Add option to prefix config keys in configurable_alts (#13714)

libs/core/Makefile

@@ -13,7 +13,7 @@ tests:
 	poetry run pytest $(TEST_FILE)
 
 test_watch:
-	poetry run ptw --snapshot-update --now . -- -x tests/unit_tests
+	poetry run ptw --snapshot-update --now . -- -vv -x tests/unit_tests
 
 
 ######################

libs/core/langchain_core/runnables/base.py

@@ -1204,15 +1204,21 @@ def configurable_fields(
     def configurable_alternatives(
         self,
         which: ConfigurableField,
+        *,
         default_key: str = "default",
+        prefix_keys: bool = False,
         **kwargs: Union[Runnable[Input, Output], Callable[[], Runnable[Input, Output]]],
     ) -> RunnableSerializable[Input, Output]:
         from langchain_core.runnables.configurable import (
             RunnableConfigurableAlternatives,
         )
 
         return RunnableConfigurableAlternatives(
-            which=which, default=self, alternatives=kwargs, default_key=default_key
+            which=which,
+            default=self,
+            alternatives=kwargs,
+            default_key=default_key,
+            prefix_keys=prefix_keys,
         )
 
 

libs/core/langchain_core/runnables/configurable.py

@@ -220,6 +220,7 @@ def config_specs(self) -> List[ConfigurableFieldSpec]:
                     annotation=spec.annotation
                     or self.default.__fields__[field_name].annotation,
                     default=getattr(self.default, field_name),
+                    is_shared=spec.is_shared,
                 )
                 if isinstance(spec, ConfigurableField)
                 else make_options_spec(
@@ -298,6 +299,12 @@ class RunnableConfigurableAlternatives(DynamicRunnable[Input, Output]):
     ]
 
     default_key: str = "default"
+    """The enum value to use for the default option. Defaults to "default"."""
+
+    prefix_keys: bool
+    """Whether to prefix configurable fields of each alternative with a namespace
+    of the form <which.id>==<alternative_key>, eg. a key named "temperature" used by 
+    the alternative named "gpt3" becomes "model==gpt3/temperature"."""
 
     @property
     def config_specs(self) -> List[ConfigurableFieldSpec]:
@@ -313,21 +320,37 @@ def config_specs(self) -> List[ConfigurableFieldSpec]:
                     ),
                 )
                 _enums_for_spec[self.which] = cast(Type[StrEnum], which_enum)
-        return [
-            ConfigurableFieldSpec(
-                id=self.which.id,
-                name=self.which.name,
-                description=self.which.description,
-                annotation=which_enum,
-                default=self.default_key,
-            ),
-            *self.default.config_specs,
-        ] + [
-            s
-            for alt in self.alternatives.values()
-            if isinstance(alt, RunnableSerializable)
-            for s in alt.config_specs
-        ]
+        return get_unique_config_specs(
+            # which alternative
+            [
+                ConfigurableFieldSpec(
+                    id=self.which.id,
+                    name=self.which.name,
+                    description=self.which.description,
+                    annotation=which_enum,
+                    default=self.default_key,
+                    is_shared=self.which.is_shared,
+                ),
+            ]
+            # config specs of the default option
+            + (
+                [
+                    prefix_config_spec(s, f"{self.which.id}=={self.default_key}")
+                    for s in self.default.config_specs
+                ]
+                if self.prefix_keys
+                else self.default.config_specs
+            )
+            # config specs of the alternatives
+            + [
+                prefix_config_spec(s, f"{self.which.id}=={alt_key}")
+                if self.prefix_keys
+                else s
+                for alt_key, alt in self.alternatives.items()
+                if isinstance(alt, RunnableSerializable)
+                for s in alt.config_specs
+            ]
+        )
 
     def configurable_fields(
         self, **kwargs: AnyConfigurableField
@@ -355,6 +378,23 @@ def _prepare(
             raise ValueError(f"Unknown alternative: {which}")
 
 
+def prefix_config_spec(
+    spec: ConfigurableFieldSpec, prefix: str
+) -> ConfigurableFieldSpec:
+    return (
+        ConfigurableFieldSpec(
+            id=f"{prefix}/{spec.id}",
+            name=spec.name,
+            description=spec.description,
+            annotation=spec.annotation,
+            default=spec.default,
+            is_shared=spec.is_shared,
+        )
+        if not spec.is_shared
+        else spec
+    )
+
+
 def make_options_spec(
     spec: Union[ConfigurableFieldSingleOption, ConfigurableFieldMultiOption],
     description: Optional[str],
@@ -377,6 +417,7 @@ def make_options_spec(
             description=spec.description or description,
             annotation=enum,
             default=spec.default,
+            is_shared=spec.is_shared,
         )
     else:
         return ConfigurableFieldSpec(
@@ -385,4 +426,5 @@ def make_options_spec(
             description=spec.description or description,
             annotation=Sequence[enum],  # type: ignore[valid-type]
             default=spec.default,
+            is_shared=spec.is_shared,
         )

libs/core/langchain_core/runnables/history.py

@@ -169,6 +169,7 @@ def config_specs(self) -> List[ConfigurableFieldSpec]:
                     name="Session ID",
                     description="Unique identifier for a session.",
                     default="",
+                    is_shared=True,
                 ),
             ]
         )

