I think this tests the capability of computers as two processes cannot be run at the same time. I am a beginner at python, and I was wondering if there any ways which someone can stop a countdown when a user inputs something. Not using Ctrl+C, as well as keeping the countdown running.
I have been trying to make a Quiz bot, adding a timer and then stopping the timer when the user inputs an answer for the question.
Related
I'm writing a game in Rust where each player can submit some python scripts to the server in order to automate various tasks in the game. I plan on using pyo3 to run the python from rust.
However, I can see an issue arising if a player submits a script like this:
def on_event(e):
while True:
pass
Now when the server calls the function (using something like PyAny::call1()) the thread will hang as it reaches the infinite loop.
My first thought was to have pyo3 execute the python one statement at a time, therefore being able to exit if the script been running for over a certain threshold, but I don't think pyo3 supports this.
My next idea was to give each player their own thread to run their own scripts on, that way if one of their scripts got stuck it only affected their gameplay. However, I still have the issue of not being able to kill a thread when it gets stuck in an infinite loop - if a lot of players submitted scripts that just looped, lots of threads would start using a lot of CPU time.
All I need is way to execute python scripts in a way such that if one of them does loop, it does not affect the server's performance at all.
Thanks :)
One solution is to restrict the time that you give each user script to run.
You can do it via PyThreadState_SetAsyncExc, see here for some code. It uses C calls of the interpreter, which you probably can access in Rust (with PyO3 FFI magic).
Another way would be to do it on the OS level: if you spawn a process for the user script, and then kill it when it runs for too long. This might be more secure if you limit what a process can access (with some OS calls), but requires some boilerplate to communicate between the host.
I got a question for you guys and its not as specific as usual, which could make it a little annoying to answer.
The tool i'm working with is Camunda in combination with Groovy scripts and the goal is to reduce the maximum cpu load (or peak load). I'm doing this by "stretching" the work load over a certain time frame since the platform seems to be unhappy with huge work load inputs in a short amount of time. The resulting problem is that Camunda wont react smoothly when someone tries to operate it at the UI - Level.
So i wrote a small script which basically just lets each individual process determine his own "time to sleep" before running, if a certain threshold is exceeded. This is based on how many processes are trying to run at the same time as the individual process.
It looks like:
Process wants to start -> Process asks how many other processes are running ->
waitingTime = numberOfProcesses * timeToSleep * iterationOfMeasures
CPU-Usage Curve 1,3 without the Script. Curve 2,4 With the script
Testing it i saw that i could stretch the work load and smoothe out the UI - Levels. But now i need to describe why this is working exactly.
The Questions are:
What does a sleep method do exactly ?
What does the sleep method do on CPU - Level?
How does an OS-Scheduler react to a Sleep Method?
Namely: Does the scheduler reschedule or just simply "wait" for the time given?
How can i recreate and test the question given above?
The main goal is not for you to answer this, but could you give me a hint for finding the right Literature to answer these questions? Maybe you remember a book which helped you understand this kind of things or a Professor recommended something to you. (Mine wont answer, and i cant blame him)
I'm grateful for hints and or recommendations !
i'm sure you could use timer event
https://docs.camunda.org/manual/7.15/reference/bpmn20/events/timer-events/
it allows to postpone next task trigger for some time defined by expression.
about sleep in java/groovy: https://www.javamex.com/tutorials/threads/sleep.shtml
using sleep is blocking current thread in groovy/java/camunda.
so instead of doing something effective it's just blocked.
I know there are some questions about this topic but none of these helped me to find a solution.
I've got two Timeline Animations, I want to execute them after a delay of a few seconds. I'm gonna show you an example:
Every time I click my mouse, the Animation shall reset to its default delay time, let's say 5 seconds. If I'll do nothing the time's running away until it's zero. And when I reach the 0 seconds, the Animation has to start(). And so on.
Of course Thread.sleep() would make my UI freeze until the mission is done.
And I don't know whether I should use Thread, Task or other classes because the work is not that complex.
