feat: supports setting multiple hosts

docs/deployment.md

@@ -31,8 +31,7 @@ $ uvicorn --help
 Usage: uvicorn [OPTIONS] APP
 
 Options:
-  --host TEXT                     Bind socket to this host.  [default:
-                                  127.0.0.1]
+  --host TEXT                     Bind socket to this host.
   --port INTEGER                  Bind socket to this port. If 0, an available
                                   port will be picked.  [default: 8000]
   --uds TEXT                      Bind to a UNIX domain socket.

docs/index.md

@@ -101,8 +101,7 @@ $ uvicorn --help
 Usage: uvicorn [OPTIONS] APP
 
 Options:
-  --host TEXT                     Bind socket to this host.  [default:
-                                  127.0.0.1]
+  --host TEXT                     Bind socket to this host.
   --port INTEGER                  Bind socket to this port. If 0, an available
                                   port will be picked.  [default: 8000]
   --uds TEXT                      Bind to a UNIX domain socket.

docs/settings.md

@@ -22,8 +22,7 @@ For example, in case you want to run the app on port `5000`, just set the enviro
 
 ## Socket Binding
 
-* `--host <str>` - Bind socket to this host. Use `--host 0.0.0.0` to make the application available on your local network. IPv6 addresses are supported, for example: `--host '::'`. **Default:** *'127.0.0.1'*.
-* `--port <int>` - Bind to a socket with this port. **Default:** *8000*.
+* `--host <str>` - Bind socket to this host. May be used multiple times. If unused, then by default 127.0.0.1. IPv6 addresses are supported, for example: `--host '::'`, when using ipv6 only, if ipv4 is available it will work at the same time.
 * `--uds <path>` - Bind to a UNIX domain socket, for example `--uds /tmp/uvicorn.sock`. Useful if you want to run Uvicorn behind a reverse proxy.
 * `--fd <int>` - Bind to socket from this file descriptor. Useful if you want to run Uvicorn within a process manager.
 

tests/test_config.py

@@ -262,9 +262,10 @@ def test_concrete_http_class() -> None:
 def test_socket_bind() -> None:
     config = Config(app=asgi_app)
     config.load()
-    sock = config.bind_socket()
-    assert isinstance(sock, socket.socket)
-    sock.close()
+    sockets = config.bind_socket()
+    for sock in sockets:
+        assert isinstance(sock, socket.socket)
+        sock.close()
 
 
 def test_ssl_config(
@@ -493,11 +494,12 @@ def test_bind_unix_socket_works_with_reload_or_workers(
 ):  # pragma: py-win32
     config = Config(app=asgi_app, uds=short_socket_name, reload=reload, workers=workers)
     config.load()
-    sock = config.bind_socket()
-    assert isinstance(sock, socket.socket)
-    assert sock.family == socket.AF_UNIX
-    assert sock.getsockname() == short_socket_name
-    sock.close()
+    sockets = config.bind_socket()
+    for sock in sockets:
+        assert isinstance(sock, socket.socket)
+        assert sock.family == socket.AF_UNIX
+        assert sock.getsockname() == short_socket_name
+        sock.close()
 
 
 @pytest.mark.parametrize(
@@ -514,12 +516,13 @@ def test_bind_fd_works_with_reload_or_workers(reload: bool, workers: int):  # pr
     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()
+    sockets = config.bind_socket()
+    for sock in sockets:
+        assert isinstance(sock, socket.socket)
+        assert sock.family == socket.AF_UNIX
+        assert sock.getsockname() == ""
+        sock.close()
+        fdsock.close()
 
 
 @pytest.mark.parametrize(

uvicorn/config.py

@@ -176,7 +176,7 @@ class Config:
     def __init__(
         self,
         app: ASGIApplication | Callable[..., Any] | str,
-        host: str = "127.0.0.1",
+        host: list[str] | str = "127.0.0.1",
         port: int = 8000,
         uds: str | None = None,
         fd: int | None = None,
@@ -225,6 +225,8 @@ def __init__(
         h11_max_incomplete_event_size: int | None = None,
     ):
         self.app = app
+        if host and isinstance(host, str):
+            host = [host]
         self.host = host
         self.port = port
         self.uds = uds
@@ -476,7 +478,8 @@ def setup_event_loop(self) -> None:
         if loop_setup is not None:
             loop_setup(use_subprocess=self.use_subprocess)
 
