forked from LBRYCommunity/lbry-sdk
550 lines
20 KiB
Python
550 lines
20 KiB
Python
# Copyright (c) 2018, Neil Booth
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#
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# All rights reserved.
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#
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# The MIT License (MIT)
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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__all__ = ('Connector', 'RPCSession', 'MessageSession', 'Server',
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'BatchError')
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import asyncio
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from asyncio import Event, CancelledError
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import logging
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import time
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from contextlib import suppress
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from prometheus_client import Counter, Histogram
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from lbry.wallet.tasks import TaskGroup
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from .jsonrpc import Request, JSONRPCConnection, JSONRPCv2, JSONRPC, Batch, Notification
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from .jsonrpc import RPCError, ProtocolError
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from .framing import BadMagicError, BadChecksumError, OversizedPayloadError, BitcoinFramer, NewlineFramer
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HISTOGRAM_BUCKETS = (
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.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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)
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class Connector:
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def __init__(self, session_factory, host=None, port=None, proxy=None,
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**kwargs):
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self.session_factory = session_factory
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self.host = host
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self.port = port
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self.proxy = proxy
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self.loop = kwargs.get('loop', asyncio.get_event_loop())
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self.kwargs = kwargs
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async def create_connection(self):
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"""Initiate a connection."""
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connector = self.proxy or self.loop
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return await connector.create_connection(
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self.session_factory, self.host, self.port, **self.kwargs)
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async def __aenter__(self):
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transport, self.protocol = await self.create_connection()
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return self.protocol
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async def __aexit__(self, exc_type, exc_value, traceback):
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await self.protocol.close()
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class SessionBase(asyncio.Protocol):
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"""Base class of networking sessions.
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There is no client / server distinction other than who initiated
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the connection.
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To initiate a connection to a remote server pass host, port and
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proxy to the constructor, and then call create_connection(). Each
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successful call should have a corresponding call to close().
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Alternatively if used in a with statement, the connection is made
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on entry to the block, and closed on exit from the block.
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"""
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max_errors = 10
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def __init__(self, *, framer=None, loop=None):
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self.framer = framer or self.default_framer()
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self.loop = loop or asyncio.get_event_loop()
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self.logger = logging.getLogger(self.__class__.__name__)
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self.transport = None
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# Set when a connection is made
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self._address = None
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self._proxy_address = None
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# For logger.debug messages
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self.verbosity = 0
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# Cleared when the send socket is full
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self._can_send = Event()
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self._can_send.set()
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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
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self.max_send_delay = 60
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# 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
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self.send_count = 0
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self.send_size = 0
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self.last_send = self.start_time
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self.recv_count = 0
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self.recv_size = 0
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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):
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try:
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await asyncio.wait_for(self._can_send.wait(), secs)
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except asyncio.TimeoutError:
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self.abort()
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raise asyncio.TimeoutError(f'task timed out after {secs}s')
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async def _send_message(self, message):
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if not self._can_send.is_set():
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await self._limited_wait(self.max_send_delay)
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if not self.is_closing():
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framed_message = self.framer.frame(message)
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self.send_size += len(framed_message)
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self.send_count += 1
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self.last_send = time.perf_counter()
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if self.verbosity >= 4:
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self.logger.debug(f'Sending framed message {framed_message}')
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self.transport.write(framed_message)
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def _bump_errors(self):
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self.errors += 1
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if self.errors >= self.max_errors:
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# Don't await self.close() because that is self-cancelling
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self._close()
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def _close(self):
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if self.transport:
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self.transport.close()
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# asyncio framework
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def data_received(self, framed_message):
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"""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:
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self.logger.debug(f'Received framed message {framed_message}')
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self.recv_size += len(framed_message)
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self.framer.received_bytes(framed_message)
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def pause_writing(self):
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"""Transport calls when the send buffer is full."""
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if not self.is_closing():
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self._can_send.clear()
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self.transport.pause_reading()
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def resume_writing(self):
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"""Transport calls when the send buffer has room."""
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if not self._can_send.is_set():
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self._can_send.set()
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self.transport.resume_reading()
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def connection_made(self, transport):
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"""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
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# This would throw if called on a closed SSL transport. Fixed
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# in asyncio in Python 3.6.1 and 3.5.4
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peer_address = transport.get_extra_info('peername')
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# If the Socks proxy was used then _address is already set to
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# the remote address
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if self._address:
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self._proxy_address = peer_address
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else:
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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):
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"""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
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self.transport = None
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self._task_group.cancel()
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if self._pm_task:
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self._pm_task.cancel()
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# Release waiting tasks
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self._can_send.set()
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# External API
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def default_framer(self):
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"""Return a default framer."""
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raise NotImplementedError
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def peer_address(self):
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"""Returns the peer's address (Python networking address), or None if
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no connection or an error.
