introduced StringIO
introduce line oriented communication + HasIodev Mixin + minor fixes Change-Id: I22605824d2f45147224840172bae281f85c80a11 Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21953 Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de> Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
This commit is contained in:
266
secop/stringio.py
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266
secop/stringio.py
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#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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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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# Markus Zolliker <markus.zolliker@psi.ch>
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# *****************************************************************************
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"""Line oriented stream communication
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implements TCP/IP and is be used as a base for SerialIO
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"""
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import time
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import socket
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import threading
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import re
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from secop.modules import Module, Communicator, Parameter, Command, Property, Attached
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from secop.datatypes import StringType, FloatRange, ArrayOf, BoolType, TupleOf
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from secop.errors import CommunicationFailedError, CommunicationSilentError
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from secop.poller import REGULAR
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from secop.metaclass import Done
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class StringIO(Communicator):
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"""line oriented communicator
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implementation for TCP/IP streams.
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other types have to override the following methods:
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createConnection, readWithTimeout, writeBytes, closeConnection
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self healing is assured by polling the parameter 'is_connected'
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"""
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properties = {
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'uri':
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Property('hostname:portnumber', datatype=StringType()),
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'end_of_line':
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Property('end_of_line character', datatype=StringType(),
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default='\n', settable=True),
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'encoding':
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Property('used encoding', datatype=StringType(),
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default='ascii', settable=True),
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'identification':
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Property('a list of tuples with commands and expected responses as regexp',
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datatype=ArrayOf(TupleOf(StringType(),StringType())), default=[], export=False),
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}
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parameters = {
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'timeout':
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Parameter('timeout', datatype=FloatRange(0), default=1),
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'wait_before':
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Parameter('wait time before sending', datatype=FloatRange(), default=0),
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'is_connected':
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Parameter('connection state', datatype=BoolType(), readonly=False, poll=REGULAR),
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'pollinterval':
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Parameter('reconnect interval', datatype=FloatRange(0), readonly=False, default=10),
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}
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commands = {
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'multicomm':
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Command('execute multiple commands in one go',
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argument=ArrayOf(StringType()), result= ArrayOf(StringType()))
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}
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def earlyInit(self):
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self._stream = None
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self._lock = threading.RLock()
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self._end_of_line = self.end_of_line.encode(self.encoding)
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self._connect_error = None
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self._last_error = 'not connected'
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def createConnection(self):
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"""create connection
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in case of success, self.is_connected MUST be set to True by implementors
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"""
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uri = self.uri
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if uri.startswith('tcp://'):
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uri = uri[6:]
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try:
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host, port = uri.split(':')
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self._stream = socket.create_connection((host, int(port)), 10)
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self.is_connected = True
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except (ConnectionRefusedError, socket.gaierror) as e:
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raise CommunicationFailedError(str(e))
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except Exception as e:
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# this is really bad, do not try again
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self._connect_error = e
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raise
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def readWithTimeout(self, timeout):
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"""read with timeout
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Read bytes available now, or wait at most the specified timeout until some bytes
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are available. Throw an error, if disconnected.
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If no bytes are available, return b''
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to be overwritten for other stream types
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"""
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if timeout is None or timeout < 0:
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raise ValueError('illegal timeout %r' % timeout)
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if not self.is_connected:
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raise CommunicationSilentError(self._last_error)
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self._stream.settimeout(timeout)
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try:
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reply = self._stream.recv(4096)
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if reply:
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return reply
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except (BlockingIOError, socket.timeout):
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return b''
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except Exception as e:
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self.closeConnection()
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raise CommunicationFailedError('disconnected because of %s' % e)
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# other end disconnected
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self.closeConnection()
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raise CommunicationFailedError('other end disconnected')
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def writeBytes(self, data):
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"""write bytes
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to be overwritten for other stream types
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"""
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self._stream.sendall(data)
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def closeConnection(self):
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"""close connection
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self.is_connected MUST be set to False by implementors
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"""
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if not self._stream:
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return
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self.log.debug('disconnect %s' % self.uri)
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try:
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self._stream.shutdown(socket.SHUT_RDWR)
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except socket.error:
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pass
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try:
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self._stream.close()
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except socket.error:
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pass
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self._stream = None
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self.is_connected = False
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def read_is_connected(self):
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"""try to reconnect, when not connected
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self.is_connected is changed only by self.connectStart or self.closeConnection
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"""
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if self.is_connected:
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return Done # no need for intermediate updates
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try:
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self.connectStart()
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if self._last_error:
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self.log.info('connected')
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self._last_error = 'connected'
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return Done
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except Exception as e:
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if str(e) == self._last_error:
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raise CommunicationSilentError(str(e))
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self._last_error = str(e)
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self.log.error(self._last_error)
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raise
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return Done
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def write_is_connected(self, value):
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"""value = True: connect if not yet done
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value = False: disconnect (will be reconnected automatically)
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"""
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if not value:
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self.closeConnection()
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return False
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return self.read_is_connected()
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def connectStart(self):
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if not self.is_connected:
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self.createConnection()
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for command, regexp in self.identification:
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reply = self.do_communicate(command)
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if not re.match(regexp, reply):
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self.closeConnection()
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raise CommunicationFailedError('bad response: %s does not match %s' %
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(reply, regexp))
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def do_communicate(self, command):
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'''send a command and receive a reply
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using end_of_line, encoding and self._lock
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for commands without reply, join it with a query command,
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wait_before is respected for end_of_lines within a command.
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'''
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if not self.is_connected:
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self.read_is_connected() # try to reconnect
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try:
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with self._lock:
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# read garbage and wait before send
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if self.wait_before:
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cmds = command.split(self.end_of_line)
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else:
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cmds = [command]
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garbage = None
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for cmd in cmds:
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if self.wait_before:
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time.sleep(self.wait_before)
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if garbage is None: # read garbage only once
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garbage = ''
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data = self.readWithTimeout(0)
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while data:
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garbage += data
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data = self.readWithTimeout(0)
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if garbage:
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self.log.debug('garbage: %s', garbage.decode(self.encoding))
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self.writeBytes((cmd + self.end_of_line).encode(self.encoding))
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timeout = self.timeout
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buffer = b''
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data = True
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while data:
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data = self.readWithTimeout(timeout)
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buffer += data
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if self._end_of_line in buffer:
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break
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else:
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raise CommunicationFailedError('timeout')
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reply = buffer.split(self._end_of_line, 1)[0].decode(self.encoding)
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self.log.debug('recv: %s', reply)
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return reply
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except Exception as e:
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if str(e) == self._last_error:
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raise CommunicationSilentError(str(e))
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self._last_error = str(e)
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self.log.error(self._last_error)
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raise
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def do_multicomm(self, commands):
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replies = []
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with self._lock:
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for cmd in commands:
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replies.append(self.do_communicate(cmd))
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return replies
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class HasIodev(Module):
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"""Mixin for modules using a communicator"""
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properties = {
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'iodev': Attached(),
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}
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def initModule(self):
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try:
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self._iodev.read_is_connected()
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except CommunicationFailedError:
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pass
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super().initModule()
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def sendRecv(self, command):
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return self._iodev.do_communicate(command)
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