-    def bind_socket(self) -> socket.socket:
+    def bind_socket(self) -> list[socket.socket]:
+        sockets: list[socket.socket] = []
         logger_args: list[str | int]
         if self.uds:  # pragma: py-win32
             path = self.uds
@@ -489,40 +492,46 @@ def bind_socket(self) -> socket.socket:
                 logger.error(exc)
                 sys.exit(1)
 
+            sockets.append(sock)
             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]
+            logger.info(message, *logger_args, extra={"color_message": color_message})
         elif self.fd:  # pragma: py-win32
             sock = socket.fromfd(self.fd, socket.AF_UNIX, socket.SOCK_STREAM)
+            sockets.append(sock)
             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()]
+            logger.info(message, *logger_args, extra={"color_message": color_message})
         else:
-            family = socket.AF_INET
-            addr_format = "%s://%s:%d"
-
-            if self.host and ":" in self.host:  # pragma: full coverage
-                # 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:  # pragma: full coverage
-                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, sock.getsockname()[1]]
-        logger.info(message, *logger_args, extra={"color_message": color_message})
-        sock.set_inheritable(True)
-        return sock
+            for host in self.host:
+                family = socket.AF_INET
+                addr_format = "%s://%s:%d"
+
+                if ":" in host:  # pragma: full coverage
+                    # 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((host, self.port))
+                except OSError as exc:  # pragma: full coverage
+                    logger.error(exc)
+                    sys.exit(1)
+                sockets.append(sock)
+                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, host, sock.getsockname()[1]]
+                logger.info(message, *logger_args, extra={"color_message": color_message})
+        for sock in sockets:
+            sock.set_inheritable(True)
+        return sockets
 
     @property
     def should_reload(self) -> bool:

uvicorn/main.py

@@ -62,10 +62,11 @@ def print_version(ctx: click.Context, param: click.Parameter, value: bool) -> No
 @click.argument("app", envvar="UVICORN_APP")
 @click.option(
     "--host",
-    type=str,
-    default="127.0.0.1",
+    multiple=True,
     help="Bind socket to this host.",
-    show_default=True,
+    default=[
+        "127.0.0.1",
+    ],
 )
 @click.option(
     "--port",
@@ -362,7 +363,7 @@ def print_version(ctx: click.Context, param: click.Parameter, value: bool) -> No
 )
 def main(
     app: str,
-    host: str,
+    host: list[str],
     port: int,
     uds: str,
     fd: int,
@@ -463,7 +464,7 @@ def main(
 def run(
     app: ASGIApplication | Callable[..., Any] | str,
     *,
-    host: str = "127.0.0.1",
+    host: list[str] | str = "127.0.0.1",
     port: int = 8000,
     uds: str | None = None,
     fd: int | None = None,
@@ -570,11 +571,11 @@ def run(
 
     try:
         if config.should_reload:
-            sock = config.bind_socket()
-            ChangeReload(config, target=server.run, sockets=[sock]).run()
+            sockets = config.bind_socket()
+            ChangeReload(config, target=server.run, sockets=sockets).run()
         elif config.workers > 1:
-            sock = config.bind_socket()
-            Multiprocess(config, target=server.run, sockets=[sock]).run()
+            sockets = config.bind_socket()
+            Multiprocess(config, target=server.run, sockets=sockets).run()
         else:
             server.run()
     except KeyboardInterrupt:

uvicorn/server.py

@@ -198,26 +198,26 @@ def _log_started_message(self, listeners: Sequence[socket.SocketType]) -> None:
             logger.info("Uvicorn running on unix socket %s (Press CTRL+C to quit)", config.uds)
 
         else:
-            addr_format = "%s://%s:%d"
-            host = "0.0.0.0" if config.host is None else config.host
-            if ":" in host:
-                # It's an IPv6 address.
-                addr_format = "%s://[%s]:%d"
-
-            port = config.port
-            if port == 0:
-                port = listeners[0].getsockname()[1]
-
-            protocol_name = "https" if config.ssl else "http"
-            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)"
-            logger.info(
-                message,
-                protocol_name,
-                host,
-                port,
-                extra={"color_message": color_message},
-            )
+            for host in config.host:
+                addr_format = "%s://%s:%d"
+                if ":" in host:
+                    # It's an IPv6 address.
+                    addr_format = "%s://[%s]:%d"
+
+                port = config.port
+                if port == 0:
+                    port = listeners[0].getsockname()[1]
+
+                protocol_name = "https" if config.ssl else "http"
+                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)"
+                logger.info(
+                    message,
+                    protocol_name,
+                    host,
+                    port,
+                    extra={"color_message": color_message},
+                )
 
     async def main_loop(self) -> None:
         counter = 0