"""
The ``mlflow.langchain`` module provides an API for logging and loading LangChain models.
This module exports multivariate LangChain models in the langchain flavor and univariate
LangChain models in the pyfunc flavor:
LangChain (native) format
This is the main flavor that can be accessed with LangChain APIs.
:py:mod:`mlflow.pyfunc`
Produced for use by generic pyfunc-based deployment tools and for batch inference.
.. _LangChain:
https://python.langchain.com/en/latest/index.html
"""
import logging
import os
import tempfile
import warnings
from typing import Any, Iterator, Optional, Union
import cloudpickle
import pandas as pd
import yaml
from packaging.version import Version
import mlflow
from mlflow import pyfunc
from mlflow.entities.model_registry.prompt import Prompt
from mlflow.exceptions import MlflowException
from mlflow.langchain.constants import FLAVOR_NAME
from mlflow.langchain.databricks_dependencies import _detect_databricks_dependencies
from mlflow.langchain.runnables import _load_runnables, _save_runnables
from mlflow.langchain.utils.logging import (
_BASE_LOAD_KEY,
_MODEL_LOAD_KEY,
_RUNNABLE_LOAD_KEY,
_load_base_lcs,
_save_base_lcs,
_validate_and_prepare_lc_model_or_path,
lc_runnables_types,
patch_langchain_type_to_cls_dict,
register_pydantic_v1_serializer_cm,
)
from mlflow.models import Model, ModelInputExample, ModelSignature
from mlflow.models.dependencies_schemas import (
_clear_dependencies_schemas,
_get_dependencies_schema_from_model,
_get_dependencies_schemas,
)
from mlflow.models.model import (
MLMODEL_FILE_NAME,
MODEL_CODE_PATH,
MODEL_CONFIG,
_update_active_model_id_based_on_mlflow_model,
)
from mlflow.models.resources import DatabricksFunction, Resource, _ResourceBuilder
from mlflow.models.signature import _infer_signature_from_input_example
from mlflow.models.utils import (
_convert_llm_input_data,
_load_model_code_path,
_save_example,
)
from mlflow.pyfunc import FLAVOR_NAME as PYFUNC_FLAVOR_NAME
from mlflow.pyfunc.context import Context
from mlflow.tracing.provider import trace_disabled
from mlflow.tracking._model_registry import DEFAULT_AWAIT_MAX_SLEEP_SECONDS
from mlflow.tracking.artifact_utils import _download_artifact_from_uri
from mlflow.types.schema import ColSpec, DataType, Schema
from mlflow.utils.databricks_utils import (
_get_databricks_serverless_env_vars,
is_in_databricks_model_serving_environment,
is_in_databricks_serverless_runtime,
is_mlflow_tracing_enabled_in_model_serving,
)
from mlflow.utils.docstring_utils import (
LOG_MODEL_PARAM_DOCS,
docstring_version_compatibility_warning,
format_docstring,
)
from mlflow.utils.environment import (
_CONDA_ENV_FILE_NAME,
_CONSTRAINTS_FILE_NAME,
_PYTHON_ENV_FILE_NAME,
_REQUIREMENTS_FILE_NAME,
_mlflow_conda_env,
_process_conda_env,
_process_pip_requirements,
_PythonEnv,
_validate_env_arguments,
)
from mlflow.utils.file_utils import get_total_file_size, write_to
from mlflow.utils.model_utils import (
_add_code_from_conf_to_system_path,
_get_flavor_configuration,
_validate_and_copy_code_paths,
_validate_and_copy_file_to_directory,
_validate_and_get_model_config_from_file,
_validate_and_prepare_target_save_path,
)
from mlflow.utils.requirements_utils import _get_pinned_requirement
logger = logging.getLogger(mlflow.__name__)
_MODEL_TYPE_KEY = "model_type"
def get_default_pip_requirements():
"""
Returns:
A list of default pip requirements for MLflow Models produced by this flavor.
Calls to :func:`save_model()` and :func:`log_model()` produce a pip environment
that, at a minimum, contains these requirements.
