tInitial ZeroMQ client implementation. - obelisk - Electrum server using libbitcoin as its backend
HTML git clone https://git.parazyd.org/obelisk
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---
DIR commit bae345a9b95dff3ae89ec354a12b6bab8182c7d6
DIR parent 3fa9d2257f2d75456b9479d22a39f633fda58858
HTML Author: parazyd <parazyd@dyne.org>
Date: Wed, 7 Apr 2021 16:46:53 +0200
Initial ZeroMQ client implementation.
Diffstat:
A electrumobelisk/zeromq.py | 246 +++++++++++++++++++++++++++++++
1 file changed, 246 insertions(+), 0 deletions(-)
---
DIR diff --git a/electrumobelisk/zeromq.py b/electrumobelisk/zeromq.py
t@@ -0,0 +1,246 @@
+#!/usr/bin/env python3
+# Copyright (C) 2020-2021 Ivan J. <parazyd@dyne.org>
+#
+# This file is part of obelisk
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License version 3
+# as published by the Free Software Foundation.
+#
+# 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+"""ZeroMQ implementation for libbitcoin"""
+import asyncio
+import struct
+from random import randint
+
+import zmq
+import zmq.asyncio
+
+from libbitcoin_errors import make_error_code, ErrorCode
+
+
+def create_random_id():
+ """Generate a random request ID"""
+ max_uint32 = 4294967295
+ return randint(0, max_uint32)
+
+
+class ClientSettings:
+ """Class implementing ZMQ client settings"""
+ def __init__(self, timeout=10, context=None, loop=None):
+ self._timeout = timeout
+ self._context = context
+ self._loop = loop
+
+ @property
+ def context(self):
+ """ZMQ context property"""
+ if not self.context:
+ ctx = zmq.asyncio.Context()
+ ctx.linger = 500 # in milliseconds
+ self._context = ctx
+ return self._context
+
+ @context.setter
+ def context(self, context):
+ self._context = context
+
+ @property
+ def timeout(self):
+ """Set to None for no timeout"""
+ return self._timeout
+
+ @timeout.setter
+ def timeout(self, timeout):
+ self._timeout = timeout
+
+
+class Request:
+ """Class implementing a _send_ request.
+ This is either a simple request/response affair or a subscription.
+ """
+ def __init__(self, socket, command, data):
+ self.id_ = create_random_id()
+ self.socket = socket
+ self.command = command
+ self.data = data
+ self.future = asyncio.Future()
+ self.queue = None
+
+ async def send(self):
+ """Send the ZMQ request"""
+ request = [self.command, struct.pack("<I", self.id_), self.data]
+ await self.socket.send_multipart(request)
+
+ def is_subscription(self):
+ """If the request is a subscription, then the response to this
+ request is a notification.
+ """
+ return self.queue is not None
+
+ def __str__(self):
+ return "Request(command, ID) {}, {:d}".format(self.command, self.id_)
+
+
+class InvalidServerResponseException(Exception):
+ """Exception for invalid server responses"""
+
+
+class Response:
+ """Class implementing a request response"""
+ def __init__(self, frame):
+ if len(frame) != 3:
+ raise InvalidServerResponseException(
+ f"Length of the frame was not 3: {len(frame)}")
+
+ self.command = frame[0]
+ self.request_id = struct.unpack("<I", frame[1])[0]
+ error_code = struct.unpack("<I", frame[2][:4])[0]
+ self.error_code = make_error_code(error_code)
+ self.data = frame[2][4:]
+
+ def is_bound_for_queue(self):
+ return len(self.data) > 0
+
+ def __str__(self):
+ return (
+ "Response(command, request ID, error code, data):" +
+ f" {self.command}, {self.request_id}, {self.error_code}, {self.data}"
+ )
+
+
+class RequestCollection:
+ """RequestCollection carries a list of Requests and matches incoming
+ responses to them.
