feat: add multiple handlers server (#32)

* feat: add multiple handlers server

* fix: missing relative_url to root

* fix: update CHANGELOG.md

Co-authored-by: Simon Shillaker <554768+Shillaker@users.noreply.github.com>

---------

Co-authored-by: Simon Shillaker <554768+Shillaker@users.noreply.github.com>

CHANGELOG.md

@@ -22,3 +22,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Update README with link to Serverless Functions Node
+
+## [0.2.0] - 2023-04-23
+
+### Added
+
+- Added a simple server to test with multiple handlers

examples/multiple_handlers.py

@@ -0,0 +1,29 @@
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    # Doing a conditional import avoids the need to install the library
+    # when deploying the function
+    from scaleway_functions_python.framework.v1.hints import Context, Event, Response
+
+
+def hello(_event: "Event", _context: "Context") -> "Response":
+    """Say hello!"""
+    return {"body": "hello"}
+
+
+def world(_event: "Event", _context: "Context") -> "Response":
+    """Say world!"""
+    return {"body": "world"}
+
+
+if __name__ == "__main__":
+    from scaleway_functions_python import local
+
+    server = local.LocalFunctionServer()
+    server.add_handler(hello)
+    server.add_handler(world)
+    server.serve(port=8080)
+
+    # Functions can be queried with:
+    # curl localhost:8080/hello
+    # curl localhost:8080/world

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "scaleway-functions-python"
-version = "0.1.1"
+version = "0.2.0"
 description = "Utilities for testing your Python handlers for Scaleway Serverless Functions."
 authors = ["Scaleway Serverless Team <opensource@scaleway.com>"]
 

scaleway_functions_python/__init__.py

@@ -1,3 +1,4 @@
 from . import local as local
 from .framework import v1 as v1
+from .local.serving import LocalFunctionServer as LocalFunctionServer
 from .local.serving import serve_handler as serve_handler

scaleway_functions_python/local/__init__.py

@@ -1 +1,2 @@
+from .serving import LocalFunctionServer as LocalFunctionServer
 from .serving import serve_handler as serve_handler

scaleway_functions_python/local/serving.py

@@ -1,7 +1,7 @@
 import logging
 from base64 import b64decode
 from json import JSONDecodeError
-from typing import TYPE_CHECKING, Any, ClassVar, cast
+from typing import TYPE_CHECKING, Any, ClassVar, List, Optional, cast
 
 from flask import Flask, json, jsonify, make_response, request
 from flask.views import View
@@ -18,7 +18,7 @@
 
 # TODO?: Switch to https://docs.python.org/3/library/http.html#http-methods
 # for Python 3.11+
-HTTP_METHODS = [
+ALL_HTTP_METHODS = [
     "GET",
     "HEAD",
     "POST",
@@ -144,17 +144,57 @@ def resp_record_to_flask_response(
         return resp
 
 
-def _create_flask_app(handler: "hints.Handler") -> Flask:
-    app = Flask(f"serverless_local_{handler.__name__}")
+class LocalFunctionServer:
+    """LocalFunctionServer serves Scaleway FaaS handlers on a local http server."""
 
-    # Create the view from the handler
-    view = HandlerWrapper(handler).as_view(handler.__name__, handler)
+    def __init__(self) -> None:
+        self.app = Flask("serverless_local")
 
-    # By default, methods contains ["GET", "HEAD", "OPTIONS"]
-    app.add_url_rule("/<path:path>", methods=HTTP_METHODS, view_func=view)
-    app.add_url_rule("/", methods=HTTP_METHODS, defaults={"path": ""}, view_func=view)
+    def add_handler(
+        self,
+        handler: "hints.Handler",
+        relative_url: Optional[str] = None,
+        http_methods: Optional[List[str]] = None,
+    ) -> "LocalFunctionServer":
+        """Add a handler to be served by the server.
 
-    return app
+        :param handler: serverless python handler
+        :param relative_url: path to the handler, defaults to / + handler's name
+        :param http_methods: HTTP methods for the handler, defaults to all methods
+        """
+        relative_url = relative_url if relative_url else "/" + handler.__name__
+        if not relative_url.startswith("/"):
+            relative_url = "/" + relative_url
+
+        http_methods = http_methods if http_methods else ALL_HTTP_METHODS
+        http_methods = [method.upper() for method in http_methods]
+
+        view = HandlerWrapper(handler).as_view(handler.__name__, handler)
+
+        # By default, methods contains ["GET", "HEAD", "OPTIONS"]
+        self.app.add_url_rule(
+            f"{relative_url}/<path:path>", methods=http_methods, view_func=view
+        )
+        self.app.add_url_rule(
+            relative_url,
+            methods=http_methods,
+            defaults={"path": ""},
+            view_func=view,
+        )
+
+        return self
+
+    def serve(
+        self, *args: Any, port: int = 8080, debug: bool = True, **kwargs: Any
+    ) -> None:
+        """Serve the added FaaS handlers.
+
+        :param port: port that the server should listen on, defaults to 8080
+        :param debug: run Flask in debug mode, enables hot-reloading and stack trace.
+        """
+        kwargs["port"] = port
+        kwargs["debug"] = debug
+        self.app.run(*args, **kwargs)
 
 
 def serve_handler(
@@ -175,7 +215,6 @@ def serve_handler(
         ...     return {"body": event["httpMethod"]}
         >>> serve_handler_locally(handle, port=8080)
     """
-    app: Flask = _create_flask_app(handler)
-    kwargs["port"] = port
-    kwargs["debug"] = debug
-    app.run(*args, **kwargs)
+    server = LocalFunctionServer()
+    server.add_handler(handler=handler, relative_url="/")
+    server.serve(*args, port=port, debug=debug, **kwargs)

tests/test_local/test_serving.py

@@ -4,16 +4,17 @@
 import pytest
 from flask.testing import FlaskClient
 
-from scaleway_functions_python.local.serving import _create_flask_app
+from scaleway_functions_python.local.serving import LocalFunctionServer
 
 from .. import handlers as h
 
 
 @pytest.fixture(scope="function")
 def client(request) -> FlaskClient:
-    app = _create_flask_app(request.param)
-    app.config.update({"TESTING": True})
-    return app.test_client()
+    server = LocalFunctionServer()
+    server.add_handler(handler=request.param, relative_url="/")
+    server.app.config.update({"TESTING": True})
+    return server.app.test_client()
 
 
 @pytest.mark.parametrize(
@@ -89,3 +90,33 @@ def test_serve_handler_inject_infra_headers(client):
     assert headers["X-Forwarded-Proto"] == "http"
 
     uuid.UUID(headers["X-Request-Id"])
+
+
+def test_local_function_server_multiple_routes():
+    # Setup a server with two handlers
+    server = LocalFunctionServer()
+    server.add_handler(
+        handler=h.handler_that_returns_string,
+        relative_url="/message",
+        http_methods=["GET"],  # type: ignore
+    )
+    server.add_handler(
+        handler=h.handler_returns_exception,
+        relative_url="kaboom",
+        http_methods=["POST", "PUT"],  # type: ignore
+    )  # type: ignore
+    server.app.config.update({"TESTING": True})
+    client = server.app.test_client()
+
+    resp = client.get("/message")
+    assert resp.text == h.HELLO_WORLD
+
+    resp = client.post("/message")
+    assert resp.status_code == 405  # Method not allowed
+
+    resp = client.get("/kaboom")
+    assert resp.status_code == 405
+
+    with pytest.raises(Exception) as e:
+        client.put("/kaboom")
+        assert str(e) == h.EXCEPTION_MESSAGE