Allow snooping on all methods of a class

I didn’t find a way to easily snoop on all the methods of a class without adding the decorator to every single method. Below is an outline of a way to do it with a metaclass. There was an issue overwriting the magic/dunder methods (AttributeError: type object 'SnoopedMetaClass' has no attribute '__code__'), but for everything else it works fine.

import pysnooper

class SnoopMetaClass(type):
    """Converts every method to a snooped method"""
    def __new__(cls, name, bases, attrs, **kwargs):
        # Create the instance like normal
        instance = super().__new__(cls, name, bases, attrs)

        # If the class has a "snoop_kwargs" class attribute, get it here
        # so we can forward it to pysnooper.snoop. Set it to an empty dict by default.
        kwargs = attrs.get("snoop_kwargs", {})

        # Iterate over every attribute and find the ones that are methods
        for attr in dir(instance):
            # Certain magic methods do not like to be overridden by the snooped version
            if attr.startswith("__"):
                continue

            # Override the value with a snooped one if it is callable
            value = getattr(instance, attr)
            if callable(value):
                snooped = pysnooper.snoop(**kwargs)(value)
                setattr(instance, attr, snooped)
        return instance




class MyClass(metaclass=SnoopMetaClass):
    snoop_kwargs = {"output": "log.txt"}

   def __init__(self):
       """Will not be snooped on since it is a magic method"""

    def my_method(self):
        """Normal method, will be snooped on"""

    def my_other_method(self):
        """Normal method, will be snooped on"""

[cool-RR]

This is a cute idea. My priority is to keep the interface as simple as possible, so if you’d like me to merge it, I’d like you to modify it so it’s a decorator on the class rather than a metaclass. Submit a PR like that, with tests and documentation, and I’ll likely merge it.

[alexmojaki]

Another problem:

import pysnooper


@pysnooper.snoop()
class A:
    @pysnooper.snoop()
    def foo(self):
        pass


A().foo()

Output:

Source path:... /Users/alexhall/Desktop/python/snoop/venv/lib/python3.7/site-packages/pysnooper/tracer.py
Starting var:.. args = (<__main__.A object at 0x104f39b38>,)
Starting var:.. kwargs = {}
Starting var:.. function = <function A.foo at 0x105557950>
Starting var:.. self = <pysnooper.tracer.Tracer object at 0x104f39ac8>
21:27:56.248748 call       250         def simple_wrapper(*args, **kwargs):
21:27:56.255392 line       251             with self:
21:27:56.260776 line       252                 return function(*args, **kwargs)
    Source path:... /Users/alexhall/Library/Preferences/PyCharm2019.2/scratches/scratch_441.py
    Starting var:.. self = <__main__.A object at 0x104f39b38>
    21:27:56.262119 call         7     def foo(self):
    21:27:56.262523 line         8         pass
    21:27:56.262618 return       8         pass
    Return value:.. None
Call ended by exception