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19
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1 "The basic infrastructure for maintaining a vxi-11 protocol connection to a remote device"
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2 _rcsid="$Id: vxi_11.py 323 2011-04-06 19:10:03Z marcus $"
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3
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4 import rpc
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5 from rpc import TCPClient, RawTCPClient
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6 import exceptions
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7 import struct
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8 import traceback
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9 import time
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10 import weakref
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11 import sys
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12 import select
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13
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14 #try:
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15 # import threading
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16 # threads=1
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17 #except:
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18 # threads=0
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19 threads=False
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20
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21 connection_dict={}
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22
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23 def close_all_connections():
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24 "disconnect and close out all vxi_11 connections created here, even if their object references have been lost"
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56
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25 for wobj in list(connection_dict.keys()):
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19
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26 name, wconn=connection_dict[wobj]
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27 conn=wconn() #dereference weak ref
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28 if conn is not None:
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29 try:
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30 conn.disconnect()
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31 except:
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32 conn.log_exception("***vxi_11.close_all_connections exception: ")
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33
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34 else:
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35 del connection_dict[wobj] #how did this happen?
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36
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37 class Junk_OneWayAbortClient(RawTCPClient):
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38 """OneWayAbortClient allows one to handle the strange, one-way abort rpc from an Agilent E5810.
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39 Really, it doesn't even do a one-way transmission... it loses aborts, so this is history """
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40
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41 def do_call(self):
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42 call = self.packer.get_buf()
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43 rpc.sendrecord(self.sock, call)
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44 self.unpacker.reset('\0\0\0\0') #put a valid return value into the unpacker
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45
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46 class VXI_11_Error(IOError):
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47 vxi_11_errors={
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48 0:"No error", 1:"Syntax error", 3:"Device not accessible",
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49 4:"Invalid link identifier", 5:"Parameter error", 6:"Channel not established",
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50 8:"Operation not supported", 9:"Out of resources", 11:"Device locked by another link",
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51 12:"No lock held by this link", 15:"IO Timeout", 17:"IO Error", 21:"Invalid Address",
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52 23:"Abort", 29:"Channel already established" ,
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53 "eof": "Cut off packet received in rpc.recvfrag()",
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54 "sync":"stream sync lost",
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55 "notconnected": "Device not connected"}
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56
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57 def identify_vxi_11_error(self, error):
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56
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58 if error in self.vxi_11_errors:
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59 return repr(error)+": "+self.vxi_11_errors[error]
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19
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60 else:
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56
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61 return repr(error)+": Unknown error code"
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19
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62
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63
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64 def __init__(self, code, **other_info):
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65 IOError.__init__(self, self.identify_vxi_11_error(code))
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66 self.code=code
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67 self.other_info=other_info
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68
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69 def __repr__(self):
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70 if self.other_info:
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71 return str(self)+": "+str(self.other_info)
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72 else:
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73 return str(self)
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74
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75 class VXI_11_Device_Not_Connected(VXI_11_Error):
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76 def __init__(self):
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77 VXI_11_Error.__init__(self,'notconnected')
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78
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79 class VXI_11_Device_Not_Locked(VXI_11_Error):
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80 pass
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81
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82 class VXI_11_Transient_Error(VXI_11_Error): #exceptions having to do with multiple use which might get better
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83 pass
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84
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85 class VXI_11_Timeout(VXI_11_Transient_Error):
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86 pass
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87
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88 class VXI_11_Locked_Elsewhere(VXI_11_Transient_Error):
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89 pass
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90
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91 class VXI_11_Stream_Sync_Lost(VXI_11_Transient_Error):
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92 def __init__(self, code, bytes):
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93 VXI_11_Transient_Error.__init__(self, code)
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94 self.other_info="bytes vacuumed = %d" % bytes
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95
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96
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97 class VXI_11_RPC_EOF(VXI_11_Transient_Error):
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98 pass
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99
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100 _VXI_11_enumerated_exceptions={ #common, correctable exceptions
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101 15:VXI_11_Timeout,
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102 11:VXI_11_Locked_Elsewhere,
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103 12:VXI_11_Device_Not_Locked
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104 }
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105
