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Repacking or wrapping of imported error or exception types in python3 modules

I have this module A that might raise an exception from an imported module B. Can I "wrap" or "repack" the exception so that I can handle the exception in the importing script without having to import B?
A.py:
import B
def do_something(parameters):
try:
B.function(**parameters)
except B.some_exception as eee:
raise wrapper(eee)
script.py
import A
try:
do_something("glorious parameter")
except B.wrapped_exception:
handling()

You could just import the exception from B like
from B import some_exception
or add a general exception catch with some other logic, like a matching message, to check if it the specific exception like
try:
do_something("glorious parameter")
except Exception as e:
if str(e) == "Matching message":
handling()
else:
raise e
However, bare exceptions are usually not recommended because they indiscriminately catch everything (What is wrong with using a bare 'except'?) so I would go with your original solution or the first suggestion.
Edit:
I re-read your issue and I think I got what you meant. You can chain exceptions with the keyword from and raise some general error like ValueError such as:
def do_something(parameters):
try:
B.function(**parameters)
except B.some_exception as eee:
raise ValueError("Wrapped exception") from eee
and then catch the ValueError as usual.
See: Python "raise from" usage

Python Error handling cant except error's

I am trying this code:
try:
res = subprocess.Popen('bgpq3 -4 {} -m 24 -l {}'.format('MAIyNT-
AS38082','12414'), shell=True,
universal_newlines=True,
stdout=subprocess.PIPE).communicate()[0]
except Exception:
print("Wrong")
#do this code
The output is ?
ERROR:Unable to parse prefix 'MAIyNT-AS38082', af=2 (inet), ret=0
ERROR:Unable to parse prefix MAIyNT-AS38082
ERROR:Unable to add prefix MAIyNT-AS38082 (bad prefix or address-family)
so i am not able to use Error handling!!
Any Idea?

when you write except Exception: you are not catching all the exception: the system exit errors and OS errors (as BaseException, SystemExit, KeyboardInterrupt and GeneratorExit) are excluded.
Most of the exceptions of subprocess are OSError.
Since you did not report the full traceback of the error, I may only assume that you're getting one of these errors, and you can catch them using:
except subprocess.CalledProcessError:
or
except OSError:
as PEP 8 suggest, you should NOT use except: alone, even if it will work in your case.
As a rule of thumb, always catch the exact exception you espect to be raised!

You're only handling errors of type exception here. You only need to use except:. This way you're catching all errors that occur in the code.
try:
#your code
except Exception as e:
#handle the exception
For more information refer to the docs I got from a quick google ;)

How many exceptions are possible when reading a json in Python/django?

I have:
MY_PATH_DIR = 'path/to/my/json/file.json'
try:
with open(MY_PATH_DIR, 'r') as f:
MY_PATH_DIR = json.load(f)
except IOError, RuntimeError, ValueError:
pass
except PermissionDenied:
pass
And I want to catch all possible errors. With
IOError - I am catching errors when the file doesn't exist or has a
syntax error (non valid JSON).
RuntimeError - couldn't test it but I think that makes sense from the
documentation in case of an unexpected error
ValueError - I got from here in case nothing got returned
PermissionDenied - is a specific Django error
Are there any other Exceptions that would make sense? I'm not sure if OSError makes sense here. I think that would be raised earlier, right?

The purpose of capturing exceptions is to control the program's behavior when something bad happened, but in an expected way. If you are not even sure what would cause that exception happen, capturing it would only swallow the underlying programming errors you might have.
I wouldn't add as many kinds of exception as possible to that single block of code, you should only add what you care about. To take it to extreme, each line of code would yield certain exceptions but for obvious reason you couldn't do try except for all of them.
Edit:
For the sake of correctness, since you mentioned I don't want my code to break in any case, you could simply do:
try:
# json.load
except Exception as e:
print "Let's just ignore all exceptions, like this one: %s" % str(e)
This is would give you what exception happens as output.

