chore: import upstream snapshot with attribution

doc/source/serve/doc_code/model_composition/language_example.py

@@ -0,0 +1,98 @@
+# flake8: noqa
+
+import requests
+
+# __echo_class_start__
+# File name: echo.py
+from starlette.requests import Request
+
+from ray import serve
+
+
+@serve.deployment
+class EchoClass:
+    def __init__(self, echo_str: str):
+        self.echo_str = echo_str
+
+    def __call__(self, request: Request) -> str:
+        return self.echo_str
+
+
+# You can create ClassNodes from the EchoClass deployment
+foo_node = EchoClass.bind("foo")
+bar_node = EchoClass.bind("bar")
+baz_node = EchoClass.bind("baz")
+# __echo_class_end__
+
+for node, echo in [(foo_node, "foo"), (bar_node, "bar"), (baz_node, "baz")]:
+    serve.run(node)
+    assert requests.get("http://localhost:8000/").text == echo
+
+# __echo_client_start__
+# File name: echo_client.py
+import requests
+
+response = requests.get("http://localhost:8000/")
+echo = response.text
+print(echo)
+# __echo_client_end__
+
+# __hello_start__
+# File name: hello.py
+from ray import serve
+from ray.serve.handle import DeploymentHandle
+
+
+@serve.deployment
+class LanguageClassifer:
+    def __init__(
+        self, spanish_responder: DeploymentHandle, french_responder: DeploymentHandle
+    ):
+        self.spanish_responder = spanish_responder
+        self.french_responder = french_responder
+
+    async def __call__(self, http_request):
+        request = await http_request.json()
+        language, name = request["language"], request["name"]
+
+        if language == "spanish":
+            response = self.spanish_responder.say_hello.remote(name)
+        elif language == "french":
+            response = self.french_responder.say_hello.remote(name)
+        else:
+            return "Please try again."
+
+        return await response
+
+
+@serve.deployment
+class SpanishResponder:
+    def say_hello(self, name: str):
+        return f"Hola {name}"
+
+
+@serve.deployment
+class FrenchResponder:
+    def say_hello(self, name: str):
+        return f"Bonjour {name}"
+
+
+spanish_responder = SpanishResponder.bind()
+french_responder = FrenchResponder.bind()
+language_classifier = LanguageClassifer.bind(spanish_responder, french_responder)
+# __hello_end__
+
+serve.run(language_classifier)
+
+# __hello_client_start__
+# File name: hello_client.py
+import requests
+
+response = requests.post(
+    "http://localhost:8000", json={"language": "spanish", "name": "Dora"}
+)
+greeting = response.text
+print(greeting)
+# __hello_client_end__
+
+assert greeting == "Hola Dora"