I can't find the answer to an interesting moment.
in akka.net I have the scheduler. It will work in actor which are sort out a number.
here a simple implementation
_statusScheduler = Context.System.Scheduler.ScheduleTellRepeatedlyCancelable(
TimeSpan.FromSeconds(_shedulerInterval),
TimeSpan.FromSeconds(_shedulerInterval),
_reporterActor,
new ProgressReport(requestId, _testedQuantity),
Self);
where
_shedulerInterval - 5-second interval,
_testedQuantity - quantity of tested number all time updated.
and after 5 seconds it is sent 0; always, not a changed number. And here is a question: is it possible to send updated quantity?
I can't send the message to the updating quantity from Recieve<> methods, because my actor is handled the counting message and it is counted the quantity all the time and updated it(when it finished it will receive next message). But all five seconds I should generate a report by a scheduler. Is it possible to fix it?
I think now I need to send all logic because it works fine, and the stone of my problem is scheduler behavior.
The issue you have here is that the message you pass into the scheduler, new ProgressReport(requestId, _testedQuantity), is what is going to be sent each time. Since you're passing in those integer values by value, the object is going to have the original values for those fields at the time you created the message and therefore the message will never update.
If you want to be able to change the content that is sent in the recurring scheduler, do this instead:
var self = Self; // need a closure here, since ActorContext won't be available
_statusScheduler = Context.System.Scheduler.Advanced.ScheduleRepeatedlyCancelable(interval, interval, () => {
_reporterActor.Tell(new ProgressReport(requestId, _testedQuantity), self);
});
This usage of the scheduler will generate a new message each time when it invokes the lambda function and thus you'll be able to include the updated integer values inside your object.
Related
I use ordered set to true, however when many (1000 or more) messages are sent in a short period of time (< 1 second) the messages received are not all received in the same order.
rtcPeerConnection.createDataChannel("app", {
ordered: true,
maxPacketLifeTime: 3000
});
I could provide a minimal example to reproduce this strange behavior if necessary.
I also use bufferedAmountLowThreshold and the associated event to delay when the send buffered amount is too big. I chose 2000 but I don't know what the optimal number is. The reason I have so many messages in a short period of time is because I don't want to overflow the maximum amount of data sent at once. So I split the data into 800 Bytes packs and send those. Again I don't know what the maximum size 1 message can be.
const SEND_BUFFERED_AMOUNT_LOW_THRESHOLD = 2000; //Bytes
rtcSendDataChannel.bufferedAmountLowThreshold = SEND_BUFFERED_AMOUNT_LOW_THRESHOLD;
const MAX_MESSAGE_SIZE = 800;
Everything works fine for small data that is not split into too many messages. The error occurs randomly for big files only.
In 2016/11/01 , there is a bug that lets the dataChannel.bufferedAmount value change during the event loop task execution. Relying on this value can thus cause unexpected results. It is possible to manually cache dataChannel.bufferedAmount, and to use that to prevent this issue.
See https://bugs.chromium.org/p/webrtc/issues/detail?id=6628
We are designing a system that will stream event using RabbitMQ (maybe later kafka) and spark streaming. Some or our events have been broken to several event types, so not to have too big of an event. This means that certain events have to wait for the other events (with the same id). We cannot proceed with processing until all events for a specific event have arrived.
Is there a way to delay the processing of an event until the next processing window in spark streaming (if the other event has not arrived)
Thank
Nir
From an architectural perspective, there are questions to consider:
how do you determine that all events have arrived?
what happens if one event gets lost?
what happens if events arrive out of order? Last first and similar?
In principle it would seem that breaking down an event in parts that was originally formed as a whole would increase the complexity and affect the reliability of the system.
To answer to the question in any case, since Spark 1.6.x a new stateful streaming function has been introduced: mapWithState. mapWithState allows you to keep state information per key and issue zero or more events of the same or different type in response to an incoming event.
Applied to this case, we could think of modelling the state as State[PartialEvent]: as events come in, they are assembled in a PartialEvent object. Once the criteria that an event is complete has been fulfilled, mapWithState can generate a WholeEvent object to be processed downstream.
The process would roughly(*) look like this:
val sourceEventDStream:DStream[Event] = ???
def stateUpdateFunction(eventId:String, event: Event, partialEventState: State[PartialEvent]): Option[WholeEvent] = {
val eventState = partialEventState.get() // Get current state of the event
val updatedEvent = merge(eventState, event)
if (updatedEvent.isComplete) {
partialEventState.remove()
Some(WholeEvent(updatedEvent))
} else {
partialEventState.update(updatedEvent)
None
}
}
val wholeEventDStream:DStream[WholeEvent] = sourceEventDStream.mapWithState(StateSpec.function(stateUpdateFunction))
//do stuff with wholeEventDStream ...
As you could observe, with this approach, any PartialEvent that never completes will stay in the state forever. We also need a unique key to identify events that belong together. There're timeout options that must be considered to cover for the failure cases, but the bottom line is that preserving a whole event through the pipeline would be a better approach, if technically possible.
(*) not compiled or tested. Provided only to illustrate the idea.
I'm new to psychopy and python. I'm trying to program a way to quit a script (that I didn't write), by pressing a key for example. I've added this to the while loop:
while n < total
start=time.clock()
if len(event.getKeys()) > 0:
break
# Another while loop here that ends when time is past a certain duration after 'start'.
And it's not working, it doesn't register any key presses. So I'm guessing key presses are only registered during specific times. What are those times? What is required to register key presses? That loop is extremely fast, sending signals every few milliseconds, so I can't just add wait commands in the loop.
If I could just have a parallel thread checking for a key press that would be good too, but that sounds complicated to learn.
Thanks!