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This is the result of socket.getpeername() when the connection
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was made.
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"""
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return self._address
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def peer_address_str(self, for_log=True):
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"""Returns the peer's IP address and port as a human-readable
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string."""
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if not self._address:
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return 'unknown'
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ip_addr_str, port = self._address[:2]
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if ':' in ip_addr_str:
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return f'[{ip_addr_str}]:{port}'
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else:
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return f'{ip_addr_str}:{port}'
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def is_closing(self):
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"""Return True if the connection is closing."""
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return not self.transport or self.transport.is_closing()
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def abort(self):
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"""Forcefully close the connection."""
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if self.transport:
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self.transport.abort()
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# TODO: replace with synchronous_close
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async def close(self, *, force_after=30):
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"""Close the connection and return when closed."""
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self._close()
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if self._pm_task:
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with suppress(CancelledError):
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await asyncio.wait([self._pm_task], timeout=force_after)
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self.abort()
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await self._pm_task
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def synchronous_close(self):
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self._close()
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if self._pm_task and not self._pm_task.done():
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self._pm_task.cancel()
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class MessageSession(SessionBase):
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"""Session class for protocols where messages are not tied to responses,
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such as the Bitcoin protocol.
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To use as a client (connection-opening) session, pass host, port
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and perhaps a proxy.
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"""
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async def _receive_messages(self):
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while not self.is_closing():
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try:
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message = await self.framer.receive_message()
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except BadMagicError as e:
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magic, expected = e.args
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self.logger.error(
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f'bad network magic: got {magic} expected {expected}, '
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f'disconnecting'
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)
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self._close()
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except OversizedPayloadError as e:
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command, payload_len = e.args
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self.logger.error(
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f'oversized payload of {payload_len:,d} bytes to command '
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f'{command}, disconnecting'
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)
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self._close()
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except BadChecksumError as e:
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payload_checksum, claimed_checksum = e.args
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self.logger.warning(
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f'checksum mismatch: actual {payload_checksum.hex()} '
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f'vs claimed {claimed_checksum.hex()}'
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)
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self._bump_errors()
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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):
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try:
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await self.handle_message(message)
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except ProtocolError as e:
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self.logger.error(f'{e}')
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self._bump_errors()
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except CancelledError:
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raise
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except Exception:
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self.logger.exception(f'exception handling {message}')
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self._bump_errors()
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# External API
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def default_framer(self):
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"""Return a bitcoin framer."""
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return BitcoinFramer(bytes.fromhex('e3e1f3e8'), 128_000_000)
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async def handle_message(self, message):
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"""message is a (command, payload) pair."""
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pass
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async def send_message(self, message):
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"""Send a message (command, payload) over the network."""
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await self._send_message(message)
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class BatchError(Exception):
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def __init__(self, request):
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self.request = request # BatchRequest object
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class BatchRequest:
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"""Used to build a batch request to send to the server. Stores
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the
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Attributes batch and results are initially None.
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Adding an invalid request or notification immediately raises a
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ProtocolError.
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On exiting the with clause, it will:
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1) create a Batch object for the requests in the order they were
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added. If the batch is empty this raises a ProtocolError.
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2) set the "batch" attribute to be that batch
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3) send the batch request and wait for a response
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4) raise a ProtocolError if the protocol was violated by the
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server. Currently this only happens if it gave more than one
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response to any request
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5) otherwise there is precisely one response to each Request. Set
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the "results" attribute to the tuple of results; the responses
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are ordered to match the Requests in the batch. Notifications
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do not get a response.
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6) if raise_errors is True and any individual response was a JSON
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RPC error response, or violated the protocol in some way, a
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BatchError exception is raised. Otherwise the caller can be
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certain each request returned a standard result.
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"""
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def __init__(self, session, raise_errors):
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self._session = session
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self._raise_errors = raise_errors
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self._requests = []
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self.batch = None
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self.results = None
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def add_request(self, method, args=()):
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self._requests.append(Request(method, args))
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def add_notification(self, method, args=()):
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self._requests.append(Notification(method, args))
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def __len__(self):
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return len(self._requests)
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async def __aenter__(self):
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return self
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async def __aexit__(self, exc_type, exc_value, traceback):
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if exc_type is None:
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self.batch = Batch(self._requests)
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message, event = self._session.connection.send_batch(self.batch)
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await self._session._send_message(message)
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await event.wait()
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self.results = event.result
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if self._raise_errors:
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if any(isinstance(item, Exception) for item in event.result):
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raise BatchError(self)
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NAMESPACE = "wallet_server"
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class RPCSession(SessionBase):
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"""Base class for protocols where a message can lead to a response,
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for example JSON RPC."""
