How to log errors before the try- except loop in python?

Question

I am trying to implement Python's logging library for log.

I understand that if something is wrapped in try-catch loop, the exception is caught.

But in one of my example, the import is failing which is the start of the script. This is not getting logged. ( It is only printing this in Jupyter's logs)

How to log these exceptions? Looking for not wrapping the entire script in try - except loop.

Any error on Jupyter or any IDE is printed in the console, why not with logger? isnt there any such implementation

Isnt it a strech to include everything in try-catch.?? Like any error on Jupyter or any IDE is printed in the console, why not with logger? isnt there any such implementation? — Viv
– Viv, Commented Sep 12, 2017 at 12:18

magor · Accepted Answer · 2017-09-12 14:33:06Z

2

When using logger, you have to implement the logging of your errors.
In Python, errors are being logged only to the console by default.
So, if you want to use logger, you have to add your logic to catch and log your errors.

The try except block is a common way to handle import on Python.

Quoting Dive into Python:

There are a lot of other uses for exceptions besides handling actual error conditions. A common use in the standard Python library is to try to import a module, and then check whether it worked. Importing a module that does not exist will raise an ImportError exception. You can use this to define multiple levels of functionality based on which modules are available at run-time, or to support multiple platforms (where platform-specific code is separated into different modules).

The next example demonstrates how to use an exception to support platform-specific functionality.

try:
    import termios, TERMIOS                     
except ImportError:
    try:
        import msvcrt                           
    except ImportError:
        try:
            from EasyDialogs import AskPassword 
        except ImportError:
            getpass = default_getpass           
        else:                                   
            getpass = AskPassword
    else:
        getpass = win_getpass
else:
    getpass = unix_getpass

edited Sep 12, 2017 at 14:33

answered Sep 12, 2017 at 12:18

magor

72912 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Viv Over a year ago

Was looking for something without the try block.. error on Jupyter or any IDE is printed in the console, why not with logger? isnt there any such implementation?

magor Over a year ago

This is not really clear - when using logger, you have to implement the logging of your errors. Errors are being logged only to the console by default. So, if you want to use logger, you have to add your line to catch and log your errors

Gidalti · Accepted Answer · 2017-09-12 13:01:25Z

1

The difference with IDE's logs or even if you run a python file from console or terminal is that as soon as the exception is caught the script is interrupted immediately.

If you want to get the exception and do something after it happens, to log it for instance, then you need to use the "try except" block.

I don't know why you are trying to avoid using the "try except" block as it is a basic feature of the language as any other decision-making blocks ("if", "while", "for", etc.).

Try to see it as a common "if" statement:

if trying this:
    works, great!
else:
    do something with this exception

answered Sep 12, 2017 at 13:01

Gidalti

413 bronze badges

Collectives™ on Stack Overflow

How to log errors before the try- except loop in python?

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related