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106 class vxi_11_connection:
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107 """vxi_11_connection implements handling of devices compliant with vxi11.1-vxi11.3 protocols, with which
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108 the user should have some familiarity"""
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109
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110 debug_info=0
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111 debug_error=1
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112 debug_warning=2
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113 debug_all=3
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114
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115 debug_level=debug_info
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116
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117 OneWayAbort=0 #by default, this class uses two-way aborts, per official vxi-11 standard
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118
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119 def _list_packer(self, args):
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120 l=map(None, self.pack_type_list, args) # combine lists
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121 for packer, data in l:
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122 #print "packing " + str(data) + " with " + str(packer)
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123 packer(data)
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124
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125 def _list_unpacker(self):
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126 res = []
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127 for f in self.unpack_type_list:
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128 a = f()
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129 #print "Unpacked " + str(a) + " with " + str(f)
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130 res.append(a)
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131 return res
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132 #return [func() for func in self.unpack_type_list]
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133
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134 def _link_xdr_defs(self, channel):
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135 "self.link_xdr_defs() creates dictionaries of functions for packing and unpacking the various data types"
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136 p=channel.packer
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137 u=channel.unpacker
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138
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139 xdr_packer_defs={
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140 "write": (p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_opaque),
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141 "read": (p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_int, p.pack_int),
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142 "create_link": (p.pack_int, p.pack_bool, p.pack_uint, p.pack_string),
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143 "generic": (p.pack_int, p.pack_int, p.pack_int, p.pack_int),
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144 "lock": (p.pack_int, p.pack_int, p.pack_int),
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145 "id": (p.pack_int,)
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146 }
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147
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148 xdr_unpacker_defs={
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149 "write": (u.unpack_int, u.unpack_int),
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150 "read": (u.unpack_int, u.unpack_int, u.unpack_opaque),
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151 # *something* is transforming pack_int to pack_uint which (obviously) doesn't like getting negative numbers
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152 # Since LID is basically opaque unpack it as a uint to paper over the vileness
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153 "create_link": (u.unpack_uint, u.unpack_int, u.unpack_uint, u.unpack_uint),
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154 "read_stb":(u.unpack_int, u.unpack_int),
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155 "error": (u.unpack_int,)
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156 }
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157
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158 return xdr_packer_defs, xdr_unpacker_defs
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159
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160 def _setup_core_packing(self, pack, unpack):
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161 #print "setting up packing with " + pack
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162 self.pack_type_list, self.unpack_type_list=self._core_packers[pack],self._core_unpackers[unpack]
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163 #print "pack_type_list now " + str(self.pack_type_list)
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164 #print "unpack_type_list now " + str(self.unpack_type_list)
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165
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166 def post_init(self):
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167 pass
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168
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169 def simple_log_error(self, message, level=debug_error, file=None):
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170 if level <= self.debug_level:
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171 if file is None:
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172 file=sys.stderr
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56
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173 print(self.device_name, message, file=file)
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19
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174
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175 def fancy_log_error(self, message, level=debug_error, file=None):
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176 if level <= self.debug_level:
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177 message=str(message).strip()
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178 level_str=("**INFO*****", "**ERROR****", "**WARNING**", "**DEBUG****")[level]
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179 if file is None:
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180 file=sys.stderr
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56
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181 print(time.asctime().strip(), '\t', level_str, '\t', self.shortname, '\t', \
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182 message.replace('\n','\n\t** ').replace('\r','\n\t** '), file=file)
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19
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183
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184 def log_error(self, message, level=debug_error, file=None):
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185 "override log_error() for sending messages to special places or formatting differently"
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186 self.fancy_log_error(message, level, file)
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187
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188 def log_traceback(self, main_message='', file=None):
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189 exlist=traceback.format_exception(*sys.exc_info())
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190 s=main_message+'\n'
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191 for i in exlist:
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192 s=s+i
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193
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194 self.log_error(s, self.debug_error, file)
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195
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196 def log_info(self, message, file=None):
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197 self.log_error(message, self.debug_info, file)
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198
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199 def log_warning(self, message, file=None):
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200 self.log_error(message, self.debug_warning, file)
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201
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202 def log_debug(self, message, file=None):
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203 self.log_error(message, self.debug_all, file)
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204
