Allow to build and test on MacOX M1/x86 chips (#1609)

* Allow to build and test on MacOX M1 chips

* Add MacOS linker config

* Fall back to standard event loop if uvloop is not available

rust-runtime/aws-smithy-http-server-python/examples/.cargo/config.toml

@@ -0,0 +1,12 @@
+# See: https://pyo3.rs/latest/building_and_distribution.html?highlight=rustflags#macos
+[target.x86_64-apple-darwin]
+rustflags = [
+  "-C", "link-arg=-undefined",
+  "-C", "link-arg=dynamic_lookup",
+]
+
+[target.aarch64-apple-darwin]
+rustflags = [
+  "-C", "link-arg=-undefined",
+  "-C", "link-arg=dynamic_lookup",
+]

rust-runtime/aws-smithy-http-server-python/examples/Makefile

@@ -1,3 +1,4 @@
+OS := $(shell uname -s)
 SRC_DIR := $(shell git rev-parse --show-toplevel)
 CUR_DIR := $(shell pwd)
 GRADLE := $(SRC_DIR)/gradlew
@@ -5,8 +6,15 @@ SERVER_SDK_DST := $(CUR_DIR)/pokemon-service-server-sdk
 CLIENT_SDK_DST := $(CUR_DIR)/pokemon-service-client
 SERVER_SDK_SRC := $(SRC_DIR)/codegen-server-test/python/build/smithyprojections/codegen-server-test-python/pokemon-service-server-sdk/rust-server-codegen-python
 CLIENT_SDK_SRC := $(SRC_DIR)/codegen-test/build/smithyprojections/codegen-test/pokemon-service-client/rust-codegen
-DEBUG_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/debug/libpokemon_service_server_sdk.so
-RELEASE_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/release/libpokemon_service_server_sdk.so
+
+SHARED_LIBRARY_DST := $(CUR_DIR)/libpokemon_service_server_sdk.so
+ifeq ($(OS), Darwin)
+	DEBUG_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/debug/libpokemon_service_server_sdk.dylib
+	RELEASE_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/release/libpokemon_service_server_sdk.dylib
+else
+	DEBUG_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/debug/libpokemon_service_server_sdk.so
+	RELEASE_SHARED_LIBRARY_SRC := $(SRC_DIR)/target/release/libpokemon_service_server_sdk.so
+endif
 
 all: codegen
 
@@ -18,11 +26,11 @@ codegen:
 
 build: codegen
 	cargo build
-	ln -sf $(DEBUG_SHARED_LIBRARY_SRC) $(CUR_DIR)/libpokemon_service_server_sdk.so
+	ln -sf $(DEBUG_SHARED_LIBRARY_SRC) $(SHARED_LIBRARY_DST)
 
 release: codegen
 	cargo build --release
-	ln -sf $(RELEASE_SHARED_LIBRARY_SRC) $(CUR_DIR)/libpokemon_service_server_sdk.so
+	ln -sf $(RELEASE_SHARED_LIBRARY_SRC) $(SHARED_LIBRARY_DST)
 
 run: build
 	python $(CUR_DIR)/pokemon_service.py
@@ -37,6 +45,6 @@ clean:
 	cargo clean || echo "Unable to run cargo clean"
 
 distclean: clean
-	rm -rf $(SERVER_SDK_DST) $(CLIENT_SDK_DST) $(CUR_DIR)/Cargo.lock $(CUR_DIR)/libpokemon_service_server_sdk.so
+	rm -rf $(SERVER_SDK_DST) $(CLIENT_SDK_DST) $(CUR_DIR)/Cargo.lock $(SHARED_LIBRARY_DST)
 
 .PHONY: all

rust-runtime/aws-smithy-http-server-python/examples/README.md

@@ -18,6 +18,27 @@ can be used directly.
 
 `make distclean` can be used for a complete cleanup of all artefacts.
 
+### Uvloop
+
+The server can depend on [uvloop](https://pypi.org/project/uvloop/) for a
+faster event loop implementation. Uvloop can be installed with your favourite
+package manager or by using pip:
+
+```sh
+pip instal uvloop
+```
+
+and it will be automatically used instead of the standard library event loop if
+it is found in the dependencies' closure.
+
+### MacOs
+
+To compile and test on MacOs, please follow the official PyO3 guidelines on how
+to [configure your linker](https://pyo3.rs/latest/building_and_distribution.html?highlight=rustflags#macos).
+
+Please note that the `.cargo/config.toml` with linkers override can be local to
+your project.
+
 ## Run
 
 `cargo run` can be used to start the Pokémon service on

rust-runtime/aws-smithy-http-server-python/src/server.rs

@@ -178,7 +178,9 @@ impl PyApp {
     /// Python asynchronous loop needs to be started and handled during the lifetime of the process.
     /// First of all we install [uvloop] as the main Python event loop. Thanks to libuv, uvloop
     /// performs ~20% better than Python standard event loop in most benchmarks, while being 100%
-    /// compatible.
+    /// compatible. If [uvloop] is not available as a dependency, we just fall back to the standard
+    /// Python event loop.
+    ///
     /// We retrieve the Python context object, if setup by the user calling [PyApp::context] method,
     /// generate the [PyState] structure and build the [aws_smithy_http_server::Router], filling
     /// it with the functions generated by `PythonServerOperationHandlerGenerator.kt`.
@@ -198,10 +200,18 @@ impl PyApp {
         worker_number: isize,
     ) -> PyResult<()> {
         // Setup the Python asyncio loop to use `uvloop`.
+        // If uvloop is not available as a dependency, the standard Python
+        // event loop will be used instead.
         let asyncio = py.import("asyncio")?;
-        let uvloop = py.import("uvloop")?;
-        uvloop.call_method0("install")?;
-        tracing::debug!("Setting up uvloop for current process");
+        match py.import("uvloop") {
+            Ok(uvloop) => {
+                uvloop.call_method0("install")?;
+                tracing::debug!("Setting up uvloop for current process");
+            }
+            Err(_) => {
+                tracing::warn!("Uvloop not found, using Python standard event loop, which could have worse performance than uvloop");
+            }
+        }
         let event_loop = asyncio.call_method0("new_event_loop")?;
         asyncio.call_method1("set_event_loop", (event_loop,))?;
         // Create the `PyState` object from the Python context object.
@@ -309,6 +319,16 @@ impl PyApp {
         let mp = py.import("multiprocessing")?;
         // https://github.com/python/cpython/blob/f4c03484da59049eb62a9bf7777b963e2267d187/Lib/multiprocessing/context.py#L164
         mp.call_method0("allow_connection_pickling")?;
+
+        // Starting from Python 3.8, on macOS, the spawn start method is now the default. See bpo-33725.
+        // This forces the `PyApp` class to be pickled when it is shared between different process,
+        // which is currently not supported by PyO3 classes.
+        //
+        // Forcing the multiprocessing start method to fork is a workaround for it.
+        // https://github.com/pytest-dev/pytest-flask/issues/104#issuecomment-577908228
+        #[cfg(target_os = "macos")]
+        mp.call_method1("set_start_method", ("fork",))?;
+
         let address = address.unwrap_or_else(|| String::from("127.0.0.1"));
         let port = port.unwrap_or(13734);
         let socket = PySocket::new(address, port, backlog)?;