there may very well be an answer to this question, but it's really hard to google for.
you can add commands to gdb by writing them in python. I am interested in debugging one of those python scripts that's running in gdb session.
my best guess is to run gdb on gdb and execute the user added command and somehow magically break on the python program code?
has anybody done anything like this before? I don't know the mechanism by which gdb calls python code, so if it's not in the same process space as the gdb that's calling it, I don't see how I'd be able to set breakpoints in the python program.
or do I somehow get pdb to run in gdb? I guess I can put pdb.set_trace() in the python program, but here's the extra catch: I'd like to be able to do all this from vscode.
so I guess my question is: what order of what things do I need to run to be able to vscode debug a python script that was initiated by gdb?
anybody have any idea?
thanks.
so I figured it out. it's kinda neat.
you run gdb to debug your program as normal, then in another window you attach to a running python program.
in this case the running python program is the gdb process.
once you attach, you can set breakpoints in the python program, and then when you run commands in the first window where the gdb session is, if it hits a breakpoint in the python code, it will pop up in the second window.
the tipoff was that when you run gdb there does not appear to be any other python process that's a child of gdb or related anywhere, so I figured gdb must dynamically link to some python library so that the python compiler/interpreter must be running in the gdb process space, so I figured I'd try attaching to that, and it worked.
Related
I often use the python breakpoint() command as a way of debugging code or for changing the values of variable on-the-fly. This works great when I launch a python script from the (windows) console, as breakpoint() lets me type commands in that console.
My question is how do I do achieve something similar when running a python script launched some other way? For example, when I package my code into an .exe with PyInstaller (with the no-console option to keep it tidy) and launch the .exe, breakpoint() does nothing at all. I know one way to remove this problem is to compile the .exe without the no-console option, but I'd rather have it there as it just keeps everything clean. A similar problem also arises when running a python script via a os.execl() call in another.
Is there someway of making the code launch its own console whenever breakpoint() is called, and having that console control the debugging commands? I suspect that this is possible through manipulating the PYTHONBREAKPOINT variable, but I don't know how, or where to start looking.
I have the situation that I want the job done from eclipse so I use eclipse's .launch configuration. I tried to make it run python directly but got error: error 193 (%1 is not a valid Win32 app). where %1 is probably my python script.
I decided to create a simple batch script that calls this big wild python animal.
I did a lot of combinations and found this the best (batch outputs some strings, runs python, waits for it, the outputs some strings again):
start /b /wait "Python_script.py" "%1" "%2" "%3" "%4" "%5"
It worked until python itself started to run exe file.
Once again I tried a lot of combinations:
os.system([exe, arg1, arg2, ...]) and
subprocess.call(..) and subprocess.check_output(..)
-> I either didn't see the output in eclipse console, or the output was delayed or there was only python / or only exe's output in console.
finally I used subprocess.Popen(...) and it's nearly allright - the only defect is that the output from python script don't wait for exe's process to finish, and when I use subprocess.Popen(...).wait() exe passes output to console but the WHOLE output from python script is delayed until the 'exe' terminates. I want to delay only the part of pythons script output that is written after the exe is called.
how to achieve this 'partly console output delay' is the main topic
advices on python and eclipse .launch configuration will be appreciated
general advices on how does the communication between this processes(?) work will be appreciated
Thanks!
It sounds to me like you have three different processes you're trying to get to work together, you've tried a whole bunch of stuff to get it working, and the code is complex enough that you can't easily post it here. That makes it pretty hard to get a good answer (Stack Overflow works much better with focused questions), but here's the general approach I'd take:
Does your script run if you try to run Python_script.py directly from the command prompt?
If it doesn't, then look into registering the .py file type in Windows.
If it does, then maybe Eclipse launch configurations don't support or don't properly support Windows registered file types. There should be no need to mess with batch files and start; just replace Python_script.py in your launch configuration with c:\Python27\python.exe Python_script.py (or similar).
Get your script working from a command prompt - able to run, with proper Python and subprocess output, and waiting for everything to terminate.
If things work from the command prompt and still don't work from Eclipse, then post a new question with a small snippet of code showing what you're trying and a description of what's wrong. subprocess.call, subprocess.check_output, and Popen all have different uses, so it's hard to give general advice besides just referring to the documentation.
I know how to set-up run configurations to pass parameters to a specific python script. There are several entry points, I don't want a run configuration for each one do I? What I want to do instead is launch a python script from a command line shell script and be able to attach the PyCharm debugger to the python script that is executed and have it stop at break points. I've tried to use a pre-launch condition of a utility python script that will sleep for 10 seconds so I can attempt to "attach to process" of the python script. That didn't work. I tried to import pdb and settrace to see if that would stop it for attaching to the process, but that looks to be command line debugging specific only. Any clues would be appreciated.
Thanks!
You can attach the debugger to a python process launched from terminal:
Use Menu Tools --> Attach to process then select python process to debug.
If you want to debug a file installed in site-packages you may need to open the file from its original location.
You can to pause the program manually from debugger and inspect the suspended Thread to find your source file.