"""
# pin pydantic and cloudpickle version as they are used in langchain
# model saving and loading
return list(map(_get_pinned_requirement, ["langchain", "pydantic", "cloudpickle"]))
def get_default_conda_env():
"""
Returns:
The default Conda environment for MLflow Models produced by calls to
:func:`save_model()` and :func:`log_model()`.
"""
return _mlflow_conda_env(additional_pip_deps=get_default_pip_requirements())
[docs]@format_docstring(LOG_MODEL_PARAM_DOCS.format(package_name=FLAVOR_NAME))
@docstring_version_compatibility_warning(FLAVOR_NAME)
@trace_disabled # Suppress traces for internal predict calls while saving model
def save_model(
lc_model,
path,
conda_env=None,
code_paths=None,
mlflow_model=None,
signature: ModelSignature = None,
input_example: ModelInputExample = None,
pip_requirements=None,
extra_pip_requirements=None,
metadata=None,
loader_fn=None,
persist_dir=None,
model_config=None,
streamable: Optional[bool] = None,
):
"""
Save a LangChain model to a path on the local file system.
Args:
lc_model: A LangChain model, which could be a
`Chain <https://python.langchain.com/docs/modules/chains/>`_,
`Agent <https://python.langchain.com/docs/modules/agents/>`_,
`retriever <https://python.langchain.com/docs/modules/data_connection/retrievers/>`_,
or `RunnableSequence <https://python.langchain.com/docs/modules/chains/foundational/sequential_chains#using-lcel>`_,
or a path containing the `LangChain model code <https://github.com/mlflow/mlflow/blob/master/examples/langchain/chain_as_code_driver.py>`
for the above types. When using model as path, make sure to set the model
by using :func:`mlflow.models.set_model()`.
.. Note:: Experimental: Using model as path may change or be removed in a future
release without warning.
path: Local path where the serialized model (as YAML) is to be saved.
conda_env: {{ conda_env }}
code_paths: {{ code_paths }}
mlflow_model: :py:mod:`mlflow.models.Model` this flavor is being added to.
signature: :py:class:`ModelSignature <mlflow.models.ModelSignature>`
describes model input and output :py:class:`Schema <mlflow.types.Schema>`.
If not specified, the model signature would be set according to
`lc_model.input_keys` and `lc_model.output_keys` as columns names, and
`DataType.string` as the column type.
Alternatively, you can explicitly specify the model signature.
The model signature can be :py:func:`inferred <mlflow.models.infer_signature>`
from datasets with valid model input (e.g. the training dataset with target
column omitted) and valid model output (e.g. model predictions generated on
the training dataset), for example:
.. code-block:: python
from mlflow.models import infer_signature
chain = LLMChain(llm=llm, prompt=prompt)
prediction = chain.run(input_str)
input_columns = [
{"type": "string", "name": input_key} for input_key in chain.input_keys
]
signature = infer_signature(input_columns, predictions)
input_example: {{ input_example }}
pip_requirements: {{ pip_requirements }}
extra_pip_requirements: {{ extra_pip_requirements }}
metadata: {{ metadata }}
loader_fn: A function that's required for models containing objects that aren't natively
serialized by LangChain.
This function takes a string `persist_dir` as an argument and returns the
specific object that the model needs. Depending on the model,
this could be a retriever, vectorstore, requests_wrapper, embeddings, or
database. For RetrievalQA Chain and retriever models, the object is a
(`retriever <https://python.langchain.com/docs/modules/data_connection/retrievers/>`_).
For APIChain models, it's a
(`requests_wrapper <https://python.langchain.com/docs/modules/agents/tools/integrations/requests>`_).
For HypotheticalDocumentEmbedder models, it's an
(`embeddings <https://python.langchain.com/docs/modules/data_connection/text_embedding/>`_).
For SQLDatabaseChain models, it's a
(`database <https://python.langchain.com/docs/modules/agents/toolkits/sql_database>`_).
persist_dir: The directory where the object is stored. The `loader_fn`
takes this string as the argument to load the object.
This is optional for models containing objects that aren't natively
serialized by LangChain. MLflow logs the content in this directory as
artifacts in the subdirectory named `persist_dir_data`.
