[BUG] Progress(): Terminal size mis-detected if run in multiprocessing sub-process

Describe the bug Using multiprocessing to run a sub process, initializing Progress() under that process fails to detect the terminal size, using the fallback (80, 25) instead.

To Reproduce Sample code:

from multiprocessing import Process, Queue

from rich.console import Console
from rich.progress import Progress


def sub_process():
    pre_console = Console()
    print(f"Sub process PRE console size: {pre_console.size}\n")

    with Progress() as progress:
        print(f"Sub process progress.console.size: {progress.console.size}")

        console = Console()
        print(f"Sub process console size: {console.size}\n")


if __name__ == "__main__":
    with Progress() as main_progress:

        print(f"Main progress.console.size: {main_progress.console.size}")

        main_console = Console()
        print(f"Main console size: {main_console.size}\n")

        q = Queue()
        process = Process(target=sub_process)
        process.start()
        process.join()

Output is:

Main progress.console.size: ConsoleDimensions(width=151, height=45)
Main console size: ConsoleDimensions(width=151, height=45)

Sub process PRE console size: ConsoleDimensions(width=151, height=45)

Sub process progress.console.size: ConsoleDimensions(width=80, height=25)
Sub process console size: ConsoleDimensions(width=80, height=25)

-> Note the difference between the 3 variants:

• instances in main module (correct terminal size)
• instance in sub process, before Progress() is called (correct)
• instances in sub process, after Progress() is called (fallback)

Platform Macos 11.4 (Big Sur) iTerm 2 python 3.9.4

Diagnose I may ask you to cut and paste the output of the following commands. It may save some time if you do it now.

rich.diagnose

╭───────────────────────── <class 'rich.console.Console'> ─────────────────────────╮
│ A high level console interface.                                                  │
│                                                                                  │
│ ╭──────────────────────────────────────────────────────────────────────────────╮ │
│ │ <console width=151 ColorSystem.TRUECOLOR>                                    │ │
│ ╰──────────────────────────────────────────────────────────────────────────────╯ │
│                                                                                  │
│     color_system = 'truecolor'                                                   │
│         encoding = 'utf-8'                                                       │
│             file = <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'> │
│           height = 45                                                            │
│    is_alt_screen = False                                                         │
│ is_dumb_terminal = False                                                         │
│   is_interactive = True                                                          │
│       is_jupyter = False                                                         │
│      is_terminal = True                                                          │
│   legacy_windows = False                                                         │
│         no_color = False                                                         │
│          options = ConsoleOptions(                                               │
│                        size=ConsoleDimensions(width=151, height=45),             │
│                        legacy_windows=False,                                     │
│                        min_width=1,                                              │
│                        max_width=151,                                            │
│                        is_terminal=True,                                         │
│                        encoding='utf-8',                                         │
│                        justify=None,                                             │
│                        overflow=None,                                            │
│                        no_wrap=False,                                            │
│                        highlight=None,                                           │
│                        markup=None,                                              │
│                        height=None                                               │
│                    )                                                             │
│            quiet = False                                                         │
│           record = False                                                         │
│         safe_box = True                                                          │
│             size = ConsoleDimensions(width=151, height=45)                       │
│        soft_wrap = False                                                         │
│           stderr = False                                                         │
│            style = None                                                          │
│         tab_size = 8                                                             │
│            width = 151                                                           │
╰──────────────────────────────────────────────────────────────────────────────────╯

rich._windows

platform="Darwin"
WindowsConsoleFeatures(vt=False, truecolor=False)

pip freeze | grep rich

rich==10.2.2

** Workaround ** Initalize a Console() with width and height from shutil.get_terminal_size(), then initialize Progress() with that console:

    terminal_size: os.terminal_size = shutil.get_terminal_size()
    console = Console(width=terminal_size.columns, height=terminal_size.lines)
    progress = Progress(console=console)

It would seem that Console() only uses shutil.get_terminal_size() under Windows. Otherwise it uses os.get_terminal_size() for stdin or stdout - but I guess (I haven’t fully explored your code, sorry) that the redirects that are enabled by Progress() / Live(), coupled with the multiprocessing, somehow mess that up. Perhaps shutil could be tried first, regardless of platform?

Thanks for an awesome library!

[willmcgugan]

Please try 10.6.0 It will use sys.stdin etc. so it should still work even when wrapper.

[mboquien]

I ran into the same issue and the new release appears to have solved it. Thanks a lot!