Easy Timers

To use:

from XPPython3.utils import timers

X-Plane SDK uses flight loop callbacks to schedule events in the future. Xlua provides an simple wrapper which defines some easy-to-use timers. XPPython3 also supports this interface. (This module can be used with or without other python-xlua inspired modules).

Timers are keyed by their callback function: any particular function can have only one timer active at a time, though that timer may repeat, and you are permitted an unlimited number of timers.

The callback function, executed on timer expiration requires no parameters and should not return any value. As it is executed within a flightloop, it should be quick so as to not delay the sim:

>>> def timer_callback():
...    print(f"Current flight time is {xlua.FLIGHT_TIME}")
...

As with other callbacks within XPPython3, if your timer callback is a method of PythonInterface, it should have the self parameter, which will be available within you callback. For example:

class PythonInterface(EasyPython):
    def __init__(self):
        super().__init__()
        self.name = "foobar"

    def timer_callback(self):
        print(f"Flight time is {xlua.FLIGHT_TIME} in plugin {self.name}")

    def onStart(self):
        timers.run_after_time(self.timer_callback, 10)

To start a timer, use:

To query if a timer is active use:

Repeating timers, and timers on a delay can be stopped using:

Note that timers are paused while the simulator is paused, and they will run faster if the sim flight model is executing faster (e.g., command sim/operation/flightmodel_speed_change or dataref sim/time/sim_speed). Change in ground-speed multiplier does not change timer execution.

Functions

run_after_time(func, delay)
Parameters

  • Callable (func) – function to be run

  • float (delay) – Number of seconds to wait prior to execution. Run once.

Returns

None

Run function once after delay seconds. This does not return any value. You can stop this timer prior to execution if required by passing the same callback func to stop_timer():

>>> def deferred_flight_start():
...   print('Deferred flight start')
...   interior_lites_0.value = .4
...   interior_lites_1.value = 1
...   interior_lites_2.value = 1
...   interior_lites_3.value = 0.2
...   panel_glareshield_brightness.value = 0.3
...
>>> run_after_time(deferred_flight_start, .1)

This is implemented as run_timer(func, delay, 0).

run_at_interval(func, interval)
Parameters

  • Callable (func) – function to be run

  • float (interval) – Number of seconds to wait prior to execution, and repeat at interval.

Returns

None

Run function until stopped, after each interval seconds. The first execution of the call back is after the initial interval. To have the first execution different from the interval, use run_timer(). This does not return any value. You can stop this timer by passing the same callback func to stop_timer():

>>> def func():
...    print("Hello World")
...
>>> run_at_interval(func, 5)
Hello World
Hello World
>>> is_timer_scheduled(func)
True
>>> stop_timer(func)

This is implemented as run_timer(func, interval, interval).

run_timer(func, delay, interval)
Parameters

  • Callable (func) – function to be run

  • float (interval) – Number of seconds to wait prior to first execution.

  • float – Number of seconds, after delay, to repeat at interval.

Returns

None

Run function until stopped. First execution is after delay seconds (which may be 0), and each subsequent execution is after interval seconds. It does not return any value. You can stop this timer by passing the same callback func to stop_timer():

>>> run_timer(func, 0, 5)
Hello World
Hello World
>>> is_timer_scheduled(func)
True
>>> stop_timer(func)
is_timer_scheduled(func)
Parameters

Callable (func) – function to stop

Returns

Boolean, True if given callback function is scheduled.

Returns True if given callback function is scheduled as a one-time or repeating timer. If timer has already executed (and is not repeating), stopped, or never scheduled, returns False.

stop_timer(func)
Parameters

Callable (func) – function to stop

Returns

None

Stops timer with given callback. No error if timer is not found.