Add a ready trigger callback

src/hypercorn/asyncio/__init__.py

@@ -4,7 +4,7 @@
 from typing import Awaitable, Callable, Literal, Optional
 
 from .run import worker_serve
-from ..config import Config
+from ..config import Config, Sockets
 from ..typing import Framework
 from ..utils import wrap_app
 
@@ -15,6 +15,7 @@ async def serve(
     *,
     shutdown_trigger: Optional[Callable[..., Awaitable]] = None,
     mode: Optional[Literal["asgi", "wsgi"]] = None,
+    ready_trigger: Optional[Callable[[Sockets], None]] = None,
 ) -> None:
     """Serve an ASGI or WSGI framework app given the config.
 
@@ -34,6 +35,8 @@ async def serve(
         config: A Hypercorn configuration object.
         shutdown_trigger: This should return to trigger a graceful
             shutdown.
+        ready_trigger: This is called when it is ready to accept
+            connections.
         mode: Specify if the app is WSGI or ASGI.
     """
     if config.debug:
@@ -42,5 +45,5 @@ async def serve(
         warnings.warn("The config `workers` has no affect when using serve", Warning)
 
     await worker_serve(
-        wrap_app(app, config.wsgi_max_body_size, mode), config, shutdown_trigger=shutdown_trigger
+        wrap_app(app, config.wsgi_max_body_size, mode), config, shutdown_trigger=shutdown_trigger, ready_trigger=ready_trigger,
     )

src/hypercorn/asyncio/run.py

@@ -56,6 +56,7 @@ async def worker_serve(
     *,
     sockets: Optional[Sockets] = None,
     shutdown_trigger: Optional[Callable[..., Awaitable]] = None,
+    ready_trigger: Optional[Callable[[Sockets], None]] = None
 ) -> None:
     config.set_statsd_logger_class(StatsdLogger)
 
@@ -77,6 +78,11 @@ def _signal_handler(*_: Any) -> None:  # noqa: N803
 
         shutdown_trigger = signal_event.wait
 
+    if ready_trigger is None:
+        def _ready_trigger(sockets: Sockets) -> None:
+            pass
+        ready_trigger = _ready_trigger
+
     lifespan_state: LifespanState = {}
     lifespan = Lifespan(app, config, loop, lifespan_state)
 
@@ -149,6 +155,8 @@ async def _server_callback(reader: asyncio.StreamReader, writer: asyncio.StreamW
         bind = repr_socket_addr(sock.family, sock.getsockname())
         await config.log.info(f"Running on https://{bind} (QUIC) (CTRL + C to quit)")
 
+    ready_trigger(sockets)
+
     try:
         async with TaskGroup() as task_group:
             task_group.create_task(raise_shutdown(shutdown_trigger))