From 3e2854ac30583db239db9713d8ecb02025acc70f Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Sun, 29 Sep 2024 20:00:00 +0100
Subject: [PATCH 01/13] add socket-load-balance flag

---
 tests/test_subprocess.py |  4 ++--
 uvicorn/_subprocess.py   | 44 +++++++++++++++++++++++++++++++++++-----
 uvicorn/config.py        |  2 ++
 uvicorn/main.py          | 19 +++++++++++++----
 4 files changed, 58 insertions(+), 11 deletions(-)

diff --git a/tests/test_subprocess.py b/tests/test_subprocess.py
index 93191bacb..7b5d0ef40 100644
--- a/tests/test_subprocess.py
+++ b/tests/test_subprocess.py
@@ -3,7 +3,7 @@
 import socket
 from unittest.mock import patch
 
-from uvicorn._subprocess import SpawnProcess, get_subprocess, subprocess_started
+from uvicorn._subprocess import SocketSharePickle, SpawnProcess, get_subprocess, subprocess_started
 from uvicorn._types import ASGIReceiveCallable, ASGISendCallable, Scope
 from uvicorn.config import Config
 
@@ -36,7 +36,7 @@ def test_subprocess_started() -> None:
 
     with patch("tests.test_subprocess.server_run") as mock_run:
         with patch.object(config, "configure_logging") as mock_config_logging:
-            subprocess_started(config, server_run, [fdsock], None)
+            subprocess_started(config, server_run, [SocketSharePickle(fdsock)], None)
             mock_run.assert_called_once()
             mock_config_logging.assert_called_once()
 
diff --git a/uvicorn/_subprocess.py b/uvicorn/_subprocess.py
index 1c06844de..ea99681b6 100644
--- a/uvicorn/_subprocess.py
+++ b/uvicorn/_subprocess.py
@@ -7,9 +7,9 @@
 
 import multiprocessing
 import os
+import socket
 import sys
 from multiprocessing.context import SpawnProcess
-from socket import socket
 from typing import Callable
 
 from uvicorn.config import Config
@@ -18,10 +18,39 @@
 spawn = multiprocessing.get_context("spawn")
 
 
+class SocketSharePickle:
+    def __init__(self, sock: socket.socket):
+        self._sock = sock
+
+    def get(self) -> socket.socket:
+        return self._sock
+
+
+class SocketShareRebind:
+    def __init__(self, sock: socket.socket):
+        if (sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB"):
+            raise RuntimeError("socket_load_balance not supported")
+        sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
+        self._family = sock.family
+        self._sockname = sock.getsockname()
+
+    def get(self) -> socket.socket:
+        try:
+            sock = socket.socket(family=self._family)
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
+
+            sock.bind(self._sockname)
+            return sock
+        except BaseException:
+            sock.close()
+            raise
+
+
 def get_subprocess(
     config: Config,
     target: Callable[..., None],
-    sockets: list[socket],
+    sockets: list[socket.socket],
 ) -> SpawnProcess:
     """
     Called in the parent process, to instantiate a new child process instance.
@@ -41,10 +70,15 @@ def get_subprocess(
     except (AttributeError, OSError):
         stdin_fileno = None
 
+    socket_shares: list[SocketShareRebind] | list[SocketSharePickle]
+    if config.socket_load_balance:
+        socket_shares = [SocketShareRebind(s) for s in sockets]
+    else:
+        socket_shares = [SocketSharePickle(s) for s in sockets]
     kwargs = {
         "config": config,
         "target": target,
-        "sockets": sockets,
+        "sockets": socket_shares,
         "stdin_fileno": stdin_fileno,
     }
 
