from __future__ import annotations
import enum
import threading
from abc import abstractmethod
from typing import (
Any,
AsyncIterator,
Callable,
Dict,
Iterator,
List,
Optional,
Sequence,
Tuple,
Type,
Union,
cast,
)
from weakref import WeakValueDictionary
from langchain_core.pydantic_v1 import BaseModel
from langchain_core.runnables.base import Runnable, RunnableSerializable
from langchain_core.runnables.config import (
RunnableConfig,
ensure_config,
get_config_list,
get_executor_for_config,
)
from langchain_core.runnables.graph import Graph
from langchain_core.runnables.utils import (
AnyConfigurableField,
ConfigurableField,
ConfigurableFieldMultiOption,
ConfigurableFieldSingleOption,
ConfigurableFieldSpec,
Input,
Output,
gather_with_concurrency,
get_unique_config_specs,
)
[docs]class DynamicRunnable(RunnableSerializable[Input, Output]):
"""A Serializable Runnable that can be dynamically configured."""
default: RunnableSerializable[Input, Output]
class Config:
arbitrary_types_allowed = True
[docs] @classmethod
def is_lc_serializable(cls) -> bool:
return True
[docs] @classmethod
def get_lc_namespace(cls) -> List[str]:
"""Get the namespace of the langchain object."""
return ["langchain", "schema", "runnable"]
@property
def InputType(self) -> Type[Input]:
return self.default.InputType
@property
def OutputType(self) -> Type[Output]:
return self.default.OutputType
[docs] def get_output_schema(
self, config: Optional[RunnableConfig] = None
) -> Type[BaseModel]:
runnable, config = self._prepare(config)
return runnable.get_output_schema(config)
[docs] def get_graph(self, config: Optional[RunnableConfig] = None) -> Graph:
runnable, config = self._prepare(config)
return runnable.get_graph(config)
@abstractmethod
def _prepare(
self, config: Optional[RunnableConfig] = None
) -> Tuple[Runnable[Input, Output], RunnableConfig]:
...
[docs] def invoke(
self, input: Input, config: Optional[RunnableConfig] = None, **kwargs: Any
) -> Output:
runnable, config = self._prepare(config)
return runnable.invoke(input, config, **kwargs)
[docs] async def ainvoke(
self, input: Input, config: Optional[RunnableConfig] = None, **kwargs: Any
) -> Output:
runnable, config = self._prepare(config)
return await runnable.ainvoke(input, config, **kwargs)
[docs] def batch(
self,
inputs: List[Input],
config: Optional[Union[RunnableConfig, List[RunnableConfig]]] = None,
*,
return_exceptions: bool = False,
**kwargs: Optional[Any],
) -> List[Output]:
configs = get_config_list(config, len(inputs))
prepared = [self._prepare(c) for c in configs]
if all(p is self.default for p, _ in prepared):
return self.default.batch(
inputs,
[c for _, c in prepared],
return_exceptions=return_exceptions,
**kwargs,
)
if not inputs:
return []
def invoke(
prepared: Tuple[Runnable[Input, Output], RunnableConfig],
input: Input,
) -> Union[Output, Exception]:
bound, config = prepared
if return_exceptions:
try:
return bound.invoke(input, config, **kwargs)
except Exception as e:
return e
else:
return bound.invoke(input, config, **kwargs)
# If there's only one input, don't bother with the executor
if len(inputs) == 1:
return cast(List[Output], [invoke(prepared[0], inputs[0])])
with get_executor_for_config(configs[0]) as executor:
return cast(List[Output], list(executor.map(invoke, prepared, inputs)))
[docs] async def abatch(
self,
inputs: List[Input],
config: Optional[Union[RunnableConfig, List[RunnableConfig]]] = None,
*,
return_exceptions: bool = False,
**kwargs: Optional[Any],
) -> List[Output]:
configs = get_config_list(config, len(inputs))
prepared = [self._prepare(c) for c in configs]
if all(p is self.default for p, _ in prepared):
return await self.default.abatch(
inputs,
[c for _, c in prepared],
return_exceptions=return_exceptions,
**kwargs,
)
if not inputs:
return []
async def ainvoke(
prepared: Tuple[Runnable[Input, Output], RunnableConfig],
input: Input,
) -> Union[Output, Exception]:
bound, config = prepared
if return_exceptions:
try:
return await bound.ainvoke(input, config, **kwargs)
except Exception as e:
return e
else:
return await bound.ainvoke(input, config, **kwargs)
coros = map(ainvoke, prepared, inputs)
return await gather_with_concurrency(configs[0].get("max_concurrency"), *coros)
[docs] def stream(
self,
input: Input,
config: Optional[RunnableConfig] = None,
**kwargs: Optional[Any],
) -> Iterator[Output]:
runnable, config = self._prepare(config)
return runnable.stream(input, config, **kwargs)
[docs] async def astream(
self,
input: Input,
config: Optional[RunnableConfig] = None,
**kwargs: Optional[Any],
) -> AsyncIterator[Output]:
runnable, config = self._prepare(config)
async for chunk in runnable.astream(input, config, **kwargs):
yield chunk
[docs]class RunnableConfigurableFields(DynamicRunnable[Input, Output]):
"""A Runnable that can be dynamically configured."""
fields: Dict[str, AnyConfigurableField]
[docs] @classmethod
def get_lc_namespace(cls) -> List[str]:
"""Get the namespace of the langchain object."""