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205 def log_exception(self, main_message='', file=None):
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206 self.log_error(main_message+traceback.format_exception_only(*(sys.exc_info()[:2]))[0], self.debug_error, file)
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207
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208 def __init__(self, host='127.0.0.1', device="inst0", timeout=1000, raise_on_err=None, device_name="Network Device", shortname=None,
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209 portmap_proxy_host=None, portmap_proxy_port=rpc.PMAP_PORT, use_vxi_locking=True):
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210
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211 self.raise_on_err=raise_on_err
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212 self.lid=None
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213 self.timeout=timeout
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214 self.device_name=device_name
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215 self.device_sicl_name=device
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216 self.host=host
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217 self.portmap_proxy_host=portmap_proxy_host
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218 self.portmap_proxy_port=portmap_proxy_port
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219 self.core=None
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220 self.abortChannel=None
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221 self.mux=None #default is no multiplexer active
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222 self.use_vxi_locking=use_vxi_locking
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223
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224 if shortname is None:
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225 self.shortname=device_name.strip().replace(' ','').replace('\t','')
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226 else:
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227 self.shortname=shortname.strip().replace(' ','').replace('\t','')
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228
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229 if threads:
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230 self.threadlock=threading.RLock()
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231
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232 try:
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233 self.reconnect()
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234
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235 except VXI_11_Transient_Error:
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236 self.log_exception("Initial connect failed... retry later")
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237
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238 def setup_mux(self, mux=None, global_name=None):
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239 self.mux=mux
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240 self.global_mux_name=global_name
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241
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242 def command(self, id, pack, unpack, arglist, ignore_connect=0):
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243 #print "command() id = " + str(id) + ", pack = " + pack
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244 if not (ignore_connect or self.connected):
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245 raise VXI_11_Device_Not_Connected
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246
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247 #command has been made atomic, so that things like get_status_byte can be done
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248 #in a multi-threaded environment without needed a full vxi-11 lock to make it safe
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249 if threads:
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250 self.threadlock.acquire() #make this atomic
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251
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252 self._setup_core_packing(pack, unpack)
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253
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254 try:
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255 try:
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256 result= self.core.make_call(id, arglist, self._list_packer, self._list_unpacker)
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257 except (RuntimeError, EOFError):
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258 #RuntimeError is thrown by recvfrag if the xid is off... it means we lost data in the pipe
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259 #EOFError is thrown if the packet isn't full length, as usually happens when ther is garbage in the pipe read as a length
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260 #so vacuum out the socket, and raise a transient error
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261 rlist=1
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262 ntotal=0
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263 while(rlist):
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264 rlist, wlist, xlist=select.select([self.core.sock],[],[], 1.0)
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265 if rlist:
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266 ntotal+=len(self.core.sock.recv(10000) )#get some data from it
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267 raise VXI_11_Stream_Sync_Lost("sync", ntotal)
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268 finally:
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269 if threads:
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270 self.threadlock.release() #let go
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271
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272 err=result[0]
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273
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274 if err and self.raise_on_err:
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275 e=_VXI_11_enumerated_exceptions #common, correctable exceptions
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56
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276 if err in e:
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19
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277 raise e[err](err) #raise these exceptions explicitly
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278 else:
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279 raise VXI_11_Error(err) #raise generic VXI_11 exception
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280
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281 return result
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282
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283 def do_timeouts(self, timeout, lock_timeout, channel=None):
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284
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285 if channel is None:
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286 channel=self.core
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287
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288 flags=0
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289 if timeout is None:
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290 timeout=self.timeout
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291
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292 if not lock_timeout and hasattr(self,"default_lock_timeout"):
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293 lock_timeout=self.default_lock_timeout
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294
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295 if lock_timeout:
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296 flags |= 1 # append waitlock bit
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297
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298 if channel:
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299 channel.select_timeout_seconds=0.5+1.5*max(timeout, lock_timeout)/1000.0 #convert ms to sec, and be generous on hard timeout
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300
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301 return flags, timeout, lock_timeout
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302
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303 def reconnect(self): #recreate a broken connection
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304 """reconnect() creates or recreates our main connection. Useful in __init__ and in complete communications breakdowns.
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305 If it throws a VXI_11_Transient_Error, the connection exists, but the check_idn() handshake or post_init() failed."""
