Markus Zolliker
9825b9c135
new client intended as base class for all clients - based on Ennos secop client in nicos ([WIP] provide secop client) - self healing connection singletons - extension for other than TCP is foreseen (by extending new uri schemes) - extensible name mangling - seperate rx and tx threads supporting events - internal cache - extensible error handling - callback for unhandled messages - callback for descriptive data change - callback for node stat change (connected, disconnected) - a short close down and reconnect without change in descriptive data does not disturb the client side works with secop-gui (change follows), planned to be used for Frappy internal secop proxy and as a replacement for secop.client.baseclient.Client in the nicos secop device. -> secop/client/baseclient.py to be removed after planned changes moved secop/client/__init__.py to secop/client/console.py because secop.client would be the natural place to put the new base class. Change-Id: I1a7b1f1ded2221a8f9fcdd52f9cc7414e8fbe035 Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/22218 Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de> Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
141 lines
4.1 KiB
Python
141 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
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# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
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# Markus Zolliker <markus.zolliker@psi.ch>
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#
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# *****************************************************************************
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"""asynchonous connections
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generic class for byte oriented communication
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includes implementation for TCP connections
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"""
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import socket
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import time
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from secop.lib import parseHostPort, tcpSocket, closeSocket
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class ConnectionClosed(ConnectionError):
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pass
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class AsynConn:
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timeout = 1 # inter byte timeout
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SCHEME_MAP = {}
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connection = None # is not None, if connected
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defaultport = None
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def __new__(cls, uri):
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scheme = uri.split('://')[0]
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iocls = cls.SCHEME_MAP.get(scheme, None)
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if not iocls:
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# try tcp, if scheme not given
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try:
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host_port = parseHostPort(uri, cls.defaultport)
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except (ValueError, TypeError, AssertionError):
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raise ValueError('invalid uri: %s' % uri)
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iocls = cls.SCHEME_MAP['tcp']
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uri = 'tcp://%s:%d' % host_port
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return object.__new__(iocls)
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def __init__(self, *args):
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self._rxbuffer = b''
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def __del__(self):
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self.disconnect()
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@classmethod
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def register_scheme(cls, scheme):
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cls.SCHEME_MAP[scheme] = cls
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def disconnect(self):
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raise NotImplementedError
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def send(self, data):
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"""send data (bytes!)
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tries to send all data"""
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raise NotImplementedError
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def recv(self):
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"""return bytes received within timeout
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in contrast to socket.recv:
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- returns b'' on timeout
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- raises ConnectionClosed if the other end has disconnected
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"""
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raise NotImplementedError
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def readline(self, timeout=None):
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"""read one line
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return either a complete line or None in case of timeout
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the timeout argument may increase, but not decrease the default timeout
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"""
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if timeout:
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end = time.time() + timeout
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while b'\n' not in self._rxbuffer:
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data = self.recv()
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if not data:
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if timeout:
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if time.time() < end:
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continue
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raise TimeoutError('timeout in readline')
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return None
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self._rxbuffer += data
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line, self._rxbuffer = self._rxbuffer.split(b'\n', 1)
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return line
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def writeline(self, line):
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self.send(line + b'\n')
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class AsynTcp(AsynConn):
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def __init__(self, uri):
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super().__init__()
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self.uri = uri
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if uri.startswith('tcp://'):
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# should be the case always
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uri = uri[6:]
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self.connection = tcpSocket(uri, self.defaultport, self.timeout)
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def disconnect(self):
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if self.connection:
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closeSocket(self.connection)
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self.connection = None
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def send(self, data):
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"""send data (bytes!)"""
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self.connection.sendall(data)
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def recv(self):
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"""return bytes received within 1 sec"""
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try:
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data = self.connection.recv(8192)
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if data:
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return data
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except socket.timeout:
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# timeout while waiting
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return b''
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raise ConnectionClosed() # marks end of connection
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AsynTcp.register_scheme('tcp')
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