return ["langchain", "schema", "runnable"]
@property
def config_specs(self) -> List[ConfigurableFieldSpec]:
return get_unique_config_specs(
[
ConfigurableFieldSpec(
id=spec.id,
name=spec.name,
description=spec.description
or self.default.__fields__[field_name].field_info.description,
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(
spec, self.default.__fields__[field_name].field_info.description
)
for field_name, spec in self.fields.items()
]
+ list(self.default.config_specs)
)
[docs] def configurable_fields(
self, **kwargs: AnyConfigurableField
) -> RunnableSerializable[Input, Output]:
return self.default.configurable_fields(**{**self.fields, **kwargs})
def _prepare(
self, config: Optional[RunnableConfig] = None
) -> Tuple[Runnable[Input, Output], RunnableConfig]:
config = ensure_config(config)
specs_by_id = {spec.id: (key, spec) for key, spec in self.fields.items()}
configurable_fields = {
specs_by_id[k][0]: v
for k, v in config.get("configurable", {}).items()
if k in specs_by_id and isinstance(specs_by_id[k][1], ConfigurableField)
}
configurable_single_options = {
k: v.options[(config.get("configurable", {}).get(v.id) or v.default)]
for k, v in self.fields.items()
if isinstance(v, ConfigurableFieldSingleOption)
}
configurable_multi_options = {
k: [
v.options[o]
for o in config.get("configurable", {}).get(v.id, v.default)
]
for k, v in self.fields.items()
if isinstance(v, ConfigurableFieldMultiOption)
}
configurable = {
**configurable_fields,
**configurable_single_options,
**configurable_multi_options,
}
if configurable:
return (
self.default.__class__(**{**self.default.__dict__, **configurable}),
config,
)
else:
return (self.default, config)
# Before Python 3.11 native StrEnum is not available
[docs]class StrEnum(str, enum.Enum):
"""A string enum."""
pass
_enums_for_spec: WeakValueDictionary[
Union[
ConfigurableFieldSingleOption, ConfigurableFieldMultiOption, ConfigurableField
],
Type[StrEnum],
] = WeakValueDictionary()
_enums_for_spec_lock = threading.Lock()
[docs]class RunnableConfigurableAlternatives(DynamicRunnable[Input, Output]):
"""A Runnable that can be dynamically configured."""
which: ConfigurableField
alternatives: Dict[
str,
Union[Runnable[Input, Output], Callable[[], Runnable[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"."""
[docs] @classmethod
def get_lc_namespace(cls) -> List[str]:
"""Get the namespace of the langchain object."""
return ["langchain", "schema", "runnable"]
@property
def config_specs(self) -> List[ConfigurableFieldSpec]:
with _enums_for_spec_lock:
if which_enum := _enums_for_spec.get(self.which):
pass
else:
which_enum = StrEnum( # type: ignore[call-overload]
self.which.name or self.which.id,
(
(v, v)
for v in list(self.alternatives.keys()) + [self.default_key]
),
)
_enums_for_spec[self.which] = cast(Type[StrEnum], which_enum)
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
]
)
[docs] def configurable_fields(
self, **kwargs: AnyConfigurableField
) -> RunnableSerializable[Input, Output]:
return self.__class__(
which=self.which,
default=self.default.configurable_fields(**kwargs),
alternatives=self.alternatives,
)
def _prepare(
self, config: Optional[RunnableConfig] = None
) -> Tuple[Runnable[Input, Output], RunnableConfig]:
config = ensure_config(config)
which = config.get("configurable", {}).get(self.which.id, self.default_key)
# remap configurable keys for the chosen alternative
if self.prefix_keys:
config = cast(
RunnableConfig,
{
**config,
"configurable": {
_strremoveprefix(k, f"{self.which.id}=={which}/"): v
for k, v in config.get("configurable", {}).items()
},
},
)
# return the chosen alternative
if which == self.default_key:
return (self.default, config)
elif which in self.alternatives:
alt = self.alternatives[which]
if isinstance(alt, Runnable):
return (alt, config)
else:
return (alt(), config)
else:
raise ValueError(f"Unknown alternative: {which}")
def _strremoveprefix(s: str, prefix: str) -> str:
"""str.removeprefix() is only available in Python 3.9+."""
return s.replace(prefix, "", 1) if s.startswith(prefix) else s
[docs]def prefix_config_spec(
spec: ConfigurableFieldSpec, prefix: str
) -> ConfigurableFieldSpec:
"""Prefix the id of a ConfigurableFieldSpec.
This is useful when a RunnableConfigurableAlternatives is used as a
ConfigurableField of another RunnableConfigurableAlternatives.
Args:
spec: The ConfigurableFieldSpec to prefix.
prefix: The prefix to add.
Returns:
"""
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
)
[docs]def make_options_spec(
spec: Union[ConfigurableFieldSingleOption, ConfigurableFieldMultiOption],
description: Optional[str],
) -> ConfigurableFieldSpec:
"""Make a ConfigurableFieldSpec for a ConfigurableFieldSingleOption or
ConfigurableFieldMultiOption."""
with _enums_for_spec_lock:
if enum := _enums_for_spec.get(spec):
pass
else:
enum = StrEnum( # type: ignore[call-overload]
spec.name or spec.id,
((v, v) for v in list(spec.options.keys())),
)
_enums_for_spec[spec] = cast(Type[StrEnum], enum)
if isinstance(spec, ConfigurableFieldSingleOption):
return ConfigurableFieldSpec(
id=spec.id,
name=spec.name,
description=spec.description or description,
annotation=enum,
default=spec.default,
is_shared=spec.is_shared,
)
else:
return ConfigurableFieldSpec(
id=spec.id,
name=spec.name,
description=spec.description or description,
annotation=Sequence[enum], # type: ignore[valid-type]
default=spec.default,
is_shared=spec.is_shared,
)