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306
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307 self.connected=0
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308
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309 if self.core:
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310 self.core.close() #if this is a reconnect, break old connection the hard way
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311 if self.abortChannel:
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312 self.abortChannel.close()
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313
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314 self.core=rpc.TCPClient(self.host, 395183, 1,
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315 portmap_proxy_host=self.portmap_proxy_host,
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316 portmap_proxy_port=self.portmap_proxy_port)
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317
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318 self._core_packers, self._core_unpackers=self._link_xdr_defs(self.core) #construct xdr data type definitions for the core
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319 #print "_core_packers now " + str(self._core_packers)
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320
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321 err, self.lid, self.abortPort, self.maxRecvSize=self.command(
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322 10, "create_link","create_link", (0, 0, self.timeout, self.device_sicl_name), ignore_connect=1) #execute create_link
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323 if err: #at this stage, we always raise exceptions since there isn't any way to bail out or retry reasonably
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324 raise VXI_11_Error(err)
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325
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326 self.maxRecvSize=min(self.maxRecvSize, 1048576) #never transfer more than 1MB at a shot
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327
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328 if self.OneWayAbort:
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329 #self.abort_channel=OneWayAbortClient(self.host, 395184, 1, self.abortPort)
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330 self.abort_channel=rpc.RawUDPClient(self.host, 395184, 1, self.abortPort)
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331 else:
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332 self.abort_channel=RawTCPClient(self.host, 395184, 1, self.abortPort)
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333
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334 connection_dict[self.lid]=(self.device_name, weakref.ref(self))
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335
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336 self.locklevel=0
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337
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338 self.connected=1
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339
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340 self.check_idn()
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341 self.post_init()
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342
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343
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344 def abort(self):
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345
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346 self.abort_channel.select_timeout_seconds=self.timeout/1000.0 #convert to seconds
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347 try:
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348 err=self.abort_channel.make_call(1, self.lid, self.abort_channel.packer.pack_int, self.abort_channel.unpacker.unpack_int) #abort
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349 except EOFError:
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350 raise VXI_11_RPC_EOF("eof")
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351
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352 if err and self.raise_on_err:
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353 raise VXI_11_Error( err)
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354 return err
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355
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356 def disconnect(self):
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357 if self.connected:
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358 try:
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359 err, =self.command(23, "id", "error", (self.lid,)) #execute destroy_link
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360 except:
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361 self.log_traceback() #if we can't close nicely, we'll close anyway
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362
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363 self.connected=0
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364 del connection_dict[self.lid]
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365 self.lid=None
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366 self.core.close()
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367 self.abort_channel.close()
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368 del self.core, self.abort_channel
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369 self.core=None
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370 self.abortChannel=None
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|
371
|
|
|
372 def __del__(self):
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|
|
373 if self.lid is not None:
|
|
|
374 self.raise_on_err=0 #no exceptions here from simple errors
|
|
|
375 try:
|
|
|
376 self.abort()
|
|
|
377 except VXI_11_Error:
|
|
|
378 pass
|
|
|
379 try:
|
|
|
380 self.disconnect()
|
|
|
381 except VXI_11_Error:
|
|
|
382 pass
|
|
|
383
|
|
|
384
|
|
|
385
|
|
|
386 def write(self, data, timeout=None, lock_timeout=0):
|
|
|
387 """err, bytes_sent=write(data [, timeout] [,lock_timeout]) sends data to device. See do_timeouts() for
|
|
|
388 semantics of timeout and lock_timeout"""
|
|
|
389
|
|
|
390 flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
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|
|
391 base=0
|
|
|
392 end=len(data)
|
|
|
393 while base<end:
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|
|
394 n=end-base
|
|
|
395 if n>self.maxRecvSize:
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|
|
396 xfer=self.maxRecvSize
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|
|
397 else:
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|
|
398 xfer=n
|
|
|
399 flags |= 8 #write end on last byte
|
|
|
400
|
|
|
401 err, count=self.command(11, "write", "write", (self.lid, timeout, lock_timeout, flags, data[base:base+xfer]))
|
|
|
402 if err: break
|
|
|
403 base+=count
|
|
|
404 return err, base
|
|
|
405
|
|
|
406 def read(self, timeout=None, lock_timeout=0, count=None, termChar=None):
|
|
|
407 """err, reason, result=read([timeout] [,lock_timeout] [,count] [,termChar]) reads up to count bytes from the device,
|
|
|
408 ending on count, EOI or termChar (if specified). See do_timeouts() for semantics of the timeouts. \n
|
|
|
409 the returned reason is an inclusive OR of 3 bits (per the VXI-11 specs section B.6.4.device_read):
|
|
|
410 Bit 2 = END/EOI received,
|
|
|
411 bit 1 = Terminating Character received,
|
|
|
412 bit 0 = full requested byte count received.