Here is the code snippet for logging a RetrievalQA chain with `loader_fn`
and `persist_dir`:
.. Note:: In langchain_community >= 0.0.27, loading pickled data requires providing the
``allow_dangerous_deserialization`` argument.
.. code-block:: python
qa = RetrievalQA.from_llm(llm=OpenAI(), retriever=db.as_retriever())
def load_retriever(persist_directory):
embeddings = OpenAIEmbeddings()
vectorstore = FAISS.load_local(
persist_directory,
embeddings,
# you may need to add the line below
# for langchain_community >= 0.0.27
allow_dangerous_deserialization=True,
)
return vectorstore.as_retriever()
with mlflow.start_run() as run:
logged_model = mlflow.langchain.log_model(
qa,
name="retrieval_qa",
loader_fn=load_retriever,
persist_dir=persist_dir,
)
See a complete example in examples/langchain/retrieval_qa_chain.py.
model_config: The model configuration to apply to the model if saving model from code. This
configuration is available during model loading.
.. Note:: Experimental: This parameter may change or be removed in a future
release without warning.
streamable: A boolean value indicating if the model supports streaming prediction. If
True, the model must implement `stream` method. If None, streamable is
set to True if the model implements `stream` method. Default to `None`.
"""
with tempfile.TemporaryDirectory() as temp_dir:
import langchain
from langchain.schema import BaseRetriever
lc_model_or_path = _validate_and_prepare_lc_model_or_path(lc_model, loader_fn, temp_dir)
_validate_env_arguments(conda_env, pip_requirements, extra_pip_requirements)
path = os.path.abspath(path)
_validate_and_prepare_target_save_path(path)
if isinstance(model_config, str):
model_config = _validate_and_get_model_config_from_file(model_config)
model_code_path = None
if isinstance(lc_model_or_path, str):
# The LangChain model is defined as Python code located in the file at the path
# specified by `lc_model`. Verify that the path exists and, if so, copy it to the
# model directory along with any other specified code modules
model_code_path = lc_model_or_path
lc_model = _load_model_code_path(model_code_path, model_config)
_validate_and_copy_file_to_directory(model_code_path, path, "code")
else:
lc_model = lc_model_or_path
code_dir_subpath = _validate_and_copy_code_paths(code_paths, path)
if mlflow_model is None:
mlflow_model = Model()
saved_example = _save_example(mlflow_model, input_example, path)
if signature is None:
if saved_example is not None:
wrapped_model = _LangChainModelWrapper(lc_model)
signature = _infer_signature_from_input_example(saved_example, wrapped_model)
else:
if hasattr(lc_model, "input_keys"):
input_columns = [
ColSpec(type=DataType.string, name=input_key)
for input_key in lc_model.input_keys
]
input_schema = Schema(input_columns)
else:
input_schema = None
if (
hasattr(lc_model, "output_keys")
and len(lc_model.output_keys) == 1
and not isinstance(lc_model, BaseRetriever)
):
output_columns = [
ColSpec(type=DataType.string, name=output_key)
for output_key in lc_model.output_keys
]
output_schema = Schema(output_columns)
else:
