Helper

Module for various helper classes and functions.

This module provides utility functions and classes that assist with system operations such as checking time synchronization and handling graceful termination of processes. The functionality is tailored to Unix-based systems.

Usage

The primary components of this module are: - check_time_sync: A function that checks whether the system's clock is synchronized. - GracefulKiller: A class that allows for graceful termination of a running application upon receiving interrupt signals (e.g., SIGINT, SIGTERM).

Examples:

Using GracefulKiller to handle termination signals:

>>> killer = GracefulKiller()
>>> while not killer.kill_now:
>>>     # Perform long-running task
>>>     pass
>>> print("Application terminated gracefully.")

Classes:

Name	Description
GracefulKiller	Handles system signals for graceful application termination.

Functions:

Name	Description
check_time_sync	Checks if the system clock and RTC are synchronized.

Notes

• This module is intended for use on Unix-based systems.

GracefulKiller

Handles system signals for graceful application termination.

GracefulKiller listens for interrupt signals (e.g., SIGINT, SIGTERM) and sets a flag when such a signal is received, allowing the application to terminate gracefully.

Attributes:

Name	Type	Description
kill_now	bool	A flag indicating whether a termination signal has been received.

Methods:

Name	Description
exit_gracefully	Signal handler that sets the kill_now flag to True.

Examples:

>>> killer = GracefulKiller()
>>> while not killer.kill_now:
>>>     # Perform long-running task
>>>     pass
>>> print("Application terminated gracefully.")

__init__()

Initialize the GracefulKiller instance and set up signal handlers.

Registers the signal handlers for SIGINT and SIGTERM, which trigger the exit_gracefully method to handle termination signals.

exit_gracefully(signum, frame)

Handle termination signals and set the kill flag.

This method is called when a registered signal (SIGINT or SIGTERM) is received. It sets the kill_now attribute to True, indicating that the application should terminate.

Parameters:

Name	Type	Description	Default
signum	int	The signal number received.	required
frame	any	The current stack frame (unused in this method).	required

Notes

This method is intended to be used as a signal handler and is not typically called directly.

check_time_sync(sync_status)

Check if the system clock and RTC are synchronized.

This function uses the timedatectl command to check whether the system clock is synchronized and if the RTC (Real-Time Clock) is set. The results are stored in the provided sync_status list.

Parameters:

Name	Type	Description	Default
sync_status	list	A list to store the synchronization status. The first element is set to True if either the system clock or RTC is synchronized, False if neither is synchronized, and None if an error occurred.	required

Examples:

>>> sync_status = [False]
>>> check_time_sync(sync_status)
>>> print(sync_status[0])
True  # If the system is synchronized