|
|
|
413 """
|
|
|
414 flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
|
|
|
415
|
|
|
416 if termChar is not None:
|
|
|
417 flags |= 128 # append termchrset bit
|
|
|
418 act_term=termChar
|
|
|
419 else:
|
|
|
420 act_term=0
|
|
|
421
|
|
|
422 accumdata=""
|
|
|
423 reason=0
|
|
|
424 err=0
|
|
|
425 accumlen=0
|
|
|
426
|
|
|
427 while ( (not err) and (not (reason & 6) ) and
|
|
|
428 ( (count is None) or (accumlen < count)) ): #wait for END or CHR reason flag or count
|
|
|
429
|
|
|
430 readcount=self.maxRecvSize
|
|
|
431 if count is not None:
|
|
|
432 readcount=min(readcount, count-accumlen)
|
|
|
433 err, reason, data = self.command(12, "read","read", (self.lid, readcount, timeout, lock_timeout, flags, act_term))
|
|
|
434 accumdata+=data
|
|
|
435 accumlen+=len(data)
|
|
|
436 #print err, reason, len(data), len(accumdata)
|
|
|
437
|
|
|
438 return err, reason, accumdata
|
|
|
439
|
|
|
440 def generic(self, code, timeout, lock_timeout):
|
|
|
441 flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
|
|
|
442
|
|
|
443 err, = self.command(code, "generic", "error", (self.lid, flags, timeout, lock_timeout))
|
|
|
444
|
|
|
445 return err
|
|
|
446
|
|
|
447 def trigger(self, timeout=None, lock_timeout=0):
|
|
|
448 return self.generic(14, timeout, lock_timeout)
|
|
|
449
|
|
|
450 def clear(self, timeout=None, lock_timeout=0):
|
|
|
451 return self.generic(15, timeout, lock_timeout)
|
|
|
452
|
|
|
453 def remote(self, timeout=None, lock_timeout=0):
|
|
|
454 return self.generic(16, timeout, lock_timeout)
|
|
|
455
|
|
|
456 def local(self, timeout=None, lock_timeout=0):
|
|
|
457 return self.generic(17, timeout, lock_timeout)
|
|
|
458
|
|
|
459 def read_status_byte(self, timeout=None, lock_timeout=0):
|
|
|
460 flags, timeout, lock_timeout=self.do_timeouts(timeout, lock_timeout)
|
|
|
461
|
|
|
462 err, status = self.command(13, "generic","read_stb", (self.lid, flags, timeout, lock_timeout))
|
|
|
463
|
|
|
464 return err, status
|
|
|
465
|
|
|
466 def lock(self, lock_timeout=0):
|
|
|
467 """lock() acquires a lock on a device and the threadlock. If it fails it leaves the connection cleanly unlocked.
|
|
|
468 If self.use_vxi_locking is false, it acquires only a thread lock locally, and does not really lock the vxi-11 device.
|
|
|
469 This is useful if only one process is talking to a given device, and saves time."""
|
|
|
470 err=0
|
|
|
471 if threads:
|
|
|
472 self.threadlock.acquire()
|
|
|
473
|
|
|
474 if self.use_vxi_locking and self.locklevel==0:
|
|
|
475 flags, timeout, lock_timeout=self.do_timeouts(0, lock_timeout)
|
|
|
476 try:
|
|
|
477 if self.mux: self.mux.lock_connection(self.global_mux_name)
|
|
|
478 try:
|
|
|
479 err, = self.command(18, "lock","error", (self.lid, flags, lock_timeout))
|
|
|
480 except:
|
|
|
481 if self.mux: self.mux.unlock_connection(self.global_mux_name)
|
|
|
482 raise
|
|
|
483 except:
|
|
|
484 if threads:
|
|
|
485 self.threadlock.release()
|
|
|
486 raise
|
|
|
487
|
|
|
488 if err:
|
|
|
489 if threads:
|
|
|
490 self.threadlock.release()
|
|
|
491 else:
|
|
|
492 self.locklevel+=1
|
|
|
493 return err
|
|
|
494
|
|
|
495 def is_locked(self):
|
|
|
496 return self.locklevel > 0
|
|
|
497
|
|
|
498 def unlock(self, priority=0):
|
|
|
499 """unlock(priority=0) unwinds one level of locking, and if the level is zero, really unlocks the device.
|
|
|
500 Calls to lock() and unlock() should be matched. If there is a danger that they are not, due to bad
|
|
|
501 exception handling, unlock_completely() should be used as a final cleanup for a series of operations.
