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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
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# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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"""
TaskFlow decorator for LLM-driven branching.
The user writes a function that **returns the prompt string**. The decorator
discovers downstream tasks from the DAG topology and asks the LLM to choose
which branch(es) to execute using pydantic-ai structured output.
"""
from __future__ import annotations
from collections.abc import Callable, Collection, Mapping, Sequence
from typing import TYPE_CHECKING, Any, ClassVar
from airflow.providers.common.ai.operators.llm_branch import LLMBranchOperator
from airflow.providers.common.ai.utils.validation import validate_prompt
from airflow.providers.common.compat.sdk import (
DecoratedOperator,
TaskDecorator,
context_merge,
task_decorator_factory,
)
from airflow.sdk.definitions._internal.types import SET_DURING_EXECUTION
from airflow.utils.operator_helpers import determine_kwargs
if TYPE_CHECKING:
from airflow.sdk import Context
class _LLMBranchDecoratedOperator(DecoratedOperator, LLMBranchOperator):
"""
Wraps a callable that returns a prompt for LLM-driven branching.
The user function is called at execution time to produce the prompt string.
All other parameters (``llm_conn_id``, ``system_prompt``, ``allow_multiple_branches``,
etc.) are passed through to
:class:`~airflow.providers.common.ai.operators.llm_branch.LLMBranchOperator`.
:param python_callable: A reference to a callable that returns the prompt string.
:param op_args: Positional arguments for the callable.
:param op_kwargs: Keyword arguments for the callable.
"""
template_fields: Sequence[str] = (
*DecoratedOperator.template_fields,
*LLMBranchOperator.template_fields,
)
template_fields_renderers: ClassVar[dict[str, str]] = {
**DecoratedOperator.template_fields_renderers,
}
custom_operator_name: str = "@task.llm_branch"
def __init__(
self,
*,
python_callable: Callable,
op_args: Collection[Any] | None = None,
op_kwargs: Mapping[str, Any] | None = None,
**kwargs,
) -> None:
super().__init__(
python_callable=python_callable,
op_args=op_args,
op_kwargs=op_kwargs,
prompt=SET_DURING_EXECUTION,
**kwargs,
)
def execute(self, context: Context) -> Any:
context_merge(context, self.op_kwargs)
kwargs = determine_kwargs(self.python_callable, self.op_args, context)
self.prompt = self.python_callable(*self.op_args, **kwargs)
validate_prompt(self.prompt, decorator_name="@task.llm_branch")
self.render_template_fields(context)
return LLMBranchOperator.execute(self, context)
[docs]
def llm_branch_task(
python_callable: Callable | None = None,
**kwargs,
) -> TaskDecorator:
"""
Wrap a function that returns a prompt into an LLM-driven branching task.
The function body constructs the prompt. The decorator discovers downstream
tasks from the DAG topology and asks the LLM to choose which branch(es)
to execute.
Usage::
@task.llm_branch(
llm_conn_id="openai_default",
system_prompt="Route support tickets to the right team.",
)
def route_ticket(message: str):
return f"Route this ticket: {message}"
With multiple branches::
@task.llm_branch(
llm_conn_id="openai_default",
system_prompt="Select all applicable categories.",
allow_multiple_branches=True,
)
def classify(text: str):
return f"Classify this text: {text}"
:param python_callable: Function to decorate.
"""
return task_decorator_factory(
python_callable=python_callable,
decorated_operator_class=_LLMBranchDecoratedOperator,
**kwargs,
)