Handle default values correctly

codegen-server/python/src/main/kotlin/software/amazon/smithy/rust/codegen/server/python/smithy/generators/PythonApplicationGenerator.kt

@@ -288,7 +288,7 @@ class PythonApplicationGenerator(
                 /// :param workers ${PythonType.Optional(PythonType.Int).render()}: 
                 /// :param tls ${PythonType.Optional(tlsConfig).render()}:
                 /// :rtype ${PythonType.None.render()}:
-                ##[pyo3(text_signature = "(${'$'}self, address, port, backlog, workers, tls)")]
+                ##[pyo3(text_signature = "(${'$'}self, address=None, port=None, backlog=None, workers=None, tls=None)")]
                 pub fn run(
                     &mut self,
                     py: #{pyo3}::Python,
@@ -315,7 +315,7 @@ class PythonApplicationGenerator(
                 }
 
                 /// Build the service and start a single worker.
-                ##[pyo3(text_signature = "(${'$'}self, socket, worker_number, tls)")]
+                ##[pyo3(text_signature = "(${'$'}self, socket, worker_number, tls=None)")]
                 pub fn start_worker(
                     &mut self,
                     py: pyo3::Python,

rust-runtime/aws-smithy-http-server-python/examples/stubgen.py

@@ -150,8 +150,8 @@ def is_fn_like(obj: Any) -> bool:
     )
 
 
-def walk_field(writer: Writer, name: str, field: Any) -> str:
-    return f"{name}: {writer.fix_and_include(DocstringParser.parse_type(field))} = ..."
+def make_field(writer: Writer, name: str, field: Any) -> str:
+    return f"{name}: {writer.fix_and_include(DocstringParser.parse_type(field))}"
 
 
 def make_function(writer: Writer, name: str, obj: Any, indent_level: int = 0) -> str:
@@ -161,6 +161,13 @@ def make_function(writer: Writer, name: str, obj: Any, indent_level: int = 0) ->
         return f"{name}: {writer.include('typing.Any')}"
 
     params, rtype = res
+    # We're using signature for getting default values only, currently type hints are not supported
+    # in signatures. We can leverage signatures more if it supports type hints in future.
+    sig: Optional[inspect.Signature] = None
+    try:
+        sig = inspect.signature(obj)
+    except:
+        pass
 
     receivers: List[str] = []
     attrs: List[str] = []
@@ -169,9 +176,17 @@ def make_function(writer: Writer, name: str, obj: Any, indent_level: int = 0) ->
     else:
         attrs.append("@staticmethod")
 
-    params = ", ".join(
-        receivers + [f"{n}: {writer.fix_and_include(t)} = ..." for n, t in params]
-    )
+    def format_param(name: str, ty: str) -> str:
+        param = f"{name}: {writer.fix_and_include(ty)}"
+
+        if sig is not None:
+            sig_param = sig.parameters.get(name)
+            if sig_param and sig_param.default is not sig_param.empty:
+                param += f" = {sig_param.default}"
+
+        return param
+
+    params = ", ".join(receivers + [format_param(n, t) for n, t in params])
 
     fn_def = ""
     if len(attrs) > 0:
@@ -194,15 +209,15 @@ def make_class(
         if inspect.isdatadescriptor(member):
             is_empty = False
             definition += (
-                indent(walk_field(writer, name, member), indent_level + 4) + "\n"
+                indent(make_field(writer, name, member), indent_level + 4) + "\n"
             )
         elif is_fn_like(member):
             is_empty = False
             definition += make_function(writer, name, member, indent_level + 4) + "\n"
         # Enum variant
         elif isinstance(member, klass):
             is_empty = False
-            definition += indent(f"{name}: {class_name} = ...\n", indent_level + 4)
+            definition += indent(f"{name}: {class_name}\n", indent_level + 4)
         else:
             print(f"Unknown member type={member}")
 

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

@@ -44,7 +44,7 @@ impl From<PyError> for PyErr {
 /// :param status_code typing.Optional[int]:
 /// :rtype None:
 #[pyclass(name = "MiddlewareException", extends = BasePyException)]
-#[pyo3(text_signature = "(message, status_code)")]
+#[pyo3(text_signature = "($self, message, status_code=None)")]
 #[derive(Debug, Clone)]
 pub struct PyMiddlewareException {
     #[pyo3(get, set)]

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

@@ -91,6 +91,7 @@ fn setup_tracing_subscriber(
 /// :param logfile typing.Optional[pathlib.Path]:
 /// :rtype None:
 #[pyclass(name = "TracingHandler")]
+#[pyo3(text_signature = "($self, level=None, logfile=None)")]
 #[derive(Debug)]
 pub struct PyTracingHandler {
     _guard: Option<WorkerGuard>,

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

@@ -17,7 +17,6 @@ use super::{PyHeaderMap, PyMiddlewareError};
 
 /// Python-compatible [Request] object.
 #[pyclass(name = "Request")]
-#[pyo3(text_signature = "(request)")]
 #[derive(Debug)]
 pub struct PyRequest {
     parts: Option<Parts>,

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

@@ -23,7 +23,7 @@ use super::{PyHeaderMap, PyMiddlewareError};
 /// :param body typing.Optional[bytes]:
 /// :rtype None:
 #[pyclass(name = "Response")]
-#[pyo3(text_signature = "(status, headers, body)")]
+#[pyo3(text_signature = "($self, status, headers=None, body=None)")]
 pub struct PyResponse {
     parts: Option<Parts>,
     headers: PyHeaderMap,

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

@@ -49,7 +49,6 @@ impl PySocket {
 
     /// Clone the inner socket allowing it to be shared between multiple
     /// Python processes.
-    #[pyo3(text_signature = "($self, socket, worker_number)")]
     pub fn try_clone(&self) -> PyResult<PySocket> {
         let copied = self.inner.try_clone()?;
         Ok(PySocket { inner: copied })

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

@@ -27,7 +27,7 @@ pub mod listener;
 /// :rtype None:
 #[pyclass(
     name = "TlsConfig",
-    text_signature = "(*, key_path, cert_path, reload)"
+    text_signature = "($self, *, key_path, cert_path, reload_secs=86400)"
 )]
 #[derive(Clone)]
 pub struct PyTlsConfig {