This is a context manager to cleanup your environment. Your claenup code will be called even if the program is stopped by Ctrl-C or kill command.
Project description
finalizer
This is a context manager to cleanup your environment. Your claenup code will be called even if the program is stopped by Ctrl-C or kill command.
This is useful for;
- Create a directory in the middle of the process, but you don't want it to remain when the process finished.
- You put temporary data in a database, but you don't want it to remain when the process finished.
- You want to be notified when a program terminates, whether it ends normal or dead.
- Etc...
You can also use for cleanup process for docker container, but be careful for the timeout after docker stop. (Default 10 secs)
Limitation
- This module cannot prevent from kill -9 (SIGKILL).
- Child thread in multi thread cannot handle signal. (multi_process is ok)
Install
pip install finalizer
How to Use
With with
clause
Simple code
from time import sleep
from finalizer import Finalizer
def cleanup1() -> None:
print("cleanup1 start")
sleep(3)
print("cleanup1 end")
def task1() -> None:
print("task1 start")
with Finalizer(cleanup1):
sleep(3)
print("task1 end")
Output:
task1 start
cleanup1 start
cleanup1 end
task1 end
with options
def cleanup2(param1: str, param2: int) -> None:
print("cleanup2 start", param1, param2)
sleep(3)
print("cleanup2 end")
def task2() -> None:
print("task2 start")
with Finalizer(cleanup2, "test", param2=42):
sleep(3)
print("task2 end")
Output:
task2 start
cleanup2 start test 42
cleanup2 end
task2 end
you can nest with
clause
def cleanup3() -> None:
print("cleanup3 start")
sleep(3)
print("cleanup3 end")
def task3() -> None:
print("task3 start")
with Finalizer(cleanup3):
sleep(3)
task1()
sleep(3)
print("task3 end")
Output:
task3 start
task1 start
cleanup1 start
cleanup1 end
task1 end
cleanup3 start
cleanup3 end
task3 end
With decorator
def cleanup4() -> None:
print("cleanup4 start")
sleep(3)
print("cleanup4 end")
@Finalizer(cleanup4)
def task4() -> None:
print("task4 start")
sleep(3)
print("task4 end")
Output:
task4 start
task4 end
cleanup4 start
cleanup4 end
How it works
Even if Ctrl-C is pressed, all cleanup will work.
>>> task3()
task3 start
task1 start <== Press Ctrl-C key here
^Ccleanup1 start
cleanup1 end
cleanup3 start
cleanup3 end
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 5, in task3
File "<stdin>", line 4, in task1
KeyboardInterrupt
Even if Python process is killed, all cleanup will work.
>>> task3()
task3 start
task1 start <== kill python process here
cleanup1 start
cleanup1 end
cleanup3 start
cleanup3 end
While cleanup process is running, Ctrl-C or kill signal does not work.
>>> task3()
task3 start
task1 start <== Press Ctrl-C key here
^Ccleanup1 start <== Press Ctrl-C key here but does not stop
^C^C^Ccleanup1 end
cleanup3 start <== Same here, press Ctrl-C key here many times but does not stop
^C^C^C^C^C^C^C^C^C^C^Ccleanup3 end
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "<stdin>", line 5, in task3
File "<stdin>", line 4, in task1
KeyboardInterrupt
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