I've got the following problem:
I've written a script which is running up to four processes at the same time. Works like a charm when using it via command line.
Then I made the decision to write a GUI with wxPython and I was quickly figuring out that the GUI and the script need to run in different processes so both stay usable while the other is doing something. (i.e. being able to press a stop button while the script is running) This is also working perfectly.
Now the problem:
I just cannot communicate with the GUI while the script is running or at least I have no idea how. I'm trying to write output in a text window by passing "self" (the gui) to the script and in the script I try to do things like "self.outputWindow.WriteText('the script is doing bla 1 of bla 10')"
I even figured out why this won't work: self (the gui object) is not pickable and that's mandatory for multiprocessing, but I don't know how else I should do it.
You can use my tutorial on wxPython and threads, although I'm not sure if Python spreads those threads evenly to all the cores. I suspect it doesn't.
Fortunately, there are examples of using the multiprocessing module with wxPython. See the following links:
http://wiki.wxpython.org/MultiProcessing
wxPython non-blocking GUI threading AND multiprocessing?
wxpython GUI and multiprocessing - how to send data back from the long running process
http://www.blog.pythonlibrary.org/2012/08/03/python-concurrency-porting-from-a-queue-to-multiprocessing/
I hope those are helpful!
Related
I'm trying to speed test my code for a tkinter GUI. Naturally, requiring humans to hit buttons would make speed testing inconsistent. I was thinking that I could just have a timed script run each callback sequentially, but some callbacks like image displays wouldn't be able to run without the GUI open. Now I'm looking for ways to run a script on a GUI that's already in its main loop. Is there a way to do this?
Python has a few modules for handling GUI automation but here is a pretty nice tutorial https://automatetheboringstuff.com/chapter18/.
Also with windows you should be able to simulate keystrokes and mouse movements using the win32 api https://sourceforge.net/projects/pywin32/.
my software uses the subprocess.call([sys.executable, SCRIPT_NAME] instruction in order to open others kind of scripts specified by the user using a GUI (Tkinter). I have two issue with this instruction:
the "command line" scripts start and close themeselves quicly and it means that the user can't interact with them. it's a weird behaviour because in all of them there is an input instruction, so they should wait an input by the user before to close themeselves. how can I solve this issue?
the "GUI" scripts instead, start without any kind of issue, but their "life", let me say, put in stuck the main script (it uses Tkinter). in this case I can interact with the second script but not with the main one. how can I call my other scripts with the subprocess.call() function whithout put in stuck the main one? from my point of view this issue happens because the second script is a part of the same process of the main one and in this case Tkinter has to wait. if we open the others scripts using different processes for all of them the main script would be free to live its life independently of the others. but how can I do it?
I am very much concerned about my productivity all the time. I have recently come across this beautiful chrome extension Limitless
But this is only measuring what i'm doing within the chrome application. As I work most of the time with pdfs, videos etc, I want to develop similar application for linux(ubuntu) desktop enviroment.
Basically I want the script to run continuously as long as the workstation is on.
It should be able to know what I'm currently looking at (for eg a pdf file or a lecture video in vlc) and get the name of the respective file, start time, end times etc and finally post to db.
It is better if it could know if the system is idle or at sleep.
I don't have slightest clue at bash scripting. so my questions is could this task be accomplished with python.
What I've tried?
I started with a search in google "get current application python", "current window title python" etc etc and really surprised to see absurd results.
Please give me pointers on this.
I think you are asking for vocabulary. So I give you what I know.
You are using Ubuntu so your Window Manager may be Gnome.
The window manager knows which window has the focus.
So maybe you want to find out which window has the focus and you want to map it to the Process that opened the window.
What you need to focus on is is module for Python or a Python Binding for the window manager. This module is likely to also be able to control the windows.
The window manager is started with startx.
You could try to call a command line tool and catch the results
How do get the process list on command line:
https://stackoverflow.com/questions/53489/how-do-you-list-all-processes-on-the-command-line-in-windows
And how to call a tool with python:
Python subprocess.call and subprocess.Popen stdout
[edit] Repeating the call in Intervals and counting the intervals a process were running gives you a good estimation of running time of a process...
[edit2] As GreenAsJade said, you search a way to find out which windows has the focus.
See How do I detect the currently focused application?
I've seen a lot of stuff about running code in subprocesses or threads, and using the multiprocessing and threading modules it's been really easy. However, doing this in a GUI adds an extra layer of complication.
From what I understand, the GUI classes don't like it if you try and manipulate them from multiple threads (or processes). The workaround is to send the data from whatever thread you created it in to the thread responsible for the graphics and then render it there.