# TODO: empty output schema if multiple output_keys or is a retriever. fix later!
# https://databricks.atlassian.net/browse/ML-34706
output_schema = None
signature = (
ModelSignature(input_schema, output_schema)
if input_schema or output_schema
else None
)
if signature is not None:
mlflow_model.signature = signature
if metadata is not None:
mlflow_model.metadata = metadata
with _get_dependencies_schemas() as dependencies_schemas:
schema = dependencies_schemas.to_dict()
if schema is not None:
if mlflow_model.metadata is None:
mlflow_model.metadata = {}
mlflow_model.metadata.update(schema)
if streamable is None:
streamable = hasattr(lc_model, "stream")
model_data_kwargs = {}
flavor_conf = {}
if not isinstance(model_code_path, str):
model_data_kwargs = _save_model(lc_model, path, loader_fn, persist_dir)
flavor_conf = {
_MODEL_TYPE_KEY: lc_model.__class__.__name__,
**model_data_kwargs,
}
pyfunc.add_to_model(
mlflow_model,
loader_module="mlflow.langchain",
conda_env=_CONDA_ENV_FILE_NAME,
python_env=_PYTHON_ENV_FILE_NAME,
code=code_dir_subpath,
predict_stream_fn="predict_stream",
streamable=streamable,
model_code_path=model_code_path,
model_config=model_config,
**model_data_kwargs,
)
needs_databricks_auth = False
if Version(langchain.__version__) >= Version("0.0.311") and mlflow_model.resources is None:
if databricks_resources := _detect_databricks_dependencies(lc_model):
logger.info(
"Attempting to auto-detect Databricks resource dependencies for the "
"current langchain model. Dependency auto-detection is "
"best-effort and may not capture all dependencies of your langchain "
"model, resulting in authorization errors when serving or querying "
"your model. We recommend that you explicitly pass `resources` "
"to mlflow.langchain.log_model() to ensure authorization to "
"dependent resources succeeds when the model is deployed."
)
serialized_databricks_resources = _ResourceBuilder.from_resources(databricks_resources)
mlflow_model.resources = serialized_databricks_resources
needs_databricks_auth = any(
isinstance(r, DatabricksFunction) for r in databricks_resources
)
mlflow_model.add_flavor(
FLAVOR_NAME,
langchain_version=langchain.__version__,
code=code_dir_subpath,
streamable=streamable,
**flavor_conf,
)
if size := get_total_file_size(path):
mlflow_model.model_size_bytes = size
mlflow_model.save(os.path.join(path, MLMODEL_FILE_NAME))
if conda_env is None:
if pip_requirements is None:
default_reqs = get_default_pip_requirements()
extra_env_vars = (
_get_databricks_serverless_env_vars()
if needs_databricks_auth and is_in_databricks_serverless_runtime()
else None
)
inferred_reqs = mlflow.models.infer_pip_requirements(
str(path), FLAVOR_NAME, fallback=default_reqs, extra_env_vars=extra_env_vars
)
default_reqs = sorted(set(inferred_reqs).union(default_reqs))
else:
default_reqs = None
conda_env, pip_requirements, pip_constraints = _process_pip_requirements(
default_reqs, pip_requirements, extra_pip_requirements
)
else:
conda_env, pip_requirements, pip_constraints = _process_conda_env(conda_env)
with open(os.path.join(path, _CONDA_ENV_FILE_NAME), "w") as f:
yaml.safe_dump(conda_env, stream=f, default_flow_style=False)
if pip_constraints:
write_to(os.path.join(path, _CONSTRAINTS_FILE_NAME), "\n".join(pip_constraints))
write_to(os.path.join(path, _REQUIREMENTS_FILE_NAME), "\n".join(pip_requirements))
_PythonEnv.current().to_yaml(os.path.join(path, _PYTHON_ENV_FILE_NAME))
[docs]@format_docstring(LOG_MODEL_PARAM_DOCS.format(package_name=FLAVOR_NAME))
@docstring_version_compatibility_warning(FLAVOR_NAME)
@trace_disabled # Suppress traces for internal predict calls while logging model
def log_model(
lc_model,
artifact_path: Optional[str] = None,
conda_env=None,
code_paths=None,
registered_model_name=None,
signature: ModelSignature = None,
input_example: ModelInputExample = None,
await_registration_for=DEFAULT_AWAIT_MAX_SLEEP_SECONDS,
pip_requirements=None,
extra_pip_requirements=None,
metadata=None,
loader_fn=None,
persist_dir=None,
run_id=None,
model_config=None,
streamable=None,
resources: Optional[Union[list[Resource], str]] = None,
prompts: Optional[list[Union[str, Prompt]]] = None,
name: Optional[str] = None,
params: Optional[dict[str, Any]] = None,
tags: Optional[dict[str, Any]] = None,
model_type: Optional[str] = None,
step: int = 0,
model_id: Optional[str] = None,
):
"""
Log a LangChain model as an MLflow artifact for the current run.