@@ -54,7 +88,7 @@ def get_subprocess(
 def subprocess_started(
     config: Config,
     target: Callable[..., None],
-    sockets: list[socket],
+    sockets: list[SocketSharePickle] | list[SocketShareRebind],
     stdin_fileno: int | None,
 ) -> None:
     """
@@ -77,7 +111,7 @@ def subprocess_started(
 
     try:
         # Now we can call into `Server.run(sockets=sockets)`
-        target(sockets=sockets)
+        target(sockets=[s.get() for s in sockets])
     except KeyboardInterrupt:  # pragma: no cover
         # supress the exception to avoid a traceback from subprocess.Popen
         # the parent already expects us to end, so no vital information is lost
diff --git a/uvicorn/config.py b/uvicorn/config.py
index 9aff8c968..54a2f9b3f 100644
--- a/uvicorn/config.py
+++ b/uvicorn/config.py
@@ -223,6 +223,7 @@ def __init__(
         headers: list[tuple[str, str]] | None = None,
         factory: bool = False,
         h11_max_incomplete_event_size: int | None = None,
+        socket_load_balance: bool = False,
     ):
         self.app = app
         self.host = host
@@ -268,6 +269,7 @@ def __init__(
         self.encoded_headers: list[tuple[bytes, bytes]] = []
         self.factory = factory
         self.h11_max_incomplete_event_size = h11_max_incomplete_event_size
+        self.socket_load_balance = socket_load_balance
 
         self.loaded = False
         self.configure_logging()
diff --git a/uvicorn/main.py b/uvicorn/main.py
index 43956622d..755fb4a06 100644
--- a/uvicorn/main.py
+++ b/uvicorn/main.py
@@ -360,6 +360,13 @@ def print_version(ctx: click.Context, param: click.Parameter, value: bool) -> No
     help="Treat APP as an application factory, i.e. a () -> <ASGI app> callable.",
     show_default=True,
 )
+@click.option(
+    "--socket-load-balance",
+    is_flag=True,
+    default=False,
+    help="Use kernel support for socket load balancing",
+    show_default=True,
+)
 def main(
     app: str,
     host: str,
@@ -408,6 +415,7 @@ def main(
     app_dir: str,
     h11_max_incomplete_event_size: int | None,
     factory: bool,
+    socket_load_balance: bool = False,
 ) -> None:
     run(
         app,
@@ -457,6 +465,7 @@ def main(
         factory=factory,
         app_dir=app_dir,
         h11_max_incomplete_event_size=h11_max_incomplete_event_size,
+        socket_load_balance=socket_load_balance,
     )
 
 
@@ -509,6 +518,7 @@ def run(
     app_dir: str | None = None,
     factory: bool = False,
     h11_max_incomplete_event_size: int | None = None,
+    socket_load_balance: bool = False,
 ) -> None:
     if app_dir is not None:
         sys.path.insert(0, app_dir)
@@ -560,6 +570,7 @@ def run(
         use_colors=use_colors,
         factory=factory,
         h11_max_incomplete_event_size=h11_max_incomplete_event_size,
+        socket_load_balance=socket_load_balance,
     )
     server = Server(config=config)
 
@@ -570,11 +581,11 @@ def run(
 
     try:
         if config.should_reload:
-            sock = config.bind_socket()
-            ChangeReload(config, target=server.run, sockets=[sock]).run()
+            with config.bind_socket() as sock:
+                ChangeReload(config, target=server.run, sockets=[sock]).run()
         elif config.workers > 1:
-            sock = config.bind_socket()
-            Multiprocess(config, target=server.run, sockets=[sock]).run()
+            with config.bind_socket() as sock:
+                Multiprocess(config, target=server.run, sockets=[sock]).run()
         else:
             server.run()
     except KeyboardInterrupt:

From 1550e7a10d3d974f55ff93dde22bb0316e120ab3 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:12:10 +0100
Subject: [PATCH 02/13] fix it so it actually runs

---
 uvicorn/_subprocess.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/uvicorn/_subprocess.py b/uvicorn/_subprocess.py
index ea99681b6..8390f83ce 100644
--- a/uvicorn/_subprocess.py
+++ b/uvicorn/_subprocess.py
@@ -28,15 +28,17 @@ def get(self) -> socket.socket:
 
 class SocketShareRebind:
     def __init__(self, sock: socket.socket):
-        if (sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB"):
+        if not (sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB"):
             raise RuntimeError("socket_load_balance not supported")
         sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
         self._family = sock.family
+        self._type = sock.type
+        self._proto = sock.proto
         self._sockname = sock.getsockname()
 
     def get(self) -> socket.socket:
         try:
-            sock = socket.socket(family=self._family)
+            sock = socket.socket(family=self._family, type=self._type, proto=self._proto)
             sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
             sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
 

