
"""Return a bitcoin framer."""
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return BitcoinFramer(bytes.fromhex('e3e1f3e8'), 128_000_000)
async def handle_message(self, message):
"""message is a (command, payload) pair."""
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pass
async def send_message(self, message):
"""Send a message (command, payload) over the network."""
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await self._send_message(message)
class BatchError(Exception):
def __init__(self, request):
self.request = request # BatchRequest object
class BatchRequest:
"""Used to build a batch request to send to the server. Stores
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the
Attributes batch and results are initially None.
Adding an invalid request or notification immediately raises a
ProtocolError.
On exiting the with clause, it will:
1) create a Batch object for the requests in the order they were
added. If the batch is empty this raises a ProtocolError.
2) set the "batch" attribute to be that batch
3) send the batch request and wait for a response
4) raise a ProtocolError if the protocol was violated by the
server. Currently this only happens if it gave more than one
response to any request
5) otherwise there is precisely one response to each Request. Set
the "results" attribute to the tuple of results; the responses
are ordered to match the Requests in the batch. Notifications
do not get a response.
6) if raise_errors is True and any individual response was a JSON
RPC error response, or violated the protocol in some way, a
BatchError exception is raised. Otherwise the caller can be
certain each request returned a standard result.
"""
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def __init__(self, session, raise_errors):
self._session = session
self._raise_errors = raise_errors
self._requests = []
self.batch = None
self.results = None
def add_request(self, method, args=()):
self._requests.append(Request(method, args))
def add_notification(self, method, args=()):
self._requests.append(Notification(method, args))
def __len__(self):
return len(self._requests)
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc_value, traceback):
if exc_type is None:
self.batch = Batch(self._requests)
message, event = self._session.connection.send_batch(self.batch)
await self._session._send_message(message)
await event.wait()
self.results = event.result
if self._raise_errors:
if any(isinstance(item, Exception) for item in event.result):
raise BatchError(self)
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NAMESPACE = "wallet_server"
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class RPCSession(SessionBase):
"""Base class for protocols where a message can lead to a response,
for example JSON RPC."""
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RESPONSE_TIMES = Histogram("response_time", "Response times", namespace=NAMESPACE,
labelnames=("method", "version"), buckets=HISTOGRAM_BUCKETS)
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NOTIFICATION_COUNT = Counter("notification", "Number of notifications sent (for subscriptions)",
namespace=NAMESPACE, labelnames=("method", "version"))
REQUEST_ERRORS_COUNT = Counter(
"request_error", "Number of requests that returned errors", namespace=NAMESPACE,
labelnames=("method", "version")
)
RESET_CONNECTIONS = Counter(
"reset_clients", "Number of reset connections by client version",
namespace=NAMESPACE, labelnames=("version",)
)
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def __init__(self, *, framer=None, loop=None, connection=None):
super().__init__(framer=framer, loop=loop)
self.connection = connection or self.default_connection()
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self.client_version = 'unknown'
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async def _receive_messages(self):
while not self.is_closing():
try:
message = await self.framer.receive_message()
except MemoryError:
self.logger.warning('received oversized message from %s:%s, dropping connection',
self._address[0], self._address[1])
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self.RESET_CONNECTIONS.labels(version=self.client_version).inc()
self._close()
return
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self.last_recv = time.perf_counter()
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self.recv_count += 1
try:
requests = self.connection.receive_message(message)
except ProtocolError as e:
self.logger.debug(f'{e}')
if e.error_message:
await self._send_message(e.error_message)
if e.code == JSONRPC.PARSE_ERROR:
self.max_errors = 0
self._bump_errors()
else:
for request in requests:
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await self._task_group.add(self._handle_request(request))
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async def _handle_request(self, request):
start = time.perf_counter()
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try:
result = await self.handle_request(request)
except (ProtocolError, RPCError) as e:
result = e
except CancelledError:
raise
except Exception:
self.logger.exception(f'exception handling {request}')
result = RPCError(JSONRPC.INTERNAL_ERROR,
'internal server error')
if isinstance(request, Request):
message = request.send_result(result)
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self.RESPONSE_TIMES.labels(
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method=request.method,
version=self.client_version
).observe(time.perf_counter() - start)
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if message:
await self._send_message(message)
if isinstance(result, Exception):
self._bump_errors()
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self.REQUEST_ERRORS_COUNT.labels(
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method=request.method,
version=self.client_version
).inc()
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def connection_lost(self, exc):
# Cancel pending requests and message processing
self.connection.raise_pending_requests(exc)
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super().connection_lost(exc)
# External API
def default_connection(self):
"""Return a default connection if the user provides none."""
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return JSONRPCConnection(JSONRPCv2)
def default_framer(self):
"""Return a default framer."""
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return NewlineFramer()
async def handle_request(self, request):
pass
async def send_request(self, method, args=()):
"""Send an RPC request over the network."""
if self.is_closing():
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raise asyncio.TimeoutError("Trying to send request on a recently dropped connection.")
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message, event = self.connection.send_request(Request(method, args))
await self._send_message(message)
await event.wait()
result = event.result
if isinstance(result, Exception):
raise result
return result
async def send_notification(self, method, args=()) -> bool:
"""Send an RPC notification over the network."""
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message = self.connection.send_notification(Notification(method, args))
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self.NOTIFICATION_COUNT.labels(method=method, version=self.client_version).inc()
try:
await self._send_message(message)
return True
except asyncio.TimeoutError:
self.logger.info("timeout sending address notification to %s", self.peer_address_str(for_log=True))
self.abort()
return False
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def send_batch(self, raise_errors=False):
"""Return a BatchRequest. Intended to be used like so:
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async with session.send_batch() as batch:
batch.add_request("method1")
batch.add_request("sum", (x, y))
batch.add_notification("updated")
for result in batch.results:
...
Note that in some circumstances exceptions can be raised; see
BatchRequest doc string.
"""
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return BatchRequest(self, raise_errors)
class Server:
"""A simple wrapper around an asyncio.Server object."""
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def __init__(self, session_factory, host=None, port=None, *,
loop=None, **kwargs):
self.host = host
self.port = port
self.loop = loop or asyncio.get_event_loop()
self.server = None
self._session_factory = session_factory
self._kwargs = kwargs
async def listen(self):
self.server = await self.loop.create_server(
self._session_factory, self.host, self.port, **self._kwargs)
async def close(self):
"""Close the listening socket. This does not close any ServerSession
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objects created to handle incoming connections.
"""
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if self.server:
self.server.close()
await self.server.wait_closed()
self.server = None