Args:
lc_model: A LangChain model, which could be a
`Chain <https://python.langchain.com/docs/modules/chains/>`_,
`Agent <https://python.langchain.com/docs/modules/agents/>`_, or
`retriever <https://python.langchain.com/docs/modules/data_connection/retrievers/>`_
or a path containing the `LangChain model code <https://github.com/mlflow/mlflow/blob/master/examples/langchain/chain_as_code_driver.py>`
for the above types. When using model as path, make sure to set the model
by using :func:`mlflow.models.set_model()`.
.. Note:: Experimental: Using model as path may change or be removed in a future
release without warning.
artifact_path: Deprecated. Use `name` instead.
conda_env: {{ conda_env }}
code_paths: {{ code_paths }}
registered_model_name: If given, create a model
version under ``registered_model_name``, also creating a
registered model if one with the given name does not exist.
signature: :py:class:`ModelSignature <mlflow.models.ModelSignature>`
describes model input and output
:py:class:`Schema <mlflow.types.Schema>`.
If not specified, the model signature would be set according to
`lc_model.input_keys` and `lc_model.output_keys` as columns names, and
`DataType.string` as the column type.
Alternatively, you can explicitly specify the model signature.
The model signature can be :py:func:`inferred
<mlflow.models.infer_signature>` from datasets with valid model input
(e.g. the training dataset with target column omitted) and valid model
output (e.g. model predictions generated on the training dataset),
for example:
.. code-block:: python
from mlflow.models import infer_signature
chain = LLMChain(llm=llm, prompt=prompt)
prediction = chain.run(input_str)
input_columns = [
{"type": "string", "name": input_key} for input_key in chain.input_keys
]
signature = infer_signature(input_columns, predictions)
input_example: {{ input_example }}
await_registration_for: Number of seconds to wait for the model version
to finish being created and is in ``READY`` status.
By default, the function waits for five minutes.
Specify 0 or None to skip waiting.
pip_requirements: {{ pip_requirements }}
extra_pip_requirements: {{ extra_pip_requirements }}
metadata: {{ metadata }}
loader_fn: A function that's required for models containing objects that aren't natively
serialized by LangChain.
This function takes a string `persist_dir` as an argument and returns the
specific object that the model needs. Depending on the model,
this could be a retriever, vectorstore, requests_wrapper, embeddings, or
database. For RetrievalQA Chain and retriever models, the object is a
(`retriever <https://python.langchain.com/docs/modules/data_connection/retrievers/>`_).
For APIChain models, it's a
(`requests_wrapper <https://python.langchain.com/docs/modules/agents/tools/integrations/requests>`_).
For HypotheticalDocumentEmbedder models, it's an
(`embeddings <https://python.langchain.com/docs/modules/data_connection/text_embedding/>`_).
For SQLDatabaseChain models, it's a
(`database <https://python.langchain.com/docs/modules/agents/toolkits/sql_database>`_).
persist_dir: The directory where the object is stored. The `loader_fn`
takes this string as the argument to load the object.
This is optional for models containing objects that aren't natively
serialized by LangChain. MLflow logs the content in this directory as
artifacts in the subdirectory named `persist_dir_data`.
Here is the code snippet for logging a RetrievalQA chain with `loader_fn`
and `persist_dir`:
.. Note:: In langchain_community >= 0.0.27, loading pickled data requires providing the
``allow_dangerous_deserialization`` argument.
.. code-block:: python
qa = RetrievalQA.from_llm(llm=OpenAI(), retriever=db.as_retriever())
def load_retriever(persist_directory):
embeddings = OpenAIEmbeddings()
vectorstore = FAISS.load_local(
persist_directory,
embeddings,
# you may need to add the line below
# for langchain_community >= 0.0.27
allow_dangerous_deserialization=True,
)
return vectorstore.as_retriever()
with mlflow.start_run() as run:
logged_model = mlflow.langchain.log_model(
qa,
name="retrieval_qa",
loader_fn=load_retriever,
persist_dir=persist_dir,
)
See a complete example in examples/langchain/retrieval_qa_chain.py.
run_id: run_id to associate with this model version. If specified, we resume the
run and log the model to that run. Otherwise, a new run is created.
