Error on sys.modules?

Ignition
1

I’ve been trying to use the inspect module in a script, however, upon using “inspect.stack()” I would get this error:

[code]Traceback (most recent call last):
File “event:actionPerformed”, line 2, in
File “C:\Documents and Settings\andrey.gueorguiev\Application Data\Sun\Java\Deployment\cache\FPMI\script_lib2\Lib\inspect.py”, line 901, in stack
return getouterframes(sys._getframe(1), context)
File “C:\Documents and Settings\andrey.gueorguiev\Application Data\Sun\Java\Deployment\cache\FPMI\script_lib2\Lib\inspect.py”, line 882, in getouterframes
framelist.append((frame,) + getframeinfo(frame, context))
File “C:\Documents and Settings\andrey.gueorguiev\Application Data\Sun\Java\Deployment\cache\FPMI\script_lib2\Lib\inspect.py”, line 853, in getframeinfo
filename = getsourcefile(frame) or getfile(frame)
File “C:\Documents and Settings\andrey.gueorguiev\Application Data\Sun\Java\Deployment\cache\FPMI\script_lib2\Lib\inspect.py”, line 406, in getsourcefile
if hasattr(getmodule(object, filename), ‘loader’):
File “C:\Documents and Settings\andrey.gueorguiev\Application Data\Sun\Java\Deployment\cache\FPMI\script_lib2\Lib\inspect.py”, line 453, in getmodule
main = sys.modules[‘main’]
KeyError: ‘main’

Ignition v7.5.6 (b1317)
Java: Sun Microsystems Inc. 1.6.0_38[/code]

The error seems to be coming from sys.modules, because “main” is not a part of it.
Is there any way I can get around this error, or am I just doing something wrong?

2

Honestly I’m not familiar with the inspect module. I’m guessing it is incompatible with the way we use scripting.

3

Fixed by adding this before the calling function:

class VirtualModule(object):
	def __init__(self,name):
		import sys
		sys.modules[name]=self
	def __getattr__(self,name):
		return globals()[name]
VirtualModule("__main__")
1 Like
4

Well that response came in handy for me some 11 years later with Ignition v8.1.31.
I was interested in using the inspect module as a way to determine the name of the current function and/or the calling function for debug log entries..

Code like this would work in Script Console however any use of inspect.stack() in a Gateway Script. would cause the KeyError: '__main__' exception.

import inspect
def whoami():
   return inspect.stack()[1][3]
def whosdaddy():
   return inspect.stack()[2][3]

Adding the VirtualModule makes inspect.stack() behave better.
I was also able to meet my need by avoiding inspect.stack() using this instead, without the Virtual Module.

def whoami():
	return inspect.currentframe().f_back.f_code.co_name
def whosdaddy():
	return inspect.currentframe().f_back.f_back.f_code.co_name