wrap-logger 0.1.0

A library to wrap around objects and modules in Python and log property accesses and calls

Wrap Logger

A library to wrap around objects and modules in Python and log property accesses and calls.

Rationale

In some cases when programming, errors can break things to the point where you have no idea where things went wrong, for example, crashing the runtime environment before a backtrace can be printed. In these cases, it can be extremely useful to log changes to data that are potentially related to the issue, but doing so can be tedious and slow. I needed a simple solution to easily inject logging into objects, and so I created wrap-logger.

Usage

Using wrap-logger is simple. Simply call the wrap function, which will return a wrapped version.

With a module

import foo
from wrap_logger import wrap

# Now all function calls and global reads/writes will be logged
foo = wrap(foo)

With a class

from wrap_logger import wrap

class Simple:
    """Simple class for testing purposes"""
    def __init__(self) -> None:
        self.value = 42

    def __repr__(self) -> str:
        return 'simple'

    def echo(self, value: str) -> str:
        return value


obj = wrap(Simple())


# Getting a property causes things to be logged
variable = obj.value
# [WRAP LOG] > Get  simple.value
# [WRAP LOG] < Get  simple.value: gave 42

# Same for setting properties
obj.value = 43
# [WRAP LOG] > Set  simple.value: 42 -> 43
# [WRAP LOG] < Set  simple.value

# And calling functions
obj.echo('hello world')
# [WRAP LOG] > Call simple.echo('hello world')
# [WRAP LOG] < Call simple.echo('hello world'): returned 'hello world'

Without Pip

wrap-logger requires no dependencies, and can even function with some parts of the standard library missing. Simply head over to the releases tab where the wrap-logger.zip file is attached, then extract it into a new folder within your project, where you can import it easily. You should then be able to use it normally, importing it from your desired location.

Implementation details

wrap-logger wraps objects in a WrapLogger class. Although the class does override the __class__ property so as to fool isinstance checks, fooling the type function does not appear to work, so those checks may fail leading to potentially erroneous behaviour.

TODOs

wrap-logger was thrown together so I could quickly debug another project, so it is incomplete. If there is demand (hint: create an issue), I will be happy to try my hand at implementing the following features:

• Specify output file that wrap-logger prints to
• Recursive wrapping, so that attributes of attributes are also logged
• Configuration on what is/isn't logged (currently it just prints everything)
• Figure out what happens if you use wrap-logger on itself. Does it crash? Does it delete System 32? Does the space-time continuum collapse? Who knows!