From 4a0785af6541dff4a1985794e18549ee8a5cfead Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:12:27 +0100
Subject: [PATCH 03/13] add a test

---
 tests/supervisors/test_multiprocess.py | 61 +++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index e1f594efe..fdfab920a 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -1,17 +1,21 @@
 from __future__ import annotations
 
 import functools
+import multiprocessing
 import os
 import signal
 import socket
+import sys
 import threading
 import time
-from typing import Any, Callable
+from typing import Any, Callable, TypeVar
 
+import httpx
 import pytest
 
 from uvicorn import Config
 from uvicorn._types import ASGIReceiveCallable, ASGISendCallable, Scope
+from uvicorn.server import Server
 from uvicorn.supervisors import Multiprocess
 from uvicorn.supervisors.multiprocess import Process
 
@@ -169,3 +173,58 @@ def test_multiprocess_sigttou() -> None:
     assert len(supervisor.processes) == 1
     supervisor.signal_queue.append(signal.SIGINT)
     supervisor.join_all()
+
+
+T = TypeVar("T")
+
+
+class Box:
+    def __init__(self, v: T):
+        self.v = v
+
+
+async def lb_app(
+    d: multiprocessing.managers.DictProxy, scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable
+) -> None:
+    if scope["type"] == "lifespan":
+        await receive()
+        print("lifespan started")
+        scope["state"]["count"] = box = Box(0)
+        await send({"type": "lifespan.startup.complete"})
+        await receive()
+        d[os.getpid()] = box.v
+        await send({"type": "lifespan.shutdown.complete"})
+        return
+
+    scope["state"]["count"].v += 1
+    headers = [(b"content-type", b"text/plain")]
+    await send({"type": "http.response.start", "status": 200, "headers": headers})
+    await send({"type": "http.response.body", "body": b"hello"})
+
+
+@pytest.mark.skipif(
+    not ((sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB")),
+    reason="unsupported",
+    strict=True,
+    raises=RuntimeError,
+)
+def test_multiprocess_socket_balance() -> None:
+    with multiprocessing.Manager() as m:
+        d = m.dict()
+        app = functools.partial(lb_app, d)
+        config = Config(app=app, workers=2, socket_load_balance=True, port=0, interface="asgi3")
+        server = Server(config=config)
+        with config.bind_socket() as sock:
+            port = sock.getsockname()[1]
+            try:
+                supervisor = Multiprocess(config, target=server.run, sockets=[sock])
+                threading.Thread(target=supervisor.run, daemon=True).start()
+                time.sleep(1)
+                with httpx.Client():
+                    for i in range(100):
+                        httpx.get(f"http://localhost:{port}/").raise_for_status()
+            finally:
+                supervisor.signal_queue.append(signal.SIGINT)
+                supervisor.join_all()
+        min_conn, max_conn = sorted(d.values())
+        assert max_conn - min_conn < 20

From 2a9b20a7fa00203b05651563fa3c4d11af0da39b Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:16:04 +0100
Subject: [PATCH 04/13] mypy fix

---
 tests/supervisors/test_multiprocess.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index fdfab920a..1e1a978b2 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -205,7 +205,6 @@ async def lb_app(
 @pytest.mark.skipif(
     not ((sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB")),
     reason="unsupported",
-    strict=True,
     raises=RuntimeError,
 )
 def test_multiprocess_socket_balance() -> None:

From 0af6480dd6830602bbc650fa46e2b297aa755d6c Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:19:45 +0100
Subject: [PATCH 05/13] mypy fix 2

---
 tests/supervisors/test_multiprocess.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index 1e1a978b2..f13accac8 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -205,7 +205,6 @@ async def lb_app(
 @pytest.mark.skipif(
     not ((sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB")),
     reason="unsupported",
-    raises=RuntimeError,
 )
 def test_multiprocess_socket_balance() -> None:
     with multiprocessing.Manager() as m:

