Adapt bind_socket to make it usable with multiple processes

tests/test_config.py

@@ -355,3 +355,47 @@ def test_ws_max_size() -> None:
     config = Config(app=asgi_app, ws_max_size=1000)
     config.load()
     assert config.ws_max_size == 1000
+
+
+@pytest.mark.parametrize(
+    "reload, workers",
+    [
+        (True, 1),
+        (False, 2),
+    ],
+    ids=["--reload=True --workers=1", "--reload=False --workers=2"],
+)
+@pytest.mark.skipif(sys.platform == "win32", reason="require unix-like system")
+def test_bind_unix_socket_works_with_reload_or_workers(tmp_path, reload, workers):
+    uds_file = tmp_path / "uvicorn.sock"
+    config = Config(
+        app=asgi_app, uds=uds_file.as_posix(), reload=reload, workers=workers
+    )
+    config.load()
+    sock = config.bind_socket()
+    assert isinstance(sock, socket.socket)
+    assert sock.family == socket.AF_UNIX
+    assert sock.getsockname() == uds_file.as_posix()
+    sock.close()
+
+
+@pytest.mark.parametrize(
+    "reload, workers",
+    [
+        (True, 1),
+        (False, 2),
+    ],
+    ids=["--reload=True --workers=1", "--reload=False --workers=2"],
+)
+@pytest.mark.skipif(sys.platform == "win32", reason="require unix-like system")
+def test_bind_fd_works_with_reload_or_workers(reload, workers):
+    fdsock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    fd = fdsock.fileno()
+    config = Config(app=asgi_app, fd=fd, reload=reload, workers=workers)
+    config.load()
+    sock = config.bind_socket()
+    assert isinstance(sock, socket.socket)
+    assert sock.family == socket.AF_UNIX
+    assert sock.getsockname() == ""
+    sock.close()
+    fdsock.close()

uvicorn/config.py

@@ -395,37 +395,63 @@ def setup_event_loop(self) -> None:
             loop_setup()
 
     def bind_socket(self) -> socket.socket:
-        family = socket.AF_INET
-        addr_format = "%s://%s:%d"
+        logger_args: List[Union[str, int]]
+        if self.uds:
+            path = self.uds
+            sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+            try:
+                sock.bind(path)
+                uds_perms = 0o666
+                os.chmod(self.uds, uds_perms)
+            except OSError as exc:
+                logger.error(exc)
+                sys.exit(1)
 
-        if self.host and ":" in self.host:
-            # It's an IPv6 address.
-            family = socket.AF_INET6
-            addr_format = "%s://[%s]:%d"
+            message = "Uvicorn running on unix socket %s (Press CTRL+C to quit)"
+            sock_name_format = "%s"
+            color_message = (
+                "Uvicorn running on "
+                + click.style(sock_name_format, bold=True)
+                + " (Press CTRL+C to quit)"
+            )
+            logger_args = [self.uds]
+        elif self.fd:
+            sock = socket.fromfd(self.fd, socket.AF_UNIX, socket.SOCK_STREAM)
+            message = "Uvicorn running on socket %s (Press CTRL+C to quit)"
+            fd_name_format = "%s"
+            color_message = (
+                "Uvicorn running on "
+                + click.style(fd_name_format, bold=True)
+                + " (Press CTRL+C to quit)"
+            )
+            logger_args = [sock.getsockname()]
+        else:
+            family = socket.AF_INET
+            addr_format = "%s://%s:%d"
+
+            if self.host and ":" in self.host:
+                # It's an IPv6 address.
+                family = socket.AF_INET6
+                addr_format = "%s://[%s]:%d"
+
+            sock = socket.socket(family=family)
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            try:
+                sock.bind((self.host, self.port))
+            except OSError as exc:
+                logger.error(exc)
+                sys.exit(1)
 
-        sock = socket.socket(family=family)
-        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        try:
-            sock.bind((self.host, self.port))
-        except OSError as exc:
-            logger.error(exc)
-            sys.exit(1)
+            message = f"Uvicorn running on {addr_format} (Press CTRL+C to quit)"
+            color_message = (
+                "Uvicorn running on "
+                + click.style(addr_format, bold=True)
+                + " (Press CTRL+C to quit)"
+            )
+            protocol_name = "https" if self.is_ssl else "http"
+            logger_args = [protocol_name, self.host, self.port]
+        logger.info(message, *logger_args, extra={"color_message": color_message})
         sock.set_inheritable(True)
-
-        message = f"Uvicorn running on {addr_format} (Press CTRL+C to quit)"
-        color_message = (
-            "Uvicorn running on "
-            + click.style(addr_format, bold=True)
-            + " (Press CTRL+C to quit)"
-        )
-        protocol_name = "https" if self.is_ssl else "http"
-        logger.info(
-            message,
-            protocol_name,
-            self.host,
-            self.port,
-            extra={"color_message": color_message},
-        )
         return sock
 
     @property

uvicorn/main.py

@@ -1,4 +1,5 @@
 import logging
+import os
 import platform
 import ssl
 import sys
@@ -426,6 +427,8 @@ def run(app: typing.Union[ASGIApplication, str], **kwargs: typing.Any) -> None:
         Multiprocess(config, target=server.run, sockets=[sock]).run()
     else:
         server.run()
+    if config.uds:
+        os.remove(config.uds)
 
 
 if __name__ == "__main__":