Model/utilities/aws_lambda/subtask_handler.py
2026-05-20 13:21:11 +00:00

102 lines
3.7 KiB
Python

"""@subtask_handler decorator for Lambdas that operate on existing SubTasks.
Translates an AWS Lambda invocation (SQS-shaped or direct) into
TaskOrchestrator.run_subtask(...) calls.
"""
import json
import logging
import os
from contextlib import AbstractContextManager
from functools import wraps
from typing import Any, Callable, Optional, cast
from urllib.parse import quote
from utilities.aws_lambda.default_orchestrator import default_orchestrator
from utilities.aws_lambda.subtask_trigger_body import SubtaskTriggerBody
from orchestration.task_orchestrator import TaskOrchestrator
logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)
OrchestratorCM = Callable[[], AbstractContextManager[TaskOrchestrator]]
def subtask_handler(
*,
orchestrator_cm: Optional[OrchestratorCM] = None,
) -> Callable[[Callable[..., Any]], Callable[..., Any]]:
"""Run the wrapped function as the body of an existing SubTask.
For each record, validates the body via SubtaskTriggerBody (must contain
task_id and sub_task_id), then runs the function inside
orchestrator.run_subtask(...). The orchestrator owns the start/complete/
fail lifecycle and cascades status into the parent Task. On failure the
underlying exception propagates after the SubTask is marked FAILED.
"""
factory = orchestrator_cm or default_orchestrator
def decorator(func: Callable[..., Any]) -> Callable[..., Any]:
@wraps(func)
def wrapper(event: dict[str, Any], context: Any) -> None:
cloud_logs_url = _cloudwatch_url()
with factory() as orchestrator:
for record in _records(event):
body = _parse_body(record)
trigger = SubtaskTriggerBody.model_validate(body)
logger.info("Running subtask %s", trigger.sub_task_id)
try:
orchestrator.run_subtask(
trigger.sub_task_id,
work=lambda body=body, o=orchestrator: func(
body, context, o
),
cloud_logs_url=cloud_logs_url,
)
except Exception:
logger.exception(
"Subtask %s failed", trigger.sub_task_id
)
raise
logger.info("Subtask %s completed", trigger.sub_task_id)
return wrapper
return decorator
def _parse_body(record: dict[str, Any]) -> dict[str, Any]:
raw = record.get("body", record)
if isinstance(raw, str):
try:
parsed = json.loads(raw)
except json.JSONDecodeError:
return {}
return cast(dict[str, Any], parsed) if isinstance(parsed, dict) else {}
if isinstance(raw, dict):
return cast(dict[str, Any], raw)
return {}
def _records(event: dict[str, Any]) -> list[dict[str, Any]]:
raw_records = event.get("Records")
if isinstance(raw_records, list):
return [r for r in cast(list[Any], raw_records) if isinstance(r, dict)]
return [event]
def _console_encode(value: str) -> str:
return quote(value, safe="").replace("%", "$25")
def _cloudwatch_url() -> Optional[str]:
region = os.environ.get("AWS_REGION")
log_group = os.environ.get("AWS_LAMBDA_LOG_GROUP_NAME")
log_stream = os.environ.get("AWS_LAMBDA_LOG_STREAM_NAME")
if not (region and log_group and log_stream):
return None
return (
f"https://{region}.console.aws.amazon.com/cloudwatch/home"
f"?region={region}#logsV2:log-groups/log-group/"
f"{_console_encode(log_group)}/log-events/{_console_encode(log_stream)}"
)