Python "breakpoint()" with VSCode

vscode_debugger.py

import os
import sys
import debugpy

# Based on
# https://stackoverflow.com/questions/69690653/remote-debugging-with-debugpy-works-from-code-but-not-from-command-line

# To use with 'breakpoint()'
# export PYTHONBREAKPOINT=vscode_debugger.wait_for_vscode

"""
VS Code configuration
    Add the following to the "configurations" in your launch.json.

    You can get the port number by running (To avoid clashes with multiple users):
    python -c 'import os; print((20000 + os.getuid()) % 65536)'    

    {
        "name": "Python: Attach to process",
        "type": "python",
        "request": "attach",
        "connect": {
            "host": "localhost",
            "port": 21001 // Refer comment above or 5678 for Windows
        }
    }

Using this in code:
    To use with `breakpoint()` set `PYTHONBREAKPOINT=vscode_debugger.wait_for_vscode` before execution.
    
    Alternatively,
        `from vscode_debugger import *`

    Add 'wait_for_vscode()' just before the line you want a breakpoint.
    Alternately, add @vscode_debug decorator to any function you want a breakpoint.

    Once the debugger connects, execution slows down.
    You can speed it up a bit by adding 'disable_debugpy()' at the point
    where you don't need a debugger. Breakpoints/stepping won't work after the
    'disable_debugpy()' line
"""


LISTEN_ACTIVE = False
DEBUG_PORT = 5678
if hasattr(os, getuid):
    DEBUG_PORT = (30000 + os.getuid()) % 65536 # Edit if on Windows


def disable_debugpy():
    debugpy.server.api.get_global_debugger().disable_tracing()
    print("Disabling debugpy trace", file=sys.stderr)


def wait_for_vscode(cond=True, breakpoint=True):
    global LISTEN_ACTIVE
    if not LISTEN_ACTIVE:
        debugpy.listen(("localhost", DEBUG_PORT))
        LISTEN_ACTIVE = True
    if cond and not debugpy.is_client_connected():
        print("Wait for DebugPy connection...", file=sys.stderr)
        debugpy.wait_for_client()
    if cond:
        debugpy.breakpoint()


def vscode_debug_exception(func, *args, **kwargs):
    def inner():
        try:
            return func(*args, **kwargs)
        except Exception as e:
            import traceback; traceback.print_exc()
            print(f"Exception: {type(e)}: {e} occured",
                  f"Will exit function: '{func.__name__}' and resume from there",
                  file=sys.stderr)
            wait_for_vscode()
    return inner


def vscode_debug(func, *args, **kwargs):
    def inner():
        wait_for_vscode()
        ret_val = func(*args, **kwargs)
        disable_debugpy()
        return ret_val
    return inner


@vscode_debug_exception
def example_exception():
    print("Raising NameError Exception")
    raise NameError
    print("This will not execute!!")


@vscode_debug
def example_function():
    print("Debugpy waits at start of function")


def example_breakpoint1():
    try:
        raise NameError
    except:
        print("Wait for DebugPy connection")
        wait_for_vscode()
        print("Debugger will not execute this line before connection")


def example_breakpoint2():
    try:
        raise NameError
    except:
        print("Wait for DebugPy connection")
        breakpoint() # Will work if export PYTHONBREAKPOINT=vscode_debugger.wait_for_vscode
        print("This will execute after debugger is connected")

def check_execution_speed():
    import time
    start_time = time.time()
    _ = [x for x in range(1, 100000000)]
    runtime = time.time() - start_time
    print(f"Runtime: {runtime} seconds", flush=True)


def main():
    for i in range(1, 10):
        wait_for_vscode(cond=(i==5))
        print(i)

    example_exception()
    example_function()
    example_breakpoint1()
    example_breakpoint2()

    # When debugger is connected, execution speed drops.
    # disable_debugpy() improves the speed, but not fully back to original levels.
    check_execution_speed()
    disable_debugpy() # Stepping/Breakpoints cannot work after this point.
    check_execution_speed()


if __name__ == "__main__":
    main()