Cron Jobs

JAXLClock maintains a global clock which is updated after every iteration of the main select loop. During the clock tick phase, JAXLClock also dispatches any scheduled cron jobs.

Lets try some cron job scheduling using Jaxl interactive shell:

>>> ./jaxlctl shell
jaxl 1>
jaxl 1> function do_job($params) {
.......     echo "cron job called";
....... }
jaxl 2>
jaxl 2> $ref = JAXLLoop::$clock->call_fun_after(
.......     4000,
.......     'do_job',
.......     'some_parameters'
....... );
jaxl 3> echo $ref;
jaxl 4>
cron job called
jaxl 5> quit

We just saw a live example of a cron job. Using JAXLClock::call_fun_after/3 we were able to call our do_job function after 4000 microseconds.


Since cron jobs are called inside main select loop, do not execute long running cron jobs using JAXLClock else the main select loop will not be able to detect any new activity on watched file descriptors. In short, these cron job callbacks are blocking.

In future, cron jobs might get executed in a seperate process space, overcoming the above limitation. Until then know what your jobs are doing and for how long or execute them in a seperate process space yourself. You have been warned !!!

one time jobs

call_fun_after($time, $callback, $args)

schedules $callback with $args after $time microseconds

periodic jobs

call_fun_periodic($time, $callback, $args)

schedules periodic $callback with $args after $time microseconds

cancel a job


cancels a previously scheduled $callback

detecting bottlenecks

tc($callback, $args)

calculate execution time of a $callback with $args