libs/core/langchain_core/runnables/utils.py

@@ -257,6 +257,7 @@ class ConfigurableField(NamedTuple):
     name: Optional[str] = None
     description: Optional[str] = None
     annotation: Optional[Any] = None
+    is_shared: bool = False
 
     def __hash__(self) -> int:
         return hash((self.id, self.annotation))
@@ -271,6 +272,7 @@ class ConfigurableFieldSingleOption(NamedTuple):
 
     name: Optional[str] = None
     description: Optional[str] = None
+    is_shared: bool = False
 
     def __hash__(self) -> int:
         return hash((self.id, tuple(self.options.keys()), self.default))
@@ -285,6 +287,7 @@ class ConfigurableFieldMultiOption(NamedTuple):
 
     name: Optional[str] = None
     description: Optional[str] = None
+    is_shared: bool = False
 
     def __hash__(self) -> int:
         return hash((self.id, tuple(self.options.keys()), tuple(self.default)))
@@ -299,12 +302,13 @@ class ConfigurableFieldSpec(NamedTuple):
     """A field that can be configured by the user. It is a specification of a field."""
 
     id: str
-    name: Optional[str]
-    description: Optional[str]
-
-    default: Any
     annotation: Any
 
+    name: Optional[str] = None
+    description: Optional[str] = None
+    default: Any = None
+    is_shared: bool = False
+
 
 def get_unique_config_specs(
     specs: Iterable[ConfigurableFieldSpec],

libs/core/tests/unit_tests/runnables/test_runnable.py

@@ -1020,6 +1020,118 @@ def test_configurable_alts_factory() -> None:
     assert fake_llm.with_config(configurable={"llm": "chat"}).invoke("...") == "b"
 
 
+def test_configurable_fields_prefix_keys() -> None:
+    fake_chat = FakeListChatModel(responses=["b"]).configurable_fields(
+        responses=ConfigurableFieldMultiOption(
+            id="responses",
+            name="Chat Responses",
+            options={
+                "hello": "A good morning to you!",
+                "bye": "See you later!",
+                "helpful": "How can I help you?",
+            },
+            default=["hello", "bye"],
+        ),
+        # (sleep is a configurable field in FakeListChatModel)
+        sleep=ConfigurableField(
+            id="chat_sleep",
+            is_shared=True,
+        ),
+    )
+    fake_llm = (
+        FakeListLLM(responses=["a"])
+        .configurable_fields(
+            responses=ConfigurableField(
+                id="responses",
+                name="LLM Responses",
+                description="A list of fake responses for this LLM",
+            )
+        )
+        .configurable_alternatives(
+            ConfigurableField(id="llm", name="LLM"),
+            chat=fake_chat | StrOutputParser(),
+            prefix_keys=True,
+        )
+    )
+    prompt = PromptTemplate.from_template("Hello, {name}!").configurable_fields(
+        template=ConfigurableFieldSingleOption(
+            id="prompt_template",
+            name="Prompt Template",
+            description="The prompt template for this chain",
+            options={
+                "hello": "Hello, {name}!",
+                "good_morning": "A very good morning to you, {name}!",
+            },
+            default="hello",
+        )
+    )
+
+    chain = prompt | fake_llm
+
+    assert chain.config_schema().schema() == {
+        "title": "RunnableSequenceConfig",
+        "type": "object",
+        "properties": {"configurable": {"$ref": "#/definitions/Configurable"}},
+        "definitions": {
+            "LLM": {
+                "title": "LLM",
+                "description": "An enumeration.",
+                "enum": ["chat", "default"],
+                "type": "string",
+            },
+            "Chat_Responses": {
+                "title": "Chat Responses",
+                "description": "An enumeration.",
+                "enum": ["hello", "bye", "helpful"],
+                "type": "string",
+            },
+            "Prompt_Template": {
+                "title": "Prompt Template",
+                "description": "An enumeration.",
+                "enum": ["hello", "good_morning"],
+                "type": "string",
+            },
+            "Configurable": {
+                "title": "Configurable",
+                "type": "object",
+                "properties": {
+                    "prompt_template": {
+                        "title": "Prompt Template",
+                        "description": "The prompt template for this chain",
+                        "default": "hello",
+                        "allOf": [{"$ref": "#/definitions/Prompt_Template"}],
+                    },
+                    "llm": {
+                        "title": "LLM",
+                        "default": "default",
+                        "allOf": [{"$ref": "#/definitions/LLM"}],
+                    },
+                    # not prefixed because marked as shared
+                    "chat_sleep": {
+                        "title": "Chat Sleep",
+                        "type": "number",
+                    },
+                    # prefixed for "chat" option
+                    "llm==chat/responses": {
+                        "title": "Chat Responses",
+                        "default": ["hello", "bye"],
+                        "type": "array",
+                        "items": {"$ref": "#/definitions/Chat_Responses"},
+                    },
+                    # prefixed for "default" option
+                    "llm==default/responses": {
+                        "title": "LLM Responses",
+                        "description": "A list of fake responses for this LLM",
+                        "default": ["a"],
+                        "type": "array",
+                        "items": {"type": "string"},
+                    },
+                },
+            },
+        },
+    }
+
+
 def test_configurable_fields_example() -> None:
     fake_chat = FakeListChatModel(responses=["b"]).configurable_fields(
         responses=ConfigurableFieldMultiOption(