PeaceFounder.Schedulers

mutable struct Scheduler
    condition::Condition
    pool_interval::Union{Int, Nothing}
    retry_interval::Union{Int, Nothing}
    delay::Int
    started::Bool
    finished::Bool
    schedule::Vector{Tuple{DateTime, <:Any}}
end

Represents a waitable object which resumes at predetermined scheduled times. A typical use for it is in the event loop like:

scheduler = Scheduler(; retry_interval = 1)

lock(scheduler) do 
    schedule!(scheduler, now() + Second(1), value)
end

while true
    value = wait(scheduler)
    try
        # Do some stuff
    catch
        retry!(scheduler)
    end
end

In the event loop one manages a state machine which can succed and fail. If it succeds a scheduled time is taken out from the scheduler and proceeds waiting the next event. In the case event at scheduled time had failed the scheduler is notified with retry! method and attempts to run the event loop againafter retry_interval until succeeds.

lock(scheduler::Scheduler)

Lock a scheduler. This is necessary to avoid simultanous modifications of the schedule field. Note that other Scheduler fields are not protected with the lock as thoose are considered internal.

notify(scheduler::Scheduler[, value])

Notify a scheduler with a value which is returned at wait.

wait(scheduler::Scheduler)

Wait until next event is reached and return it's value. In the case event have run through smoothelly the scheduler event is droped with the next wait call. See also retry! method.

next_event(scheduler::Scheduler)

Return the next event in seconds and coresponding event value. Return nothing if no events are scheduled.

retry!(scheduler::Scheduler)

Notifies the scheduler that event have run unsucesfully which reschedules it after specified retry_time(See Scheduler).

schedule!(scheduler::Scheduler, timestamp::DateTime[, value])

Schedule an event at timestamp with a provided value. To avoid messing up a schedule acquire a scheduler's lock before adding the event as:

lock(scheduler) do
    schedule!(scheduler, now() + Second(1), value)
end

waituntil(time::DateTime)

Waits until given time is reached.