From d9c117a2f3c0c9bae078a1b7db1a149fba8ad324 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:26:06 +0100
Subject: [PATCH 06/13] add cli usage

---
 docs/deployment.md | 1 +
 docs/index.md      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/docs/deployment.md b/docs/deployment.md
index e1854deff..212d40265 100644
--- a/docs/deployment.md
+++ b/docs/deployment.md
@@ -135,6 +135,7 @@ Options:
                                   buffer of an incomplete event.
   --factory                       Treat APP as an application factory, i.e. a
                                   () -> <ASGI app> callable.
+  --socket-load-balance           Use kernel support for socket load balancing
   --help                          Show this message and exit.
 ```
 
diff --git a/docs/index.md b/docs/index.md
index bb6fc321a..e9bf5b3b5 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -205,6 +205,7 @@ Options:
                                   buffer of an incomplete event.
   --factory                       Treat APP as an application factory, i.e. a
                                   () -> <ASGI app> callable.
+  --socket-load-balance           Use kernel support for socket load balancing
   --help                          Show this message and exit.
 ```
 

From 66afb6229a5f232c42278b2371aec76943e173b9 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:39:16 +0100
Subject: [PATCH 07/13] remove print and sleep

---
 tests/supervisors/test_multiprocess.py | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index f13accac8..f9a7e7702 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 import functools
-import multiprocessing
+import multiprocessing.managers
 import os
 import signal
 import socket
@@ -184,13 +184,17 @@ def __init__(self, v: T):
 
 
 async def lb_app(
-    d: multiprocessing.managers.DictProxy, scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable
+    d: multiprocessing.managers.DictProxy,
+    started: threading.Event,
+    scope: Scope,
+    receive: ASGIReceiveCallable,
+    send: ASGISendCallable,
 ) -> None:
     if scope["type"] == "lifespan":
         await receive()
-        print("lifespan started")
         scope["state"]["count"] = box = Box(0)
         await send({"type": "lifespan.startup.complete"})
+        started.set()
         await receive()
         d[os.getpid()] = box.v
         await send({"type": "lifespan.shutdown.complete"})
@@ -208,8 +212,9 @@ async def lb_app(
 )
 def test_multiprocess_socket_balance() -> None:
     with multiprocessing.Manager() as m:
+        started = m.Event()
         d = m.dict()
-        app = functools.partial(lb_app, d)
+        app = functools.partial(lb_app, d, started)
         config = Config(app=app, workers=2, socket_load_balance=True, port=0, interface="asgi3")
         server = Server(config=config)
         with config.bind_socket() as sock:
@@ -217,7 +222,8 @@ def test_multiprocess_socket_balance() -> None:
             try:
                 supervisor = Multiprocess(config, target=server.run, sockets=[sock])
                 threading.Thread(target=supervisor.run, daemon=True).start()
-                time.sleep(1)
+                if not started.wait(timeout=5):
+                    raise TimeoutError
                 with httpx.Client():
                     for i in range(100):
                         httpx.get(f"http://localhost:{port}/").raise_for_status()
@@ -225,4 +231,4 @@ def test_multiprocess_socket_balance() -> None:
                 supervisor.signal_queue.append(signal.SIGINT)
                 supervisor.join_all()
         min_conn, max_conn = sorted(d.values())
-        assert max_conn - min_conn < 20
+        assert (max_conn - min_conn) < 25

From 4166deed90676468dd564ab51f8c264ceba4a05a Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:48:00 +0100
Subject: [PATCH 08/13] add coverage pragmas