Edits: The code runs as expected otherwise (in particular no errors). "core" and "event" are included. There aren't any other "event" command of any kind that would affect the "key press log".
Changing the rest of the loop content to something that includes core.wait statements makes it work. So for anybody else having this difficulty, my original guess was correct: key presses are not registered during busy times (i.e. in my case a while statement that constantly checks the time), or possibly only during specific busy times... Perhaps someone with more knowledge can clarify.
....So I'm guessing key presses are only registered during specific
times. What are those times? What is required to register key
presses?....
To try and answer your specific question, the psychopy api functions/methods that cause keyboard events to be registered are ( now updated to be literally every psychopy 1.81 API function to do this):
event.waitKeys()[1]
event.clearEvents()[1]
event.getKeys()[2]
event.Mouse.getPressed()
win.flip()
core.wait()
visual.Window.dispatchAllWindowEvents()
1: These functions also remove all existing keyboard events from the event list. This means that any future call to a function like getKeys() will only return a keyboard event if it occurred after the last time one of these functions was called.
2: If keyList=None, does the same as *, else removes keys from the key event list that are within the keyList kwarg.
Note that one of the times keyboard events are 'dispatched' is in the event.getKeys() call itself. By default, this function also removes any existing key events.
So, without being seeing the full source of the inner loop that you mention, it seems highly likely that the event.getKeys() is never returning a key event because key events are being consumed by some other call within the inner loop. So the chance that an event is in the key list when the outer getKeys() is called is very very low.
Update in response to OP's comment on Jonas' test script ( I do not have enough rep to add comments to answers yet):
... Strange that you say this ..[jonas example code].. works
and from Sol's answer it would seem it shouldn't. – zorgkang
Perhaps my answer is giving the wrong understanding, as it is intended to provide information that shows exactly why Jonas' example should, and does, work. Jonas' example code works because the only time key events are being removed from the event buffer is when getKeys() is called, and any events that are removed are also returned by the function, causing the loop to break.
This is not really an answer. Here's an attempt to minimally reproduce the error. If the window closes on keypress, it's a success. It works for me, so I failed to reproduce it. Does it work for you?
from psychopy import event, visual, core
win = visual.Window()
clock = core.Clock()
while True:
clock.reset()
if event.getKeys():
break
while clock.getTime() < 1:
pass
I don't have the time module installed, so I used psychopy.core.Clock() instead but it shouldn't make a difference, unless your time-code ends up in an infinite loop, thus only running event.getKeys() once after a few microseconds.
Is this possible?
I have a file in which a movie clip is launched when the user roles over another element. To make the user experience more pleasant this happens after a 3 second delay using setInterval. Is there a way of stopping and resetting this time if the user rolls off the element before the 3 seconds is up?
var xTimer = setInterval(wait, 3000);
function wait(){
show('all');
play('all');
clearInterval(xTimer);
}
Above is the code I have used to set the delay, and below is the code I had assumed would interrupt and reset the timer.
invisBtn.onRollOut = function(){
rollover_mc.gotoAndStop(1);
stop();
clearInterval(xTimer());
trace('off');
}
Any help on this would be massively appreciated.
First, the setInterval & clearInterval functions use a Number variable to work.
setInterval() returns a Number variable, and clearInterval() takes that Number in parameter to remove the previous started interval. Here you seem to keep the interval ID inside a function variable instead of a Number one.
Thus, clearInterval(xTimer()); should in reality be clearInterval(xTimer); (without the parenthesis after xTimer).
And secondly, so you can use it in the invisBtn.onRollOut function, just be sure that the xTimer variable is scoped correctly (not inside a function where the invisBtn.onRollOut isn't also), and not on different keyframes of the timeline (timeline keyframes in Flash tends to forget the code you've written on it as soon as the reading head passes onto a new keyframe of the layer which has the code on it).
Feel free to ask more details if you need !
I have recorded real-time stock quotes in an SQL database with fields Id, Last, and TimeStamp. Last being the current stock price (as a double), and TimeStamp is the DateTime when the price change was recorded.
I would like to replay this stream in the same way it came in, meaning if a price change was originally 12 seconds apart then the price change event firing (or something similar) should be 12 seconds apart.
In C# I might create a collection, sort it by the DateTime then fire an event using the difference in time to know when to fire off the next price change. I realize F# has a whole lot of cool new stuff relating to events, but I don't know how I would even begin this in F#. Any thoughts/code snippets/helpful links on how I might proceed with this?
I think you'll love the F# solution :-).
To keep the example simple, I'm storing the price and timestamps in a list containing tuples (the first element is the delay from the last update an the second element is the price). It shouldn't be too difficult to turn your input data into this format. For example:
let prices = [ (0, 10.0); (1000, 10.5); (500, 9.5); (2500, 8.5) ]
Now we can create a new event that will be used to replay the process. After creating it, we immediatelly attach some handler that will print the price updates:
let evt = new Event<float>()
evt.Publish.Add(printfn "Price updated: %f")
The last step is to implement the replay - this can be done using asynchronous workflow that loops over the values, asynchronously waits for the specified time and then triggers the event:
async { for delay, price in prices do
do! Async.Sleep(delay)
evt.Trigger(price) }
|> Async.StartImmediate
I'm starting the workflow using StartImmediate which means that it will run on the current thread (the waiting is asynchronous, so it doesn't block the thread). Keeping everything single-threaded makes it a bit simpler (e.g. you can safely access GUI controls).
EDIT To wrap the functionality in some component that could be used from other parts of the application, you could define a type like this:
type ReplyDataStream(prices) =
let evt = new Event<float>()
member x.Reply() =
// Start the asynchronous workflow here
member x.PriceChanged =
evt.Publish
The users can then create an instance of the type, attach their event handlers using stream.PriceChanged.Add(...) and then start the replaying the recorded changes using Reply()