# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# 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
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations
from airflow.exceptions import AirflowOptionalProviderFeatureException
from airflow.providers.standard.version_compat import AIRFLOW_V_3_1_PLUS
if not AIRFLOW_V_3_1_PLUS:
raise AirflowOptionalProviderFeatureException("Human in the loop functionality needs Airflow 3.1+.")
import asyncio
from collections.abc import AsyncIterator
from datetime import datetime
from typing import TYPE_CHECKING, Any, Literal, TypedDict
from uuid import UUID
from asgiref.sync import sync_to_async
from airflow.sdk.execution_time.hitl import (
HITLUser,
get_hitl_detail_content_detail,
update_hitl_detail_response,
)
from airflow.sdk.timezone import utcnow
from airflow.triggers.base import BaseTrigger, TriggerEvent
[docs]
class HITLTriggerEventSuccessPayload(TypedDict, total=False):
"""Minimum required keys for a success Human-in-the-loop TriggerEvent."""
[docs]
chosen_options: list[str]
[docs]
responded_by_user: HITLUser | None
[docs]
class HITLTriggerEventFailurePayload(TypedDict):
"""Minimum required keys for a failed Human-in-the-loop TriggerEvent."""
[docs]
error_type: Literal["timeout", "unknown"]
[docs]
class HITLTrigger(BaseTrigger):
"""A trigger that checks whether Human-in-the-loop responses are received."""
def __init__(
self,
*,
ti_id: UUID,
options: list[str],
params: dict[str, Any],
defaults: list[str] | None = None,
multiple: bool = False,
timeout_datetime: datetime | None,
poke_interval: float = 5.0,
**kwargs,
):
super().__init__(**kwargs)
[docs]
self.poke_interval = poke_interval
[docs]
self.multiple = multiple
[docs]
self.defaults = defaults
[docs]
self.timeout_datetime = timeout_datetime
[docs]
def serialize(self) -> tuple[str, dict[str, Any]]:
"""Serialize HITLTrigger arguments and classpath."""
return (
"airflow.providers.standard.triggers.hitl.HITLTrigger",
{
"ti_id": self.ti_id,
"options": self.options,
"defaults": self.defaults,
"params": self.params,
"multiple": self.multiple,
"timeout_datetime": self.timeout_datetime,
"poke_interval": self.poke_interval,
},
)
[docs]
async def run(self) -> AsyncIterator[TriggerEvent]:
"""Loop until the Human-in-the-loop response received or timeout reached."""
while True:
if self.timeout_datetime and self.timeout_datetime < utcnow():
# Fetch latest HITL detail before fallback
resp = await sync_to_async(get_hitl_detail_content_detail)(ti_id=self.ti_id)
# Response already received, yield success and exit
if resp.response_received and resp.chosen_options:
if TYPE_CHECKING:
assert resp.responded_by_user is not None
assert resp.responded_at is not None
self.log.info(
"[HITL] responded_by=%s (id=%s) options=%s at %s (timeout fallback skipped)",
resp.responded_by_user.name,
resp.responded_by_user.id,
resp.chosen_options,
resp.responded_at,
)
yield TriggerEvent(
HITLTriggerEventSuccessPayload(
chosen_options=resp.chosen_options,
params_input=resp.params_input or {},
responded_at=resp.responded_at,
responded_by_user=HITLUser(
id=resp.responded_by_user.id,
name=resp.responded_by_user.name,
),
timedout=False,
)
)
return
if self.defaults is None:
yield TriggerEvent(
HITLTriggerEventFailurePayload(
error="The timeout has passed, and the response has not yet been received.",
error_type="timeout",
)
)
return
resp = await sync_to_async(update_hitl_detail_response)(
ti_id=self.ti_id,
chosen_options=self.defaults,
params_input=self.params,
)
if TYPE_CHECKING:
assert resp.responded_at is not None
self.log.info(
"[HITL] timeout reached before receiving response, fallback to default %s", self.defaults
)
yield TriggerEvent(
HITLTriggerEventSuccessPayload(
chosen_options=self.defaults,
params_input=self.params,
responded_by_user=None,
responded_at=resp.responded_at,
timedout=True,
)
)
return
resp = await sync_to_async(get_hitl_detail_content_detail)(ti_id=self.ti_id)
if resp.response_received and resp.chosen_options:
if TYPE_CHECKING:
assert resp.responded_by_user is not None
assert resp.responded_at is not None
self.log.info(
"[HITL] responded_by=%s (id=%s) options=%s at %s",
resp.responded_by_user.name,
resp.responded_by_user.id,
resp.chosen_options,
resp.responded_at,
)
yield TriggerEvent(
HITLTriggerEventSuccessPayload(
chosen_options=resp.chosen_options,
params_input=resp.params_input or {},
responded_at=resp.responded_at,
responded_by_user=HITLUser(
id=resp.responded_by_user.id,
name=resp.responded_by_user.name,
),
timedout=False,
)
)
return
await asyncio.sleep(self.poke_interval)