From 99dbf3006b30dd77a0f650b25d9b1c8071f25e1e Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Sat, 25 Jan 2025 09:28:06 -0800
Subject: [PATCH] Cache executor to avoid hitting open file limits (#4560)

Fixes #4504, fixes #3251
---
 src/blackd/__init__.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/blackd/__init__.py b/src/blackd/__init__.py
index d51b9ce..86309da 100644
--- a/src/blackd/__init__.py
+++ b/src/blackd/__init__.py
@@ -2,7 +2,7 @@
 import logging
 from concurrent.futures import Executor, ProcessPoolExecutor
 from datetime import datetime, timezone
-from functools import partial
+from functools import cache, partial
 from multiprocessing import freeze_support
 
 try:
@@ -85,12 +85,16 @@ def main(bind_host: str, bind_port: int) -> None:
     web.run_app(app, host=bind_host, port=bind_port, handle_signals=True, print=None)
 
 
+@cache
+def executor() -> Executor:
+    return ProcessPoolExecutor()
+
+
 def make_app() -> web.Application:
     app = web.Application(
         middlewares=[cors(allow_headers=(*BLACK_HEADERS, "Content-Type"))]
     )
-    executor = ProcessPoolExecutor()
-    app.add_routes([web.post("/", partial(handle, executor=executor))])
+    app.add_routes([web.post("/", partial(handle, executor=executor()))])
     return app