import random
import sys
def main():
"""Demonstrate the handling of various kinds of exceptions."""
# This is like what you are doing in your code.
exceptions = IOError, RuntimeError, ValueError
try:
raise random.choice(exceptions)()
except exceptions as error:
print('Currently handling:', repr(error))
# The following is not much different from Shang Wang's answer.
try:
raise random.choice(exceptions)()
except Exception as error:
print('Currently handling:', repr(error))
# However, the following code will sometimes not handle the exception.
exceptions += SystemExit, KeyboardInterrupt, GeneratorExit
try:
raise random.choice(exceptions)()
except Exception as error:
print('Currently handling:', repr(error))
# The code can be slightly altered to take the new errors into account.
try:
raise random.choice(exceptions)()
except BaseException as error:
print('Currently handling:', repr(error))
# This does not take into account classes not in the exception hierarchy.
class Death:
pass
try:
raise Death()
except BaseException as error:
print('Currently handling:', repr(error))
# If your version of Python does not consider raising an exception from an
# instance of a class not derived from the BaseException class, the way to
# get around this problem would be with the following code instead.
try:
raise Death()
except:
error = sys.exc_info()[1]
print('Currently handling:', repr(error))
if __name__ == '__main__':
main()

Print Python Exception Type (Raised in Fabric)

I'm using Fabric to automate, including the task of creating a directory. Here is my fabfile.py:
#!/usr/bin/env python
from fabric.api import *
def init():
try:
local('mkdir ./www')
except ##what exception?##:
#print exception name to put in above
Run fab fabfile.py and f I already have ./www created an error is raised, but I don't know what kind, so I don't know how to handle the error yet. Fabric only prints out the following:
mkdir: cannot create directory ‘./www’: File exists
Fatal error: local() encountered an error (return code 1) while executing 'mkdir ./www'
Aborting.
What I want to do is be able to find out the error type so that I can except my errors properly without blanket statements. It would be really helpful if an answer does not just tell me how to handle a mkdir exception, but print (or otherwise find the name to) any exception I may run into down the line (mkdir is just an example).
Thank you!

The issue is that fabric uses subprocess for doing these sorts of things. If you look at the source code for local you can see it doesn't actually raise an exception. It calls suprocess.Popen and uses communicate() to read stdout and stderr. If there is a non-zero return code then it returns a call to either warn or abort. The default is abort. So, to do what you want, try this:
def init():
with settings(warn_only=True):
local('mkdir ./www')
If you look at the source for abort, it looks like this:
10 def abort(msg):
21 from fabric.state import output
22 if output.aborts:
23 sys.stderr.write("\nFatal error: %s\n" % str(msg))
24 sys.stderr.write("\nAborting.\n")
25 sys.exit(1)
So, the exception would be a SystemExit exception. While you could catch this, the proper way to do it is outlined above using settings.

It is nothing to handle with exception, it is from the fabric api
try to set the entire script's warn_only setting to be true with
env.warn_only = True

Normally, when you get an uncaught exception, Python will print the exception type along with the error message:
>>> raise IOError("Error message.")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IOError: Error message.
If that's not happening, you're probably not getting an exception at all.
If you really want to catch an arbitrary exception and print it, you want to catch Exception or BaseException. BaseException will include even things like KeyboardInterrupt, though, so be careful with that.
def init():
try:
local('mkdir ./www')
except BaseException as e:
print "local() threw a", type(e).__name__
raise # Reraise the exception

In general:
try:
some_code()
except Exception, e:
print 'Hit An Exception', e
raise
Will tell you what the exception was but if you are not planning on actually handling some of the exceptions then simply getting rid of the try: except: lines will have exactly the same effect.
Also if you run your code under a debugger then you can look at the exception(s) that you hit in more detail.

def init():
try:
local('mkdir ./www')
except Exception as e:
print e.__class__.__name__
That's all there is to it!
edit: Just re-read your question and realized that my code would only print "Fatal" in your case. It looks like fabric is throwing an error and returning their own error code so you would have to look at the documentation. I don't have any experience with fabric so I'd suggest to look here if you haven't already. Sorry if this isn't helpful!