Default to None.
model_config: The model configuration to apply to the model if saving model from code. This
configuration is available during model loading.
.. Note:: Experimental: This parameter may change or be removed in a future
release without warning.
streamable: A boolean value indicating if the model supports streaming prediction. If
True, the model must implement `stream` method. If None, If None, streamable is
set to True if the model implements `stream` method. Default to `None`.
resources: A list of model resources or a resources.yaml file containing a list of
resources required to serve the model. If logging a LangChain model with dependencies
(e.g. on LLM model serving endpoints), we encourage explicitly passing dependencies
via this parameter. Otherwise, ``log_model`` will attempt to infer dependencies,
but dependency auto-inference is best-effort and may miss some dependencies.
prompts: {{ prompts }}
name: {{ name }}
params: {{ params }}
tags: {{ tags }}
model_type: {{ model_type }}
step: {{ step }}
model_id: {{ model_id }}
Returns:
A :py:class:`ModelInfo <mlflow.models.model.ModelInfo>` instance that contains the
metadata of the logged model.
"""
return Model.log(
artifact_path=artifact_path,
name=name,
flavor=mlflow.langchain,
registered_model_name=registered_model_name,
lc_model=lc_model,
conda_env=conda_env,
code_paths=code_paths,
signature=signature,
input_example=input_example,
await_registration_for=await_registration_for,
pip_requirements=pip_requirements,
extra_pip_requirements=extra_pip_requirements,
metadata=metadata,
loader_fn=loader_fn,
persist_dir=persist_dir,
run_id=run_id,
model_config=model_config,
streamable=streamable,
resources=resources,
prompts=prompts,
params=params,
tags=tags,
model_type=model_type,
step=step,
model_id=model_id,
)
# patch_langchain_type_to_cls_dict here as we attempt to load model
# if it's saved by `dict` method
@patch_langchain_type_to_cls_dict
def _save_model(model, path, loader_fn, persist_dir):
if Version(cloudpickle.__version__) < Version("2.1.0"):
warnings.warn(
"If you are constructing a custom LangChain model, "
"please upgrade cloudpickle to version 2.1.0 or later "
"using `pip install cloudpickle>=2.1.0` "
"to ensure the model can be loaded correctly."
)
with register_pydantic_v1_serializer_cm():
if isinstance(model, lc_runnables_types()):
return _save_runnables(model, path, loader_fn=loader_fn, persist_dir=persist_dir)
else:
return _save_base_lcs(model, path, loader_fn, persist_dir)
@patch_langchain_type_to_cls_dict
def _load_model(local_model_path, flavor_conf):
# model_type is not accurate as the class can be subclass
# of supported types, we define _MODEL_LOAD_KEY to ensure
# which load function to use
model_load_fn = flavor_conf.get(_MODEL_LOAD_KEY)
with register_pydantic_v1_serializer_cm():
if model_load_fn == _RUNNABLE_LOAD_KEY:
model = _load_runnables(local_model_path, flavor_conf)
elif model_load_fn == _BASE_LOAD_KEY:
model = _load_base_lcs(local_model_path, flavor_conf)
else:
raise mlflow.MlflowException(
"Failed to load LangChain model. Unknown model type: "
f"{flavor_conf.get(_MODEL_TYPE_KEY)}"
)
return model
class _LangChainModelWrapper:
def __init__(self, lc_model, model_path=None):
self.lc_model = lc_model
self.model_path = model_path
def get_raw_model(self):
"""
Returns the underlying model.
"""
return self.lc_model
def predict(
self,
data: Union[pd.DataFrame, list[Union[str, dict[str, Any]]], Any],
params: Optional[dict[str, Any]] = None,
) -> list[Union[str, dict[str, Any]]]:
"""
Args:
data: Model input data.
params: Additional parameters to pass to the model for inference.
Returns:
Model predictions.
