[bug]: After generation, two keyboard interrupts needed to shut down server

[lstein]

Is there an existing issue for this problem?

• I have searched the existing issues

Install method

Invoke's Launcher

Operating system

Linux

GPU vendor

Nvidia (CUDA)

GPU model

No response

GPU VRAM

No response

Version number

lstein/feature/elegant-shutdown branch

Browser

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System Information

No response

What happened

The branch lstein/feature/elegant-shutdown is supposed to make it possible to shut down the server by pressing the ^C (keyboard interrupt) key just once, rather than requiring two presses.

Currently, after any generation has occurred, pressing ^C gives this message followed by an indefinite hang:

^C[2026-03-02 08:56:20,522]::[ModelInstallService]::INFO --> Installer thread 132929897526976 exiting
[2026-03-02 08:56:20,536]::[InvokeAI]::INFO --> InvokeAI shutting down...

Pressing ^C again gives a short stack trace and the server finally does exit:

^CException ignored in: <module 'threading' from '/home/lstein/.local/share/uv/python/cpython-3.12.12-linux-x86_64-gnu/lib/python3.12/threading.py'>
Traceback (most recent call last):
  File "/home/lstein/.local/share/uv/python/cpython-3.12.12-linux-x86_64-gnu/lib/python3.12/threading.py", line 1624, in _shutdown
    lock.acquire()
KeyboardInterrupt: 

It is likely that there is a thread that is waiting on a lock. Please track this down and fix it.

What you expected to happen

One ^C should be sufficient to shut the server down cleanly.

How to reproduce the problem

No response

Additional context

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Discord username

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