创造性的stdin和python错误处理

Question

I use a third-party program on Windows10 -- call it SuckySoftware.exe.

This program can launch a python script and do other stuff.

When it launches a python script, unfortunately I don't get a command window launched. This creates three problems:

1) I can't give it input. For example using python3 and having "input()" as one of the commands causes SuckySoftware.exe to hang, because it is waiting for input into some non-existent command window.

2) I can't get output. So "print('hello')" doesn't show up anywhere

3) There is no error handling. So if I have a ValueError in my python code, it silently fails on that line and doesn't execute the rest of the python.

I've solved #2 by doing:

sys.stdout = open(logfile, 'wb', 0)
sys.stdout.write('hello'.encode('utf-8'))

and then using mTail to monitor logfile in real-time.

I can't figure out how to solve 1 or 3.

For 1, I wonder if there is a simple way of launching a simple GUI with one textbox. Whenever my logfile shows "Please enter a value" then I could enter it in to that textbox and press enter, and it would take it on stdin. However this seems overly complicated.

For 3, I wonder if I can catch all error messages (including the line number it failed on) and print them to stdout before the script quits.

Ideas?

Answer 1

First, do open a file as sys.stderr , since output there may be useful in any event.

1. The simplest, most portable technique is to set sys.stdin to a (TCP, aka SOCK_STREAM ) socket connection to another process.
2. You can use such a socket as sys.stdout and/or sys.stderr as well, although then the helper process has to use select to handle the multiple streams without deadlock. (You might want to use a wrapper as sys.stderr to preserve its unbuffered status.)
3. Assign a function to sys.excepthook that reports the exception via (your) stderr . (There is perhaps something already assigning such a function, since nothing shows up on sys.stderr as it is.)