beremiz

Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

2018-08-10, Andrey Skvortsov
a3ac46366b86
Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

traceback:
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 1433, in OnPouSelectedChanged
window.RefreshView()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 837, in RefreshView
self.RefreshProcessVariables()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 886, in RefreshProcessVariables
slaves = self.Controler.GetSlaves(**self.CurrentNodesFilter)
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/EthercatMaster.py", line 341, in GetSlaves
for slave in self.Config.getConfig().getSlave():
:_'lxml.etree._Element'_object_has_no_attribute_'getSlave'

Steps to reproduce problem:

- Add new EtherCAT master
- Add new EthercatNode to the master
- double click on


this is looks like dirty hack to fix strange problem with initial[0]
changing its type after returning from _init_ method to lxml.etree._Element
As a result all methods generated by class factory are lost.

For example, in function initMethod initial[0].__class__ points to
xmlclass.xmlclass.Config. After map(self.append, initial)
self.Config.__class__ is 'xmlclass.xmlclass.Config' as well.
But after returning from initMethod (_init) in CreateElement
self.Config.__class__ has changed to lxml.etree._Element.


I've noticed similar behavior if copy/deepcopy is used for any child
of etree.ElementBase. See simple example below.
[-------------------------------------------------------------]
#!/usr/bin/python

from __future__ import print_function
from lxml import etree
import copy

class DefaultElementClass(etree.ElementBase):
def getLocalTag(self):
return etree.QName(self.tag).localname


def printInformation(x):
print(x, x.__class__, "getLocalTag" in dir(x))


a = DefaultElementClass()
printInformation(a)

#
printInformation(copy.copy(a))
printInformation(copy.deepcopy(a))
[-------------------------------------------------------------]
import os,subprocess,sys,ctypes
from threading import Thread
import ctypes,time,re
from targets.typemapping import LogLevelsDict
SDOAnswered = PLCBinary.SDOAnswered
SDOAnswered.restype = None
SDOAnswered.argtypes = []
SDOThread = None
SDOProc = None
Result = None
def SDOThreadProc(*params):
global Result, SDOProc
if params[0] == "upload":
cmdfmt = "ethercat upload -p %d -t %s 0x%.4x 0x%.2x"
else:
cmdfmt = "ethercat download -p %d -t %s 0x%.4x 0x%.2x %s"
command = cmdfmt % params[1:]
SDOProc = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)
res = SDOProc.wait()
output = SDOProc.communicate()[0]
if params[0] == "upload":
Result = None
if res == 0:
if params[2] in ["float", "double"]:
Result = float(output)
elif params[2] in ["string", "octet_string", "unicode_string"]:
Result = output
else:
hex_value, dec_value = output.split()
if int(hex_value, 16) == int(dec_value):
Result = int(dec_value)
else:
Result = res == 0
SDOAnswered()
if res != 0 :
PLCObject.LogMessage(
LogLevelsDict["WARNING"],
"%s : %s"%(command,output))
def EthercatSDOUpload(pos, index, subindex, var_type):
global SDOThread
SDOThread = Thread(target=SDOThreadProc, args=["upload", pos, var_type, index, subindex])
SDOThread.start()
def EthercatSDODownload(pos, index, subindex, var_type, value):
global SDOThread
SDOThread = Thread(target=SDOThreadProc, args=["download", pos, var_type, index, subindex, value])
SDOThread.start()
def GetResult():
global Result
return Result
KMSGPollThread=None
StopKMSGThread=False
def KMSGPollThreadProc():
"""
Logs Kernel messages starting with EtherCAT
Uses GLibc wrapper to Linux syscall "klogctl"
Last 4 KB are polled, and lines compared to last
captured line to detect new lines
"""
global StopKMSGThread
libc=ctypes.CDLL("libc.so.6")
klog = libc.klogctl
klog.argtypes = [ctypes.c_int, ctypes.c_char_p, ctypes.c_int]
klog.restype = ctypes.c_int
s=ctypes.create_string_buffer(4*1024)
last = None
while not StopKMSGThread:
l = klog(3,s,len(s)-1)
log = s.value[:l-1]
if last :
log = log.rpartition(last)[2]
if log :
last = log.rpartition('\n')[2]
for lvl,msg in re.findall(
r'<(\d)>\[\s*\d*\.\d*\]\s*(EtherCAT\s*.*)$',
log, re.MULTILINE):
PLCObject.LogMessage(
LogLevelsDict[{
"4":"WARNING",
"3":"CRITICAL"}.get(lvl,"DEBUG")],
msg)
time.sleep(0.5)
def _runtime_etherlab_init():
global KMSGPollThread, StopKMSGThread
StopKMSGThread = False
KMSGPollThread = Thread(target = KMSGPollThreadProc)
KMSGPollThread.start()
def _runtime_etherlab_cleanup():
global KMSGPollThread, StopKMSGThread, SDOProc, SDOThread
try:
os.kill(SDOProc.pid, SIGTERM)
except:
pass
SDOThread = None
StopKMSGThread = True
KMSGPollThread = None