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RESPONSE_TIMES = Histogram("response_time", "Response times", namespace=NAMESPACE,
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labelnames=("method", "version"), buckets=HISTOGRAM_BUCKETS)
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NOTIFICATION_COUNT = Counter("notification", "Number of notifications sent (for subscriptions)",
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namespace=NAMESPACE, labelnames=("method", "version"))
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REQUEST_ERRORS_COUNT = Counter(
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"request_error", "Number of requests that returned errors", namespace=NAMESPACE,
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labelnames=("method", "version")
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)
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RESET_CONNECTIONS = Counter(
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"reset_clients", "Number of reset connections by client version",
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namespace=NAMESPACE, labelnames=("version",)
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)
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def __init__(self, *, framer=None, loop=None, connection=None):
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super().__init__(framer=framer, loop=loop)
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self.connection = connection or self.default_connection()
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self.client_version = 'unknown'
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async def _receive_messages(self):
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while not self.is_closing():
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try:
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message = await self.framer.receive_message()
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except MemoryError:
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self.logger.warning('received oversized message from %s:%s, dropping connection',
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self._address[0], self._address[1])
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self.RESET_CONNECTIONS.labels(version=self.client_version).inc()
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self._close()
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return
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self.last_recv = time.perf_counter()
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self.recv_count += 1
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try:
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requests = self.connection.receive_message(message)
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except ProtocolError as e:
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self.logger.debug(f'{e}')
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if e.error_message:
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await self._send_message(e.error_message)
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if e.code == JSONRPC.PARSE_ERROR:
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self.max_errors = 0
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self._bump_errors()
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else:
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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):
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start = time.perf_counter()
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try:
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result = await self.handle_request(request)
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except (ProtocolError, RPCError) as e:
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result = e
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except CancelledError:
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raise
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except Exception:
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reqstr = str(request)
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self.logger.exception(f'exception handling {reqstr[:16_000]}')
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result = RPCError(JSONRPC.INTERNAL_ERROR,
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'internal server error')
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if isinstance(request, Request):
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message = request.send_result(result)
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self.RESPONSE_TIMES.labels(
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method=request.method,
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version=self.client_version
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).observe(time.perf_counter() - start)
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if message:
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await self._send_message(message)
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if isinstance(result, Exception):
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self._bump_errors()
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self.REQUEST_ERRORS_COUNT.labels(
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method=request.method,
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version=self.client_version
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).inc()
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def connection_lost(self, exc):
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# Cancel pending requests and message processing
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self.connection.raise_pending_requests(exc)
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super().connection_lost(exc)
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# External API
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def default_connection(self):
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"""Return a default connection if the user provides none."""
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return JSONRPCConnection(JSONRPCv2)
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def default_framer(self):
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"""Return a default framer."""
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return NewlineFramer()
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async def handle_request(self, request):
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pass
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async def send_request(self, method, args=()):
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"""Send an RPC request over the network."""
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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))
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await self._send_message(message)
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await event.wait()
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result = event.result
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if isinstance(result, Exception):
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raise result
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return result
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async def send_notification(self, method, args=()) -> bool:
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"""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()
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try:
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await self._send_message(message)
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return True
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except asyncio.TimeoutError:
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self.logger.info("timeout sending address notification to %s", self.peer_address_str(for_log=True))
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self.abort()
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return False
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async def send_notifications(self, notifications) -> bool:
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"""Send an RPC notification over the network."""
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message, _ = self.connection.send_batch(notifications)
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try:
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await self._send_message(message)
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return True
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except asyncio.TimeoutError:
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self.logger.info("timeout sending address notification to %s", self.peer_address_str(for_log=True))
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self.abort()
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return False
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def send_batch(self, raise_errors=False):
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"""Return a BatchRequest. Intended to be used like so:
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async with session.send_batch() as batch:
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batch.add_request("method1")
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batch.add_request("sum", (x, y))
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batch.add_notification("updated")
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for result in batch.results:
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...
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Note that in some circumstances exceptions can be raised; see
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BatchRequest doc string.
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"""
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return BatchRequest(self, raise_errors)
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class Server:
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"""A simple wrapper around an asyncio.Server object."""
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def __init__(self, session_factory, host=None, port=None, *,
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loop=None, **kwargs):
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self.host = host
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self.port = port
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self.loop = loop or asyncio.get_event_loop()
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self.server = None
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self._session_factory = session_factory
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self._kwargs = kwargs
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async def listen(self):
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self.server = await self.loop.create_server(
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self._session_factory, self.host, self.port, **self._kwargs)
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async def close(self):
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"""Close the listening socket. This does not close any ServerSession
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objects created to handle incoming connections.
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"""
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if self.server:
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self.server.close()
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await self.server.wait_closed()
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self.server = None
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