"""
# TODO: We don't automatically turn tracing on in OSS model serving, because we haven't
# implemented storage option for traces in OSS model serving (counterpart to the
# Inference Table in Databricks model serving).
if (
is_in_databricks_model_serving_environment()
# TODO: This env var was once used for controlling whether or not to inject the
# tracer in Databricks model serving. However, now we have the new env var
# `ENABLE_MLFLOW_TRACING` to control that. We don't remove this condition
# right now in the interest of caution, but we should remove this condition
# after making sure that the functionality is stable.
and os.environ.get("MLFLOW_ENABLE_TRACE_IN_SERVING", "false").lower() == "true"
# if this is False, tracing is disabled and we shouldn't inject the tracer
and is_mlflow_tracing_enabled_in_model_serving()
):
from mlflow.langchain.langchain_tracer import MlflowLangchainTracer
callbacks = [MlflowLangchainTracer()]
else:
callbacks = None
return self._predict_with_callbacks(data, params, callback_handlers=callbacks)
def _update_dependencies_schemas_in_prediction_context(
self, callback_handlers
) -> Optional[Context]:
from mlflow.langchain.langchain_tracer import MlflowLangchainTracer
if (
callback_handlers
and (
tracer := next(
(c for c in callback_handlers if isinstance(c, MlflowLangchainTracer)), None
)
)
and self.model_path
):
model = Model.load(self.model_path)
context = tracer._prediction_context
if context and (schema := _get_dependencies_schema_from_model(model)):
context.update(**schema)
return context
def _predict_with_callbacks(
self,
data: Union[pd.DataFrame, list[Union[str, dict[str, Any]]], Any],
params: Optional[dict[str, Any]] = None,
callback_handlers=None,
convert_chat_responses=False,
) -> list[Union[str, dict[str, Any]]]:
"""
Args:
data: Model input data.
params: Additional parameters to pass to the model for inference.
callback_handlers: Callback handlers to pass to LangChain.
convert_chat_responses: If true, forcibly convert response to chat model
response format.
Returns:
Model predictions.
"""
from mlflow.langchain.api_request_parallel_processor import process_api_requests
context = self._update_dependencies_schemas_in_prediction_context(callback_handlers)
messages, return_first_element = self._prepare_predict_messages(data)
results = process_api_requests(
lc_model=self.lc_model,
requests=messages,
callback_handlers=callback_handlers,
convert_chat_responses=convert_chat_responses,
params=params or {},
context=context,
)
return results[0] if return_first_element else results
def _prepare_predict_messages(self, data):
"""
Return a tuple of (preprocessed_data, return_first_element)
`preprocessed_data` is always a list,
and `return_first_element` means if True, we should return the first element
of inference result, otherwise we should return the whole inference result.
"""
data = _convert_llm_input_data(data)
if not isinstance(data, list):
# if the input data is not a list (i.e. single input),
# we still need to convert it to a one-element list `[data]`
# because `process_api_requests` only accepts list as valid input.
# and in this case,
# we should return the first element of the inference result
# because we change input `data` to `[data]`
return [data], True
if isinstance(data, list):
return data, False
raise mlflow.MlflowException.invalid_parameter_value(
"Input must be a pandas DataFrame or a list "
f"for model {self.lc_model.__class__.__name__}"
)
def _prepare_predict_stream_messages(self, data):
data = _convert_llm_input_data(data)
if isinstance(data, list):
# `predict_stream` only accepts single input.
# but `enforce_schema` might convert single input into a list like `[single_input]`
# so extract the first element in the list.
if len(data) != 1:
raise MlflowException(
f"'predict_stream' requires single input, but it got input data {data}"
)
return data[0]
return data
def predict_stream(
self,
data: Any,
params: Optional[dict[str, Any]] = None,
) -> Iterator[Union[str, dict[str, Any]]]:
"""
Args:
data: Model input data, only single input is allowed.
params: Additional parameters to pass to the model for inference.
Returns:
An iterator of model prediction chunks.
