add more comments

Signed-off-by: Gene Su <e870252314@gmail.com>
ray-project · edoakes · Dec 8, 2023 · Dec 6, 2023 · Dec 6, 2023 · Dec 6, 2023
commit 308a2bd7953df5d0f332f5c861c8c29c239ebf46
diff --git a/python/ray/serve/_private/proxy.py b/python/ray/serve/_private/proxy.py
@@ -641,7 +641,11 @@ async def unary_unary(
                     response = message
 
             # Only the latest code and details will take effect. If the user already
-            # set them in the context, skip setting them with Serve's default values.
+            # set them to a truthy value in the context, skip setting them with Serve's
+            # default values. By default, if nothing is set, the code is 0 and the
+            # details is "", which both are falsy. So if the user did not set them or
+            # if they're explicitly set to falsy values, such as None, Serve will
+            # continue to set them with our default values.
             if not context.code():
                 context.set_code(status.code)
             if not context.details():
@@ -674,7 +678,11 @@ async def unary_stream(
                     yield message
 
             # Only the latest code and details will take effect. If the user already
-            # set them in the context, skip setting them with Serve's default values.
+            # set them to a truthy value in the context, skip setting them with Serve's
+            # default values. By default, if nothing is set, the code is 0 and the
+            # details is "", which both are falsy. So if the user did not set them or
+            # if they're explicitly set to falsy values, such as None, Serve will
+            # continue to set them with our default values.
             if not context.code():
                 context.set_code(status.code)
             if not context.details():

diff --git a/python/ray/serve/_private/proxy_request_response.py b/python/ray/serve/_private/proxy_request_response.py
@@ -120,6 +120,8 @@ def __init__(
         self.request_id = None
         self.method_name = "__call__"
         self.multiplexed_model_id = DEFAULT.VALUE
+        # ray_serve_grpc_context is a class implemented by us to be able to serialize
+        # the object and pass into the deployment.
         self.ray_serve_grpc_context = RayServegRPCContext(context)
         self.setup_variables()
 
@@ -161,6 +163,9 @@ def user_request(self) -> bytes:
         return self.request
 
     def send_request_id(self, request_id: str):
+        # Setting the trailing metadata on the ray_serve_grpc_context object, so it's
+        # not overriding the ones set from the user and will be sent back to the
+        # client altogether.
         self.ray_serve_grpc_context.set_trailing_metadata([("request_id", request_id)])
 
     def request_object(self, proxy_handle: ActorHandle) -> gRPCRequest:

diff --git a/python/ray/serve/_private/router.py b/python/ray/serve/_private/router.py
@@ -65,6 +65,7 @@ class RequestMetadata:
     # The protocol to serve this request
     _request_protocol: RequestProtocol = RequestProtocol.UNDEFINED
 
+    # Serve's gRPC context associated with this request for getting and setting metadata
     grpc_context: Optional[RayServegRPCContext] = None
 
     @property