Lm based router

Defines a router that utilizes a language model to route the input source to the appropriate path.

LMBasedRouter(lm_request_processor, default_route, valid_routes, lm_output_key=DEFAULT_LM_OUTPUT_KEY)

Bases: BaseRouter, UsesLM

A router that utilizes a language model to determine the appropriate route for an input source.

This class routes a given input source to an appropriate path based on the output of a language model. If the determined route is not valid, it defaults to a predefined route.

The router delegates routing logic to a pluggable backend adapter (e.g., NativeLMBasedAdapter).

Attributes:

Name	Type	Description
backend	BaseAdapter	The backend implementation handling routing logic.
lm_request_processor	LMRequestProcessor	The request processor that handles requests to the language model.
default_route	str	The default route to be used if the language model's output is invalid.
valid_routes	set[str]	A set of valid routes for the router.
lm_output_key	str	The key in the language model's output that contains the route.

Notes

The lm_request_processor must be configured to: 1. Take a "source" key as input. The input source of the router should be passed as the value of this "source" key. 2. Return a JSON object which contains the selected route as a string. The key of the route is specified by the lm_output_key attribute. Furthermore, the selected route must be present in the valid_routes set.

Output example, assuming the lm_output_key is "route": { "route": "" }

Initializes a new instance of the LMBasedRouter class.

Parameters:

Name	Type	Description	Default
lm_request_processor	LMRequestProcessor	The request processor that handles requests to the language model.	required
default_route	str	The default route to be used if the language model's output is invalid.	required
valid_routes	set[str]	A set of valid routes for the router.	required
lm_output_key	str	The key in the language model's output that contains the route. Defaults to DEFAULT_LM_OUTPUT_KEY.	DEFAULT_LM_OUTPUT_KEY

Raises:

Type	Description
ValueError	If the provided default route is not in the set of valid routes.

from_preset(modality, preset_kwargs=None, **kwargs) classmethod

Initialize the LM based router component using preset model configurations.

Examples:

router = LMBasedRouter.from_preset(modality="image")
router = LMBasedRouter.from_preset(
    modality="image",
    preset_kwargs={"default_route": "custom_route", "valid_routes": {"custom_route", "other"}}
)

Parameters:

Name	Type	Description	Default
modality	str	Type of modality input (e.g., "image").	required
preset_kwargs	LMBasedRouterPresetKwargs | dict[str, Any] | None	Additional kwargs for the preset. Can be provided as a dict or as an LMBasedRouterPresetKwargs instance. When provided as a dict, unknown keys will raise a ValidationError. Defaults to None. The following keys are allowed: 1. lm_invoker_kwargs: Configuration for the language model invoker. 2. prompt_builder_kwargs: Configuration for the prompt builder. 3. lm_output_key: The key in the language model's output that contains the route. 4. default_route: Default route to use if LM cannot determine route. 5. valid_routes: Set of valid routes for the router.	None
**kwargs	Any	Additional arguments to pass for this class.	{}

Returns:

Name	Type	Description
LMBasedRouter	LMBasedRouter	Initialized LM-based router component using preset model.

native(lm_request_processor, default_route, valid_routes, lm_output_key=DEFAULT_LM_OUTPUT_KEY) classmethod

Create LM-based router with native backend.

This is a convenience classmethod that creates an LMBasedRouter with a NativeLMBasedAdapter.

Parameters:

Name	Type	Description	Default
lm_request_processor	LMRequestProcessor	The request processor that handles requests to the language model.	required
default_route	str	The default route to be used if the language model's output is invalid.	required
valid_routes	set[str]	A set of valid routes for the router.	required
lm_output_key	str	The key in the language model's output that contains the route. Defaults to DEFAULT_LM_OUTPUT_KEY.	DEFAULT_LM_OUTPUT_KEY

Returns:

Name	Type	Description
LMBasedRouter	LMBasedRouter	Initialized router with native backend.

LMBasedRouterPresetKwargs

Bases: BaseModel

Schema for LMBasedRouter.from_preset preset_kwargs.

This model validates and documents the allowed parameters for the preset configuration.

Attributes:

Name	Type	Description
lm_invoker_kwargs	dict[str, Any] | None	Configuration for the language model invoker.
prompt_builder_kwargs	dict[str, Any] | None	Configuration for the prompt builder.
lm_output_key	str	The key in the language model's output that contains the route.
default_route	str	Default route to use if LM cannot determine route.
valid_routes	set[str]	Set of valid routes for the router.