---
 tests/supervisors/test_multiprocess.py |  4 ++--
 uvicorn/_subprocess.py                 | 15 ++++++++-------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index f9a7e7702..1860c9ccb 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -189,7 +189,7 @@ async def lb_app(
     scope: Scope,
     receive: ASGIReceiveCallable,
     send: ASGISendCallable,
-) -> None:
+) -> None:  # pragma: py-darwin pragma: py-win32
     if scope["type"] == "lifespan":
         await receive()
         scope["state"]["count"] = box = Box(0)
@@ -210,7 +210,7 @@ async def lb_app(
     not ((sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB")),
     reason="unsupported",
 )
-def test_multiprocess_socket_balance() -> None:
+def test_multiprocess_socket_balance() -> None:  # pragma: py-darwin pragma: py-win32
     with multiprocessing.Manager() as m:
         started = m.Event()
         d = m.dict()
diff --git a/uvicorn/_subprocess.py b/uvicorn/_subprocess.py
index 8390f83ce..1433cb6fa 100644
--- a/uvicorn/_subprocess.py
+++ b/uvicorn/_subprocess.py
@@ -30,13 +30,14 @@ class SocketShareRebind:
     def __init__(self, sock: socket.socket):
         if not (sys.platform == "linux" and hasattr(socket, "SO_REUSEPORT")) or hasattr(socket, "SO_REUSEPORT_LB"):
             raise RuntimeError("socket_load_balance not supported")
-        sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
-        self._family = sock.family
-        self._type = sock.type
-        self._proto = sock.proto
-        self._sockname = sock.getsockname()
+        else:  # pragma: py-darwin pragma: py-win32
+            sock.setsockopt(socket.SOL_SOCKET, getattr(socket, "SO_REUSEPORT_LB", socket.SO_REUSEPORT), 1)
+            self._family = sock.family
+            self._type = sock.type
+            self._proto = sock.proto
+            self._sockname = sock.getsockname()
 
-    def get(self) -> socket.socket:
+    def get(self) -> socket.socket:  # pragma: py-darwin pragma: py-win32
         try:
             sock = socket.socket(family=self._family, type=self._type, proto=self._proto)
             sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
@@ -73,7 +74,7 @@ def get_subprocess(
         stdin_fileno = None
 
     socket_shares: list[SocketShareRebind] | list[SocketSharePickle]
-    if config.socket_load_balance:
+    if config.socket_load_balance:  # pragma: py-darwin pragma: py-win32
         socket_shares = [SocketShareRebind(s) for s in sockets]
     else:
         socket_shares = [SocketSharePickle(s) for s in sockets]

From 77a4a23da473b0eb8d497535f6ba767140f05872 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:54:08 +0100
Subject: [PATCH 09/13] change box to dataclass to avoid coverage requirement

---
 tests/supervisors/test_multiprocess.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index 1860c9ccb..cd1b037f3 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import dataclasses
 import functools
 import multiprocessing.managers
 import os
@@ -8,7 +9,7 @@
 import sys
 import threading
 import time
-from typing import Any, Callable, TypeVar
+from typing import Any, Callable, Generic, TypeVar
 
 import httpx
 import pytest
@@ -178,9 +179,9 @@ def test_multiprocess_sigttou() -> None:
 T = TypeVar("T")
 
 
-class Box:
-    def __init__(self, v: T):
-        self.v = v
+@dataclasses.dataclass
+class Box(Generic[T]):
+    v: T
 
 
 async def lb_app(

From d5a1f59be41c6f904abc2b59371e4579895e9648 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 10:58:59 +0100
Subject: [PATCH 10/13] test unsupported

---
 tests/supervisors/test_multiprocess.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index cd1b037f3..5ab02e018 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -233,3 +233,12 @@ def test_multiprocess_socket_balance() -> None:  # pragma: py-darwin pragma: py-
                 supervisor.join_all()
         min_conn, max_conn = sorted(d.values())
         assert (max_conn - min_conn) < 25
+
+
+def test_multiprocess_not_supported(monkeypatch):
+    monkeypatch.delattr(socket, "SO_REUSEPORT")
+    config = Config(app=app, workers=2, socket_load_balance=True, port=0, interface="asgi3")
+    with config.bind_socket() as sock:
+        supervisor = Multiprocess(config, target=run, sockets=[sock])
+        with pytest.raises(RuntimeError, match="socket_load_balance not supported"):
+            supervisor.run()

From bb6dc58eec8a56a1c3220d57fab8dc5a09d99387 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 11:25:33 +0100
Subject: [PATCH 11/13] try to collect coverage