|
|
|
502 Setting priority to non-zero will bias the apparent last-used time in a multiplexer (if one is used),
|
|
|
503 so setting priority to -10 will effectively mark this channel least-recently-used, while setting it to
|
|
|
504 +2 will post-date the last-used time 2 seconds, so for the next 2 seconds, the device will be hard to kick
|
|
|
505 out of the channel cache (but not impossible).
|
|
|
506 """
|
|
|
507
|
|
|
508 self.locklevel-=1
|
|
|
509 assert self.locklevel>=0, "Too many unlocks on device: "+self.device_name
|
|
|
510
|
|
|
511 err=0
|
|
|
512 try:
|
|
|
513 if self.use_vxi_locking and self.locklevel==0:
|
|
|
514 try:
|
|
|
515 err, = self.command(19, "id", "error", (self.lid, ))
|
|
|
516 finally:
|
|
|
517 if self.mux:
|
|
|
518 self.mux.unlock_connection(self.global_mux_name, priority) #this cannot fail, no try needed (??)
|
|
|
519 elif priority and self.mux:
|
|
|
520 #even on a non-final unlock, a request for changed priority is always remembered
|
|
|
521 self.mux.adjust_priority(self.global_mux_name, priority)
|
|
|
522 finally:
|
|
|
523 if threads:
|
|
|
524 self.threadlock.release()
|
|
|
525
|
|
|
526 return err
|
|
|
527
|
|
|
528 def unlock_completely(self, priority=0):
|
|
|
529 "unlock_completely() forces an unwind of any locks all the way back to zero for error cleanup. Only exceptions thrown are fatal."
|
|
|
530 if threads:
|
|
|
531 self.threadlock.acquire() #make sure we have the threadlock before we try a (possibly failing) full lock
|
|
|
532 try:
|
|
|
533 self.lock() #just to be safe, we should already hold one level of lock!
|
|
|
534 except VXI_11_Locked_Elsewhere:
|
|
|
535 pass #this is often called on error cleanup when we don't already have a lock, and we don't really care if we can't get it
|
|
|
536 except VXI_11_Error:
|
|
|
537 self.log_exception("Unexpected trouble locking in unlock_completely(): ")
|
|
|
538
|
|
|
539 if threads:
|
|
|
540 self.threadlock._RLock__count += (1-self.threadlock._RLock__count)
|
|
|
541 #unwind to single lock the fast way, and make sure this variable really existed, to shield against internal changes
|
|
|
542 self.locklevel=1 #unwind our own counter, too
|
|
|
543 try:
|
|
|
544 self.unlock(priority)
|
|
|
545 except VXI_11_Device_Not_Locked:
|
|
|
546 pass #if we couldn't lock above, we will probably get another exception here, and don't care
|
|
|
547 except VXI_11_Transient_Error:
|
|
|
548 self.log_exception("Unexpected trouble unlocking in unlock_completely(): ")
|
|
|
549 except VXI_11_Error:
|
|
|
550 self.log_exception("Unexpected trouble unlocking in unlock_completely(): ")
|
|
|
551 raise
|
|
|
552
|
|
|
553 def transaction(self, data, count=None, lock_timeout=0):
|
|
|
554 """err, reason, result=transaction(data, [, count] [,lock_timeout]) sends data and waits for a response.
|
|
|
555 It is guaranteed to leave the lock level at its original value on exit,
|
|
|
556 unless KeyboardInterrupt breaks the normal flow. If count isn't provided, there is no limit to how much data will be accepted.
|
|
|
557 See do_timeouts() for semantics on lock_timeout."""
|
|
|
558
|
|
|
559 self.lock(lock_timeout)
|
|
|
560 reason=None
|
|
|
561 result=None
|
|
|
562 try:
|
|
|
563 err, write_count = self.write(data)
|
|
|
564
|
|
|
565 if not err:
|
|
|
566 err, reason, result = self.read(count=count)
|
|
|
567 finally:
|
|
|
568 self.unlock()
|
|
|
569
|
|
|
570 return err, reason, result
|
|
|
571
|
|
|
572 def check_idn(self):
|
|
|
573 'check_idn() executes "*idn?" and aborts if the result does not start with self.idn_head'
|
|
|
574 if hasattr(self,"idn"):
|
|
|
575 return #already done
|
|
|
576 if hasattr(self,"idn_head") and self.idn_head is not None:
|
|
|
577
|
|
|
578 self.lock()
|
|
|
579 try:
|
|
|
580 self.clear()
|
|
|
581 err, reason, idn = self.transaction("*idn?")