Unfortunately, for the scenario I have in mind this is not an option: The gui I've created allows users to write their own plotting code which is then executed. This means I have no control over how they plot exactly, nor do I want to have it. (Update: these plots are displayed in separate windows and don't need to be embedded anywhere in the main GUI. What I want is for them to exist separated from the main GUI, without sharing any of the underlying stack of graphics libraries.)
So what I'm wondering now is
Is there some clean(ish) way of executing a string of python code in a whole new interpreter instance with its own ties to the windowing system?
In response to the comments:
The current application is set up as follows: A simple python script loads a wxPython gui (a wx.App). Using this gui users can set up a simulation, part of which involves creating a script in plain python that runs the simulation and post-processes the results (which usually involves making plots and displaying them). At the moment I'm doing this by simply calling exec() on the script code. This works fine, but the gui freezes while the simulation is running. I've experimented with running the embedded script in a subprocess, which also works fine, right up until you try to display the created graphs (usually using matplotlib's show()). At this point some library deep down in the stack of wxPython, wx, gtk etc starts complaining because you cannot manipulate it from multiple threads.
The set-up I would like to have is roughly the same, but instead of the embedded script sharing a GUI with the main application, I would like it to show graphics in an environment of its own.
And just to clarify:
This is not a question about "how do I do multithreading/multiprocessing" or even "how do I do multithreading/multiprocessing within a single wxpython gui". The question is how I can start a script from a gui that loads an entirely new gui. How do I get the window manager to see this script as an entirely separate application?
The easiest way would be to generate it in a temporary folder somewhere and then make a non-blocking call to the python interpreter, but this makes communication more difficult and it'd be quite hard to know when I could delete the temp files again. I was hoping there was a cleaner, dynamical way of doing this.
Can you simply use subprocess to run 'python.exe' and pipe the script in?
Alternatively, the multiprocessing package should suffice if you want to move some (pickle-able) data over to the new process in which you run the script. Just create a function/callable that runs the script, and create a Process object with the callable as target. That way, you should be able to pass some data over, without having GUI issues.
Capturing text with either is easy, subprocess allows that and no more. With multiprocess, you can pass python objects back and forth more easily.
On Windows, you can create window with a parent window from another process, and draw to that.
See the hWndParent argument to CreateWindowEx.
If wxWindows supports getting/setting that explicitly, then you should be good to go.
Depending on your platform, something similar might be possible in any windows system.
So, just giving your users the ability to find the handle of your apps window should give them the option to plot away at views embedded in your app, while running in their own processes.
I don't no much about wx, I work with jython(python implemented in java and you can use java) and swing. Swing has its own worker thread, and if you do gui updates you wrap your code into a runnable and invoke it with swing.invokelater.
You could see if wx has something like that, if you however are only allowed to manipulate the gui from the thread in which you created it try something similar. create a proxy object for your gui, which forwards all your calls to your thread which forwards them to the gui.
But proxying like this gets messy. how about you let them define classes, with an 'updateGui' function, that they should hand back to you over a queue and that you will execute in your gui thread.
In wxPython land when you use threads, you have to use its thread-safe methods to communicate with the GUI: wx.CallAfter, wx.CallLater or wx.PostEvent. In your case, I would run any long running code in a separate thread/process and when it's done its processing, send the result to the GUI. The GUI can instantiate a new frame and use matplotlib or PyPlot to show the plot, depending on which way you want to go. I've heard you can draw the plot using FloatCanvas too.
Anyway, if you instantiate the new frame correctly, then you can instantiate N frames and show them and be fine. See the wxPython wiki for a few examples of using Threads with wx: http://wiki.wxpython.org/LongRunningTasks
I'd like to know how to have a program wait for another program to finish a task. I'm not sure what I'd look for for that...
Also, I'm using a mac.
I'd like to use Python or perhaps even applescript (I could just osascript python if the solution if for applescript anyway)
Basically this program "MPEGstreamclip" converts videos, and it opens what appears to be 2 new windows while it's converting. One window is a conversion progress bar, and the other window is a preview of the conversion. (Not sure if these actually count as windows)
(Also, MPEGstreamclip does not have an applescript dictionary, so as far as I know, it can't listen for certain window names existence)
But basically I want my program to listen for when MPEGstreamclip is done, and then run its tasks.
If it helps, when the conversion is done, the mpegstreamclip icon in the dock bounces once. I'm not sure what that means but I'd think you could use that to trigger something couldn't you?
Thanks!
I realized GUI applescript was the answer in this scenario. With it I could tell the PROCESS to get every window, and that worked. However, I'm leaving this up because I'd like to know other ways. I'm sure this GUI workaround won't work for everything.
If the MPEGstreamclip actually ends when it is done, you could wrap the whole thing up in a python script using various techniques already discussed in another post. Just be sure to wait for the external process to end before continuing with your other steps.