There are a bunch of ways to do it, but I'm not experienced in multithreading and I wanna learn to make it efficiently. Thank you guys a lot.
You can probably achieve what you want using
timeline.setDelay(...);
to specify a delay before the timeline starts,
timeline.setCycleCount(Animation.INDEFINITE);
to make it repeat indefinitely, and
timeline.playFromStart();
to make it start again from the beginning (after its specified delay).
I am new to wxPython, so please be gentle. I am trying to make a game using wxPython. I need to be able to handle events (button clicks) while the game is in progress.
The process is:
Deal the cards
Wait for user input
Continue accordingly
The way I have implemented it is:
app = wx.App()
g = Game() # calls g.Play() which executes the process above
app.Mainloop()
However the application freezes. I think the problem relates to being unable to respond to events while the process is being executed. How can I get around this?
I had a look at threading, but cannot see how to make this work in my case. If I create a new thread to deal with user inputs from within Game(), that will not be able to update the values in Game().
I am sure there is a "correct" way of doing this which I don't know because I am unfamiliar with wxPython. Can anyone help?
Yo do not need a seperate function play() to run the game. Just set up the event handlers to compute the state of the game during every event which results in a move of the game.
A good option would be to define a game state as say the cards in each players hands, and the turns that have been played and the scores, all defined as an object of a state class.
Chalk out an outline of how your game's architecture first. And you might also want to take a look at some examples and documentations on wxPython if you are new to it.
wxPython (and all GUI toolkits) are event driven. What this means is that they all wait for the user to "do something", like press a button, move the mouse, press a key on the keyboard, etc. When the uses does one of these things, wxPython checks to see if any of those events are bound to an event handler. If they aren't, wx will usually ignore the events.
You can learn about how to bind events properly here:
http://wiki.wxpython.org/self.Bind%20vs.%20self.button.Bind
So when you start the program, it should probably deal the cards at the start or possibly prompt the user to see if they want to start a new game or possibly continue a game. After that, the application would wait for the user to "do something". If the user executes a process that takes a long period of time (like a complex calculation, downloading a large file, etc), that process should be put into a thread. If you don't put it into a thread, then that process will block the UI's main loop and your app will freeze. See the following articles for information about wxPython and threads:
http://wiki.wxpython.org/LongRunningTasks
http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/
I hope these links help you on your way.
The program I am developing uses threads to deal with long running processes. I want to be able to use Gauge Pulse to show the user that whilst a long running thread is in progress, something is actually taking place. Otherwise visually nothing will happen for quite some time when processing large files & the user might think that the program is doing nothing.
I have placed a guage within the status bar of the program. My problem is this. I am having problems when trying to call gauge pulse, no matter where I place the code it either runs to fast then halts, or runs at the correct speed for a few seconds then halts.
I've tried placing the one line of code below into the thread itself. I have also tried create another thread from within the long running process thread to call the code below. I still get the same sort of problems.
I do not think that I could use wx.CallAfter as this would defeat the point. Pulse needs to be called whilst process is running, not after the fact. Also tried usin time.sleep(2) which is also not good as it slows the process down, which is something I want to avoid. Even when using time.sleep(2) I still had the same problems.
Any help would be massively appreciated!
progress_bar.Pulse()
You will need to find someway to send update requests to the main GUI from your thread during the long running process. For example, if you were downloading a very large file using a thread, you would download it in chunks and after each chunk is complete, you would send an update to the GUI.
If you are running something that doesn't really allow chunks, such as creating a large PDF with fop, then I suppose you could use a wx.Timer() that just tells the gauge to pulse every so often. Then when the thread finishes, it would send a message to stop the timer object from updating the gauge.
The former is best for showing progress while the latter works if you just want to show the user that your app is doing something. See also
http://wiki.wxpython.org/LongRunningTasks
http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/
http://www.blog.pythonlibrary.org/2013/09/04/wxpython-how-to-update-a-progress-bar-from-a-thread/