+ """
+ def __init__(self, socket, loop):
+ self._socket = socket
+ self._requests = {}
+ self._task = asyncio.ensure_future(self._run(), loop=loop)
+
+ async def _run(self):
+ while True:
+ await self._receive()
+
+ async def stop(self):
+ """Stops listening for incoming responses (or subscription) messages.
+ Returns the number of _responses_ expected but which are now dropped
+ on the floor.
+ """
+ self._task.cancel()
+ try:
+ await self._task
+ except asyncio.CancelledError:
+ return len(self._requests)
+
+ async def _receive(self):
+ frame = await self._socket.recv_multipart()
+ response = Response(frame)
+
+ if response.request_id in self._requests:
+ self._handle_response(response)
+ else:
+ print(
+ f"DEBUG: RequestCollection unhandled response {response.command}:{response.request_id}"
+ )
+
+ def _handle_response(self, response):
+ request = self._requests[response.request_id]
+
+ if request.is_subscription():
+ if response.is_bound_for_queue():
+ # TODO: decode the data into something usable
+ request.queue.put_nowait(response.data)
+ else:
+ request.future.set_result(response)
+ else:
+ self.delete_request(request)
+ request.future.set_result(response)
+
+ def add_request(self, request):
+ # TODO: we should maybe check if the request.id_ is unique
+ self._requests[request.id_] = request
+
+ def delete_request(self, request):
+ del self._requests[request.id_]
+
+
+class Client:
+ """This class represents a connection to a libbitcoin server.
+ hostname -- the server DNS name to connect to
+ ports -- a dictionary containing four keys; query/heartbeat/block/tx
+ """
+
+ # def __init__(self, hostname, ports, settings=ClientSettings()):
+ def __init__(self, hostname, ports, loop):
+ self._hostname = hostname
+ self._ports = ports
+ # self._settings = settings
+ self._settings = ClientSettings(loop=loop)
+ self._query_socket = self._create_query_socket()
+ self._block_socket = self._create_block_socket()
+ self._request_collection = RequestCollection(self._query_socket,
+ self._settings._loop)
+
+ async def stop(self):
+ self._query_socket.close()
+ self._block_socket.close()
+ return await self._request_collection.stop()
+
+ def _create_block_socket(self):
+ socket = self._settings.context.socket(
+ zmq.SUB, # pylint: disable=E1101
+ io_loop=self._settings._loop, # pylint: disable=W0212
+ )
+ socket.connect(self.__server_url(self._hostname, self._ports["block"]))
+ socket.setsockopt_string(zmq.SUBSCRIBE, "") # pylint: disable=E1101
+ return socket
+
+ def _create_query_socket(self):
+ socket = self._settings.context.socket(
+ zmq.DEALER, # pylint: disable=E1101
+ io_loop=self._settings._loop, # pylint: disable=W0212
+ )
+ socket.connect(self.__server_url(self._hostname, self._ports["query"]))
+ return socket
+
+ async def _subscription_request(self, command, data):
+ request = await self._request(command, data)
+ request.queue = asyncio.Queue(loop=self._settings._loop) # pylint: disable=W0212
+ error_code, _ = await self._wait_for_response(request)
+ return error_code, request.queue
+
+ async def _simple_request(self, command, data):
+ return await self._wait_for_response(await
+ self._request(command, data))
+
+ async def _request(self, command, data):
+ """Make a generic request. Both options are byte objects specified
+ like b'blockchain.fetch_block_header' as an example.
+ """
+ request = Request(self._query_socket, command, data)
+ await request.send()
+ self._request_collection.add_request(request)
+ return request
+
+ async def _wait_for_response(self, request):
+ try:
+ response = await asyncio.wait_for(request.future,
+ self._settings.timeout)
+ except asyncio.TimeoutError:
+ self._request_collection.delete_request(request)
+ return ErrorCode.channel_timeout, None
+
+ assert response.command == request.command
+ assert response.request_id == request.id_
+ return response.error_code, response.data
+
+ @staticmethod
+ def __server_url(hostname, port):
+ return "tcp://" + hostname + ":" + str(port)