Scope Injected ContextManager

A decorator/context manager that injects scope vars into a function

• A context manager decorator for Python 3
• Lets you specify variables to extract from the innner-scope (the managed scope) and will inject them into the @scope_injected_contextmanager decorated function
• acts like a defaulted function (think functools.partial)
• allows you to pass in kwargs at runtime as well

Usage

For an extensive collection of examples see tests

Functions decorated with @scope_injected_contextmanager becomes context managers that can be invoked in two different ways:

As an instance

from scope_injected_contextmanager import scope_injected_contextmanager
@scope_injected_contextmanager
def decorated_function(): pass

with decorated_function:
    something = 100

Or as a function

from scope_injected_contextmanager import scope_injected_contextmanager
@scope_injected_contextmanager
def decorated_function(): pass

with decorated_function():
    something = 100

Simple example

from scope_injected_contextmanager import scope_injected_contextmanager

fetch = lambda request: ("ok", 200)

@scope_injected_contextmanager
def log_request(request, response):
    print(f"request: {request} response: {response}")

with log_request:
    request = {
        "query_args": {
            'foo': 10
        }
    }
    response = fetch(request)

# prints
# request: {'query_args': {'foo': 10}} response: ('ok', 200)

Advanced example

from scope_injected_contextmanager import scope_injected_contextmanager

fetch = lambda request: ("ok", 200)

@scope_injected_contextmanager
def log_request(request, response, some_explicit_variable=None):
    print(f"request: {request} response: {response} some_explicit_variable: {some_explicit_variable}")

with log_request(some_explicit_variable="foo):
    request = {
        "query_args": {
            'foo': 10
        }
    }
    response = fetch(request)

# prints
# request: {'query_args': {'foo': 10}} response: ('ok', 200) some_explicit_variable: foo

why?

I needed a low-on-syntax context-manager that would log request_args and response. When looking at implementing it i ran into this issue, and asked for help: "Spooky action observed in Python context manager"

I was let down by the fact that you apparently can't give a context manager access to your variables.

Thats why i hacked this together ;-)

Testing

see tests

run make setup-all tox on a (linux or osx) with pyenv installed.