Catch any error in Python [duplicate]

This question already has answers here:
How can I write a `try`/`except` block that catches all exceptions?
(10 answers)
Closed 1 year ago.
Is it possible to catch any error in Python? I don't care what the specific exceptions will be, because all of them will have the same fallback.

Using except by itself will catch any exception short of a segfault.
try:
something()
except:
fallback()
You might want to handle KeyboardInterrupt separately in case you need to use it to exit your script:
try:
something()
except KeyboardInterrupt:
return
except:
fallback()
There's a nice list of basic exceptions you can catch here. I also quite like the traceback module for retrieving a call stack from the exception. Try traceback.format_exc() or traceback.print_exc() in an exception handler.

try:
# do something
except Exception, e:
# handle it
For Python 3.x:
try:
# do something
except Exception as e:
# handle it

You might want also to look at sys.excepthook:
When an exception is raised and uncaught, the interpreter calls
sys.excepthook with three arguments, the exception class, exception
instance, and a traceback object. In an interactive session this
happens just before control is returned to the prompt; in a Python
program this happens just before the program exits. The handling of
such top-level exceptions can be customized by assigning another
three-argument function to sys.excepthook.
Example:
def except_hook(type, value, tback):
# manage unhandled exception here
sys.__excepthook__(type, value, tback) # then call the default handler
sys.excepthook = except_hook

Quoting the bounty text:
I want to be able to capture ANY exception even weird ones like
keyboard interrupt or even system exit (e.g. if my HPC manger throws
an error) and get a handle to the exception object e, whatever it
might be. I want to process e and custom print it or even send it by
email
Look at the exception hierarchy, you need to catch BaseException:
BaseException
+-- SystemExit
+-- KeyboardInterrupt
+-- GeneratorExit
+-- Exception
This will capture KeyboardInterrupt, SystemExit, and GeneratorExit, which all inherit from BaseException but not from Exception, e.g.
try:
raise SystemExit
except BaseException as e:
print(e.with_traceback)

Not mentioning the type of exception you want to handle itself does the job.
Try this:
try:
#code in which you expect an exception
except:
#prints the exception occured
if you want to know the type of exception that occurred:
try:
# code in which you expect an exception
except Exception as e:
print(e)
# for any exception to be catched
print(type(e))
# to know the type of exception.
for detailed explanation go trough this
https://www.tutorialspoint.com/python/python_exceptions.htm

# in python 3
# if you want the error
try:
func()
except Exception as e:
exceptionFunc(e)
# if you simply want to know an error occurs
try:
func()
except:
exceptionFunc()
# if you don't even wanna do anything
try:
func()
except:
pass

The following only worked for me (both in PY2 and PY3):
try:
# (Anything that produces any kind of error)
except:
ertype = sys.exc_info()[0] # E.g. <class 'PermissionError'>
description = sys.exc_info()[1] # E.g. [Errno 13] Permission denied: ...
# (Handle as needed )

Built-In Exceptions in Python
Built-In exception classes are divided into Base error classes from which the error classes are defined and Concrete error classes which define exceptions which you are more likely to see time to time.
The more detailed document about the buit-In exception can be found in [https://docs.python.org/3/library/exceptions.html]
Custom Exceptions
It is used to fit your specific application situation. For example, you can create your own exception as RecipeNotValidError as the recipe is not valid in your class for developing a cooking app.
Implementation
class RecipeNotValidError(Exception):
def __init__(self):
self.message = "Your recipe is not valid"
try:
raise RecipeNotValidError
except RecipeNotValidError as e:
print(e.message)
These are custom exceptions that are not defined in the standard library. The steps you can follow to create custom classes are :
Subclass the Exception class.
Create a new Exception class of your choice.
Write your code and use the try...except flow to capture and handle your custom exception.