add dispatch.serve function

Signed-off-by: Achille Roussel <achille.roussel@gmail.com>

Author: achille-roussel

README.md

@@ -82,7 +82,7 @@ import dispatch
 def greet(msg: str):
     print(f"Hello, ${msg}!")
 
-greet.dispatch('World')
+dispatch.run(lambda: greet.dispatch('World'))
 ```
 
 Obviously, this is just an example, a real application would perform much more

src/dispatch/__init__.py

@@ -4,6 +4,7 @@
 
 import os
 from concurrent import futures
+from contextlib import contextmanager
 from http.server import ThreadingHTTPServer
 from typing import Any, Callable, Coroutine, Optional, TypeVar, overload
 from urllib.parse import urlsplit
@@ -37,6 +38,7 @@
     "gather",
     "race",
     "run",
+    "serve",
 ]
 
 
@@ -46,7 +48,7 @@
 _registry: Optional[Registry] = None
 
 
-def _default_registry():
+def default_registry():
     global _registry
     if not _registry:
         _registry = Registry()
@@ -62,10 +64,10 @@ def function(func: Callable[P, T]) -> Function[P, T]: ...
 
 
 def function(func):
-    return _default_registry().function(func)
+    return default_registry().function(func)
 
 
-def run(port: str = os.environ.get("DISPATCH_ENDPOINT_ADDR", "localhost:8000")):
+def run(init: Callable[P, T], *args: P.args, **kwargs: P.kwargs) -> T:
     """Run the default dispatch server on the given port. The default server
     uses a function registry where functions tagged by the `@dispatch.function`
     decorator are registered.
@@ -75,12 +77,35 @@ def run(port: str = os.environ.get("DISPATCH_ENDPOINT_ADDR", "localhost:8000")):
     to the Dispatch bridge API.
 
     Args:
-        port: The address to bind the server to. Defaults to the value of the
+        entrypoint: The entrypoint function to run. Defaults to a no-op function.
+
+        args: Positional arguments to pass to the entrypoint.
+
+        kwargs: Keyword arguments to pass to the entrypoint.
+
+    Returns:
+        The return value of the entrypoint function.
+    """
+    with serve():
+        return init(*args, **kwargs)
+
+
+@contextmanager
+def serve(address: str = os.environ.get("DISPATCH_ENDPOINT_ADDR", "localhost:8000")):
+    """Returns a context manager managing the operation of a Disaptch server
+    running on the given address. The server is initialized before the context
+    manager yields, then runs forever until the the program is interrupted.
+
+    Args:
+        address: The address to bind the server to. Defaults to the value of the
           DISPATCH_ENDPOINT_ADDR environment variable, or 'localhost:8000' if it
           wasn't set.
     """
-    print(f"Starting Dispatch server on {port}")
-    parsed_url = urlsplit("//" + port)
+    parsed_url = urlsplit("//" + address)
     server_address = (parsed_url.hostname or "", parsed_url.port or 0)
-    server = ThreadingHTTPServer(server_address, Dispatch(_default_registry()))
-    server.serve_forever()
+    server = ThreadingHTTPServer(server_address, Dispatch(default_registry()))
+    try:
+        yield server
+        server.serve_forever()
+    finally:
+        server.server_close()

src/dispatch/http.py

@@ -1,7 +1,5 @@
 """Integration of Dispatch functions with http."""
 
-from datetime import datetime
-
 import logging
 import os
 from datetime import timedelta
@@ -66,9 +64,7 @@ def __init__(
         self.registry = registry
         self.verification_key = verification_key
         self.error_content_type = "application/json"
-        print(datetime.now(), "INITIALIZING FUNCTION SERVICE")
         super().__init__(request, client_address, server)
-        print(datetime.now(), "DONE HANDLING REQUEST")
 
     def send_error_response_invalid_argument(self, message: str):
         self.send_error_response(400, "invalid_argument", message)
@@ -91,9 +87,7 @@ def send_error_response(self, status: int, code: str, message: str):
         self.send_header("Content-Type", self.error_content_type)
         self.send_header("Content-Length", str(len(body)))
         self.end_headers()
-        print(datetime.now(), "SENDING ERROR RESPONSE")
         self.wfile.write(body)
-        print(datetime.now(), f"SERVER IS DONE {len(body)}")
 
     def do_POST(self):
         if self.path != "/dispatch.sdk.v1.FunctionService/Run":
@@ -112,7 +106,6 @@ def do_POST(self):
             return
 
         data: bytes = self.rfile.read(content_length)
-        print(datetime.now(), f"RECEIVED POST REQUEST: {self.path} {len(data)} {self.request_version} {self.headers}")
         logger.debug("handling run request with %d byte body", len(data))
 
         if self.verification_key is not None:
@@ -150,7 +143,6 @@ def do_POST(self):
             )
             return
 
-        print(datetime.now(), "running function '%s'", req.function)
         try:
             output = func._primitive_call(Input(req))
         except Exception:

tests/test_http.py

@@ -57,9 +57,6 @@ def tearDown(self):
         self.server.server_close()
 
     def test_Dispatch_defaults(self):
-        print("POST REQUEST", f"{self.endpoint}/dispatch.sdk.v1.FunctionService/Run")
         resp = self.client.post(f"{self.endpoint}/dispatch.sdk.v1.FunctionService/Run")
-        print(resp.status_code)
-        print("CLIENT RESPONSE!", resp.headers)
-        #body = resp.read()
-        #self.assertEqual(resp.status_code, 400)
+        body = resp.read()
+        self.assertEqual(resp.status_code, 400)