My Django app is currently throwing this error on one of my pages, does anyone know what it eans? I would supply more detail but I don't know what this error means so I'm not sure what the relevant files are and Django apps are rather large in the amount of code spread around so I'll post some code once I can get an idea of what this means. Thanks in advance for any help.
EDIT: I tried capturing the error and printing it like so:
EDIT: I've entered the code that's throwing the error
jobIDs is a dict containing all of the IDs of the records I want to modify
for i in jobIDs:
dateToRun = request.POST['dateToRun']
timeToRun = request.POST['timeToRun']
try:
if len(request.POST['dateToRun']) <= 0:
dateToRun = Job.objects.filter(id=jobIDs[i]).values()['whenToRun'].split(' ')[0]
if len(request.POST['timeToRun']) <= 0:
timeToRun = Job.objects.filter(id=jobIDs[i]).values()['whenToRun'].split(' ')[1]
except BaseException, e:
print str(e)
whenToRun = dateToRun + ' ' + timeToRun
Job.objects.filter(id=jobIDs[i]).update(whenToRun=whenToRun)
This produces a blank line of output (from the print in the except block), am I misunderstanding how to print out the error?
Are you executing a piece of code that may throw an exception? Perhaps a database query for something that does not exist? If so, you will need to wrap the block of code in a try/except clause. For example, if the exception is indeed a query for something that does not exist:
try:
#Block of code that throws exception
except Object.DoesNotExist:
#Handle error
Perhaps it's because you're using BaseException instead of just Exception? Try this:
try:
# Your code that may throw an exception
except Exception, e:
print str(e)
As per the Python Exception docs on BaseException:
exception BaseException
directly inherited by user-defined classes (for that, use Exception)The base class for all built-in exceptions. It is not meant to be directly inherited by user-defined classes (for that, use Exception).
Related
I want to explicitly fail the step in behave when I encounter an exception
eg. I am writing the code according to behave documentation -
from behave import *
#when('verify test fails.*?(?P<param_dict>.*)')
def test_logger(context, param_dict):
try:
logger.info("testing the logger. this is info message")
logger.info(1/0)
except Exception as e:
logger.error("arrived at exception: "+str(e))
fail("failed with exception: "+str(e))
but it throws this error:
NameError: name 'fail' is not defined
I tried other ways too, but nothing works
eg. context.failed = True (did not work either)
If I do not try to fail explicitly, final test result becomes PASS even if it goes in exception block ...which is weird.
context.failed is only an attribute set by Behave and doesn't do anything as is. It's an information attribute, and while you can use it to determine a fail-case and throw an assertion error, it will not do anything on it's own. See context.failed
As for the fail method you've mentioned, it is probably from the unittest module, as seen here. This module is used in Behave's development tests (see their Github) as well. I'll agree though, that this should be clarified in their documentation.
To fix your error you'd need to import the unittest module. To explicitly fail the step, you'd just raise the exception after you've logged your message, something like this:
except Exception as e:
logger.error("arrived at exception: "+str(e))
fail("failed with exception: "+str(e))
raise
As #Verv mentioned in their answer, a behave step will be marked as failed whenever an exception is thrown, so you could just re-raise the exception.
However, behave will show the backtrace for normal exceptions, whereas you probably just want to show a specific failure message.
For that, raise an AssertionError. In your code, that would look like this:
except Exception as e:
logger.error("arrived at exception: " + str(e))
raise AssertionError("failed with exception: " + str(e))
If behave encounters an AssertionError, it will fail the step, display the message you instantiate the error with, but not display other exception stuff.
In Python 3.x, what is the correct syntax to handle exceptions that have parameters.
I'm specifically trying to handle WriteError documented on this page.
I'm writing the code to handle it as:
except pymongo.errors.WriteError(err, code, dtls):
logging.error("DB Write Error. err={}; code={}; dtls={}".format(err, code, dtls))
This is not working.
I even had a look at the Erros and Exceptions documentation. But could not find it there.
Can you please tell me the correct way to handle these sort of exceptions?
You catch the error first, then examine its attributes (reraising the exception if it isn't one you want to handle). There is no pattern matching on the contents of the exception.
except pymongo.errors.WriteError as exc:
logging.error("DB WriteError. err={}; code={}; dtls={}".format(exc.err, exc.code, exc.dtls))
The except block just needs the exception's type. Within the block you could, of course, use its attributes if you wish:
except pymongo.errors.WriteError as e:
logging.error("DB Write Error. err={}; code={}; dtls={}".format(e.err, e.code, e.dtls))
I've been playing around with this but I can't quite seem to figure out the syntax. I'm trying to exception handle a specific exception thrown from an Amazon API lib.
It throws the exception:
class 'amazon.api.AsinNotFound'
I've tried:
except AsinNotFound
and
except amazon.api.AsinNotFound
I can handle it with just an except but I want to be able to catch this specific case if possible. If it's not I could look for the text in sys.exc_info() but that doesn't seem like a neat way of doing it.
Example:
try:
DoSomethingWithASIN
except amazon.api.AsinNotFound:
print "No ASIN"
except:
print "this part triggers instead"
I was looking to possibly try and save a traceback object and somehow pickle it to a file that I can access. An example of a use case for this is if I am submitting some python code to a farm computer to run and it fails, it would be nice to be able to open a session and access that traceback to debug the problem rather than just seeing a log of the traceback. I do not know if there is any sort of way to do this but thought it would be worth asking why it couldn't if so.
okay so you can use traceback.print_exception(type, value, traceback[, limit[, file]]) and save it in a text or json or you can refer to docs
if you find it helpful please mark it correct or upvote thanx..:)
Depending on how you've written your code, the try statement is probably your best answer. Since any error is just a class that inherits Python's builtin Exception, you can raise custom errors everywhere you need more information about a thrown error. You just need to rename your errors or pass in an appropriate string as the first argument. If you then try your code and use the except statement except CustomError as e, you can pull all the information you want out of e in the except statement as a regular instance. Example:
Your code would be:
def script():
try: codeblock
except Exception as e: raise Error1('You hit %s error in the first block'% e)
try: codeblock 2
except Exception as e: raise Error2('You hit %s error in the second block' % e)
try: script()
except Exception as e:
with open('path\to\file.txt','w') as outFile:
outFile.write(e)
The last part is really nothing more than creating your own log file, but you have to write it down somewhere, right?
As for using the traceback module mentioned above, you can get error information out of that. Any of the commands here can get you a list of tracebacks:
http://docs.python.org/2/library/traceback.html
On the otherhand, if you're trying to avoid looking at log files, the traceback module is only going to give you the same thing a log file would, in a different format. Adding your own error statements in your code gives you more information than a cryptic ValueError about what actually happened. If you print the traceback to your special error, it might give you still more information on your issue.
except ImportError as xcpt:
print "Import Error: " + xcpt.message
Gets you a deprecation warning in 2.6 because message is going away.
Stackoverflow
How should you be dealing with ImportError? (Note, this is a built-in exception, not one of my making....)
The correct approach is
xcpt.args
Only the message attribute is going away. The exception will continue to exist and it will continue to have arguments.
Read this: http://www.python.org/dev/peps/pep-0352/ which has some rational for removing the messages attribute.
If you want to print the exception:
print "Couldn't import foo.bar.baz: %s" % xcpt
Exceptions have a __str__ method defined to create a readable version of themselves. I wouldn't bother with "Import Error:" since the exception will provide that itself. If you add text to the exception, make it be something you know based on the code you were trying to execute.