---
 pyproject.toml                         | 2 ++
 scripts/coverage                       | 1 +
 tests/supervisors/test_multiprocess.py | 2 +-
 tests/supervisors/test_reload.py       | 2 +-
 uvicorn/_subprocess.py                 | 2 +-
 5 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index 840ada3a8..3d9b161e2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -103,6 +103,8 @@ filterwarnings = [
 source_pkgs = ["uvicorn", "tests"]
 plugins = ["coverage_conditional_plugin"]
 omit = ["uvicorn/workers.py", "uvicorn/__main__.py"]
+concurrency = ["multiprocessing", "thread"]
+parallel = true
 
 [tool.coverage.report]
 precision = 2
diff --git a/scripts/coverage b/scripts/coverage
index c93e45e85..2d6ea60ee 100755
--- a/scripts/coverage
+++ b/scripts/coverage
@@ -8,4 +8,5 @@ export SOURCE_FILES="uvicorn tests"
 
 set -x
 
+${PREFIX}coverage combine
 ${PREFIX}coverage report
diff --git a/tests/supervisors/test_multiprocess.py b/tests/supervisors/test_multiprocess.py
index 5ab02e018..540c1748a 100644
--- a/tests/supervisors/test_multiprocess.py
+++ b/tests/supervisors/test_multiprocess.py
@@ -223,7 +223,7 @@ def test_multiprocess_socket_balance() -> None:  # pragma: py-darwin pragma: py-
             try:
                 supervisor = Multiprocess(config, target=server.run, sockets=[sock])
                 threading.Thread(target=supervisor.run, daemon=True).start()
-                if not started.wait(timeout=5):
+                if not started.wait(timeout=5):  # pragma: no cover
                     raise TimeoutError
                 with httpx.Client():
                     for i in range(100):
diff --git a/tests/supervisors/test_reload.py b/tests/supervisors/test_reload.py
index 30eea2321..cbe06f6d1 100644
--- a/tests/supervisors/test_reload.py
+++ b/tests/supervisors/test_reload.py
@@ -242,7 +242,7 @@ def test_override_defaults(self, touch_soon) -> None:
                 reload=True,
                 # We need to add *.txt otherwise no regular files will match
                 reload_includes=[".*", "*.txt"],
-                reload_excludes=["*.py"],
+                reload_excludes=["*.py", ".coverage.*"],
             )
             reloader = self._setup_reloader(config)
 
diff --git a/uvicorn/_subprocess.py b/uvicorn/_subprocess.py
index 1433cb6fa..65c0c7158 100644
--- a/uvicorn/_subprocess.py
+++ b/uvicorn/_subprocess.py
@@ -45,7 +45,7 @@ def get(self) -> socket.socket:  # pragma: py-darwin pragma: py-win32
 
             sock.bind(self._sockname)
             return sock
-        except BaseException:
+        except BaseException:  # pragma: no cover
             sock.close()
             raise
 

From 47924f253fd10fef64b7076babe0b795d72856e2 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 12:05:48 +0100
Subject: [PATCH 12/13] enable sigterm hook

---
 pyproject.toml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pyproject.toml b/pyproject.toml
index 3d9b161e2..7142ee758 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -105,6 +105,7 @@ plugins = ["coverage_conditional_plugin"]
 omit = ["uvicorn/workers.py", "uvicorn/__main__.py"]
 concurrency = ["multiprocessing", "thread"]
 parallel = true
+sigterm = true
 
 [tool.coverage.report]
 precision = 2

From 577c0570eb4a2a4697215bce10a04a817209aa61 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Tue, 1 Oct 2024 12:06:29 +0100
Subject: [PATCH 13/13] ignore coverage files that show up in reloader tests

---
 tests/supervisors/test_reload.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/supervisors/test_reload.py b/tests/supervisors/test_reload.py
index cbe06f6d1..e54422898 100644
--- a/tests/supervisors/test_reload.py
+++ b/tests/supervisors/test_reload.py
@@ -157,7 +157,7 @@ def test_should_not_reload_when_exclude_pattern_match_file_is_changed(self, touc
                 app="tests.test_config:asgi_app",
                 reload=True,
                 reload_includes=["*"],
-                reload_excludes=["*.js"],
+                reload_excludes=["*.js", ".coverage.*"],
             )
             reloader = self._setup_reloader(config)