"""
from mlflow.langchain.api_request_parallel_processor import (
process_stream_request,
)
data = self._prepare_predict_stream_messages(data)
return process_stream_request(
lc_model=self.lc_model,
request_json=data,
params=params or {},
)
def _predict_stream_with_callbacks(
self,
data: Any,
params: Optional[dict[str, Any]] = None,
callback_handlers=None,
convert_chat_responses=False,
) -> Iterator[Union[str, dict[str, Any]]]:
"""
Args:
data: Model input data, only single input is allowed.
params: Additional parameters to pass to the model for inference.
callback_handlers: Callback handlers to pass to LangChain.
convert_chat_responses: If true, forcibly convert response to chat model
response format.
Returns:
An iterator of model prediction chunks.
"""
from mlflow.langchain.api_request_parallel_processor import (
process_stream_request,
)
self._update_dependencies_schemas_in_prediction_context(callback_handlers)
data = self._prepare_predict_stream_messages(data)
return process_stream_request(
lc_model=self.lc_model,
request_json=data,
callback_handlers=callback_handlers,
convert_chat_responses=convert_chat_responses,
params=params or {},
)
def _load_pyfunc(path: str, model_config: Optional[dict[str, Any]] = None):
"""Load PyFunc implementation for LangChain. Called by ``pyfunc.load_model``.
Args:
path: Local filesystem path to the MLflow Model with the ``langchain`` flavor.
"""
return _LangChainModelWrapper(_load_model_from_local_fs(path, model_config), path)
def _load_model_from_local_fs(local_model_path, model_config_overrides=None):
mlflow_model = Model.load(local_model_path)
flavor_conf = _get_flavor_configuration(model_path=local_model_path, flavor_name=FLAVOR_NAME)
pyfunc_flavor_conf = _get_flavor_configuration(
model_path=local_model_path, flavor_name=PYFUNC_FLAVOR_NAME
)
# Add code from the langchain flavor to the system path
_add_code_from_conf_to_system_path(local_model_path, flavor_conf)
# The model_code_path and the model_config were previously saved langchain flavor but now we
# also save them inside the pyfunc flavor. For backwards compatibility of previous models,
# we need to check both places.
if MODEL_CODE_PATH in pyfunc_flavor_conf or MODEL_CODE_PATH in flavor_conf:
model_config = pyfunc_flavor_conf.get(MODEL_CONFIG, flavor_conf.get(MODEL_CONFIG, None))
if isinstance(model_config, str):
config_path = os.path.join(
local_model_path,
os.path.basename(model_config),
)
model_config = _validate_and_get_model_config_from_file(config_path)
flavor_code_path = pyfunc_flavor_conf.get(
MODEL_CODE_PATH, flavor_conf.get(MODEL_CODE_PATH, None)
)
model_code_path = os.path.join(
local_model_path,
os.path.basename(flavor_code_path),
)
try:
model = _load_model_code_path(
model_code_path, {**(model_config or {}), **(model_config_overrides or {})}
)
finally:
# We would like to clean up the dependencies schema which is set to global
# after loading the mode to avoid the schema being used in the next model loading
_clear_dependencies_schemas()
else:
model = _load_model(local_model_path, flavor_conf)
# set active model after model loading since experiment ID might be set
# in the model loading process
_update_active_model_id_based_on_mlflow_model(mlflow_model)
return model
[docs]@docstring_version_compatibility_warning(FLAVOR_NAME)
@trace_disabled # Suppress traces while loading model
def load_model(model_uri, dst_path=None):
"""
Load a LangChain model from a local file or a run.
Args:
model_uri: The location, in URI format, of the MLflow model. For example:
- ``/Users/me/path/to/local/model``
- ``relative/path/to/local/model``
- ``s3://my_bucket/path/to/model``
- ``runs:/<mlflow_run_id>/run-relative/path/to/model``
For more information about supported URI schemes, see
`Referencing Artifacts <https://www.mlflow.org/docs/latest/tracking.html#
artifact-locations>`_.
dst_path: The local filesystem path to which to download the model artifact.
This directory must already exist. If unspecified, a local output
path will be created.
Returns:
A LangChain model instance.
"""
model_uri = str(model_uri)
local_model_path = _download_artifact_from_uri(artifact_uri=model_uri, output_path=dst_path)
return _load_model_from_local_fs(local_model_path)