Signal Handlers

Pokie provides a SignalManager for registering OS signal handlers (e.g. SIGINT, SIGTERM) through the DI container. Multiple handlers can be registered for the same signal, and they are executed in registration order.

SignalManager

The signal manager is available in the DI container as DI_SIGNAL:

from pokie.constants import DI_SIGNAL

mgr = di.get(DI_SIGNAL)

add_handler(signalnum, handler)

Register a handler for a specific signal number.

import signal
from pokie.constants import DI_SIGNAL


def on_shutdown(di, signal_no, stack_frame):
    print(f"Received signal {signal_no}, shutting down...")
    # cleanup resources


mgr = di.get(DI_SIGNAL)
mgr.add_handler(signal.SIGINT, on_shutdown)
mgr.add_handler(signal.SIGTERM, on_shutdown)

Parameters:

Parameter	Type	Description
signalnum	int	OS signal number (e.g. signal.SIGINT)
handler	callable	Handler function

Handler signature:

def handler(di: Di, signal_no: int, stack_frame) -> None

Parameter	Description
di	The DI container
signal_no	The signal number that was received
stack_frame	The current stack frame

Raises:

• TypeError if signalnum is not an integer
• TypeError if handler is not callable

Multiple Handlers

Multiple handlers can be registered for the same signal. They are executed in registration order:

def handler_one(di, signal_no, stack_frame):
    print("First handler")

def handler_two(di, signal_no, stack_frame):
    print("Second handler")

mgr.add_handler(signal.SIGINT, handler_one)
mgr.add_handler(signal.SIGINT, handler_two)
# Both handlers run when SIGINT is received

Error Handling

If a handler raises an exception, the error is logged and execution continues to the next handler. This ensures that one failing handler does not prevent other handlers from running.