|
|
|
582 finally:
|
|
|
583 self.unlock()
|
|
|
584
|
|
|
585 check=idn.find(self.idn_head)
|
|
|
586 self.idn=idn.strip() #save for future reference info
|
|
|
587 if check:
|
|
|
588 self.disconnect()
|
|
|
589 assert check==0, "Wrong device type! expecting: "+self.idn_head+"... got: "+self.idn
|
|
|
590 else:
|
|
|
591 self.idn="Device *idn? not checked!"
|
|
|
592
|
|
|
593 import copy
|
|
|
594
|
|
|
595 class device_thread:
|
|
|
596
|
|
|
597 if threads:
|
|
|
598 Thread=threading.Thread #by default, use canonical threads
|
|
|
599
|
|
|
600 def __init__(self, connection, main_sleep=1.0, name="Device"):
|
|
|
601 self.running=0
|
|
|
602 self.main_sleep=main_sleep
|
|
|
603 self.__thread=None
|
|
|
604 self.__name=copy.copy(name) #make a new copy to avoid a possible circular reference
|
|
|
605 self.__wait_event=threading.Event()
|
|
|
606 self.set_connection(connection)
|
|
|
607
|
|
|
608 def set_connection(self, connection):
|
|
|
609 #keep only a weak reference, so the thread cannot prevent the device from being deleted
|
|
|
610 #such deletion creates an error when the thread tries to run, but that's OK
|
|
|
611 #this allows the device_thread to be used as a clean mix-in class to a vxi_11 connection
|
|
|
612 self.__weak_connection=weakref.ref(connection)
|
|
|
613
|
|
|
614 def connection(self):
|
|
|
615 return self.__weak_connection() #dereference weak reference
|
|
|
616
|
|
|
617 def handle_lock_error(self):
|
|
|
618 "handle_lock_error can be overridden to count failures and do something if there are too many"
|
|
|
619 self.connection().log_exception(self.name+": Error while locking device")
|
|
|
620
|
|
|
621 def onepass(self):
|
|
|
622 connection=self.connection()
|
|
|
623
|
|
|
624 try:
|
|
|
625 connection.lock()
|
|
|
626 except VXI_11_Transient_Error:
|
|
|
627 self.handle_lock_error()
|
|
|
628 return
|
|
|
629
|
|
|
630 try:
|
|
|
631 self.get_data()
|
|
|
632 except:
|
|
|
633 connection.log_traceback('Uncaught exception in get_data()')
|
|
|
634 try:
|
|
|
635 connection.clear()
|
|
|
636 except:
|
|
|
637 connection.log_exception('failed to clear connection after error')
|
|
|
638 self.run=0
|
|
|
639
|
|
|
640 connection.unlock()
|
|
|
641
|
|
|
642 def monitor(self):
|
|
|
643 self.connection().log_info("Monitor loop entered")
|
|
|
644 while(self.run):
|
|
|
645 try:
|
|
|
646 self.onepass()
|
|
|
647 self.__wait_event.wait(self.main_sleep) #wait until timeout or we are cancelled
|
|
|
648 except KeyboardInterrupt:
|
|
|
649 self.connection().log_error("Keyboard Interrupt... terminating")
|
|
|
650 self.run=0
|
|
|
651 except:
|
|
|
652 self.connection().log_traceback()
|
|
|
653 self.run=0
|
|
|
654
|
|
|
655 self.running=0
|
|
|
656 self.connection().unlock_completely()
|
|
|
657
|
|
|
658 def run_thread(self):
|
|
|
659 if not self.running: #if it's already running, just keep it up.
|
|
|
660 self.run=1
|
|
|
661 self.__thread=self.Thread(target=self.monitor, name=self.__name)
|
|
|
662 self.__wait_event.clear() #make sure we don't fall through immediately
|
|
|
663 self.__thread.start()
|
|
|
664 self.running=1
|
|
|
665
|
|
|
666 def get_monitor_thread(self):
|
|
|
667 return self.__thread
|
|
|
668
|
|
|
669 def stop_thread(self):
|
|
|
670 if self.running:
|
|
|
671 self.run=0
|
|
|
672 self.__wait_event.set() #cancel any waiting
|
