Cancel-contexts

This is a simple implementation of cancel-contexts (cancel tokens is C#) in Python. It is inspired by the Go programming language's context package.

• CancelContext is a simple class that can be used to manually cancel.
• TimeoutContext is a simple class that can be used to cancel a context after a certain amount of time.

cancel() - manually cancel the context.

cancelled - a property that returns True if the context is canceled.

bool() - returns True if the context is not canceled or condition is relevant.

check_cancelled() - raises actual BaseCancelContextError if the context is canceled or condition isn't relevant.

Installation

poetry add cancel-contexts

or

pip install cancel-contexts

Usage

from cancel_contexts import CancelContext

ctx = CancelContext()
print(ctx.cancelled) # False
print(bool(ctx)) # True

ctx.cancel()
print(ctx.cancelled) # True
print(bool(ctx)) # False

from cancel_contexts import CancelContext
from cancel_contexts.exceptions import ContextCancelledError

ctx = CancelContext()
counter = 0
while ctx:
    counter += 1
    if counter == 10:
        ctx.cancel()

print(ctx.cancelled) # True

try:
    ctx.check_cancelled()
except ContextCancelledError as e:
    print(e) # Context was cancelled

from time import sleep
from cancel_contexts import TimeOutContext
from cancel_contexts.exceptions import ContextTimeOutError

ctx = TimeOutContext(10)

print(ctx.cancelled) # False

while ctx:
    sleep(1)
    print(ctx.cancelled) # False

print(ctx.cancelled) # True
try:
    ctx.check_cancelled()
except ContextTimeOutError as e:
    print(e) # Context was timed out