I'd like to call a separate non-child python program from a python script and have it run externally in a new shell instance. The original python script doesn't need to be aware of the instance it launches, it shouldn't block when the launched process is running and shouldn't care if it dies. This is what I have tried which returns no error but seems to do nothing...
import subprocess
python_path = '/usr/bin/python'
args = [python_path, '&']
p = subprocess.Popen(args, shell=True)
What should I be doing differently
EDIT
The reason for doing this is I have an application with a built in version of python, I have written some python tools that should be run separately alongside this application but there is no assurance that the user will have python installed on their system outside the application with the builtin version I'm using. Because of this I can get the python binary path from the built in version programatically and I'd like to launch an external version of the built in python. This eliminates the need for the user to install python themselves. So in essence I need a simple way to call an external python script using my current running version of python programatically.
I don't need to catch any output into the original program, in fact once launched I'd like it to have nothing to do with the original program
EDIT 2
So it seems that my original question was very unclear so here are more details, I think I was trying to over simplify the question:
I'm running OSX but the code should also work on windows machines.
The main application that has a built in version of CPython is a compiled c++ application that ships with a python framework that it uses at runtime. You can launch the embedded version of this version of python by doing this in a Terminal window on OSX
/my_main_app/Contents/Frameworks/Python.framework/Versions/2.7/bin/python
From my main application I'd like to be able to run a command in the version of python embedded in the main app that launches an external copy of a python script using the above python version just like I would if I did the following command in a Terminal window. The new launched orphan process should have its own Terminal window so the user can interact with it.
/my_main_app/Contents/Frameworks/Python.framework/Versions/2.7/bin/python my_python_script
I would like the child python instance not to block the main application and I'd like it to have its own terminal window so the user can interact with it. The main application doesn't need to be aware of the child once its launched in any way. The only reason I would do this is to automate launching an external application using a Terminal for the user
If you're trying to launch a new terminal window to run a new Python in (which isn't what your question asks for, but from a comment it sounds like it's what you actually want):
You can't. At least not in a general-purpose, cross-platform way.
Python is just a command-line program that runs with whatever stdin/stdout/stderr it's given. If those happen to be from a terminal, then it's running in a terminal. It doesn't know anything about the terminal beyond that.
If you need to do this for some specific platform and some specific terminal program—e.g., Terminal.app on OS X, iTerm on OS X, the "DOS prompt" on Windows, gnome-terminal on any X11 system, etc.—that's generally doable, but the way to do it is by launching or scripting the terminal program and telling it to open a new window and run Python in that window. And, needless to say, they all have completely different ways of doing that.
And even then, it's not going to be possible in all cases. For example, if you ssh in to a remote machine and run Python on that machine, there is no way it can reach back to your machine and open a new terminal window.
On most platforms that have multiple possible terminals, you can write some heuristic code that figures out which terminal you're currently running under by just walking os.getppid() until you find something that looks like a terminal you know how to deal with (and if you get to init/launchd/etc. without finding one, then you weren't running in a terminal).
The problem is that you're running Python with the argument &. Python has no idea what to do with that. It's like typing this at the shell:
/usr/bin/python '&'
In fact, if you pay attention, you're almost certainly getting something like this through your stderr:
python: can't open file '&': [Errno 2] No such file or directory
… which is exactly what you'd get from doing the equivalent at the shell.
What you presumably wanted was the equivalent of this shell command:
/usr/bin/python &
But the & there isn't an argument at all, it's part of sh syntax. The subprocess module doesn't know anything about sh syntax, and you're telling it not to use a shell, so there's nobody to interpret that &.
You could tell subprocess to use a shell, so it can do this for you:
cmdline = '{} &'.format(python_path)
p = subprocess.Popen(cmdline, shell=True)
But really, there's no good reason to. Just opening a subprocess and not calling communicate or wait on it already effectively "puts it in the background", just like & does on the shell. So:
args = [python_path]
p = subprocess.Popen(args)
This will start a new Python interpreter that sits there running in the background, trying to use the same stdin/stdout/stderr as your parent. I'm not sure why you want that, but it's the same thing that using & in the shell would have done.
Actually I think there might be a solution to your problem, I found a useful solution at another question here.
This way subprocess.popen starts a new python shell instance and runs the second script from there. It worked perfectly for me on Windows 10.
You can try using screen command
with this command a new shell instance created and the current instance runs in the background.
# screen; python script1.py
After running above command, a new shell prompt will be seen where we can run another script and script1.py will be running in the background.
Hope it helps.
I'm making a drawing program with python and pygame. I am trying to incorporate a script-fu thing in which the program opens a python live interpreter upon startup and allows the user to execute commands in the interpreter alongside the graphical interface.
My current strategy is to run the main loop inside its own thread, then have the application opened using a bash script that does 'python -i main.py'
Is this a safe/effective/ideal way of doing this? How can I use locks to ensure that commands coming in from the interpreter are executed between main loop iterations?
This is my first time using threads, so please explain to me like I am 7.
Thanks :)
The interpreter won't cooperate with locks you set (since it doesn't know about them). Thus, you cannot guarantee when the code entered by the user will execute.
Consider using the code module to build your own interactive console (it's really easy!). Then you can do the locking every time you go to execute user input.
Why are you using a third party live interpreter? Do you realize that pygame comes with one built in? The documentation is here. This will eliminate all of your problems quite easily.