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"""This module contains Google Cloud Pubsub triggers."""

from __future__ import annotations

import asyncio
from typing import TYPE_CHECKING, Any, AsyncIterator, Callable, Sequence

from import PubSubAsyncHook
from airflow.triggers.base import BaseTrigger, TriggerEvent

    from import ReceivedMessage

    from airflow.utils.context import Context

[docs]class PubsubPullTrigger(BaseTrigger): """ Initialize the Pubsub Pull Trigger with needed parameters. :param project_id: the Google Cloud project ID for the subscription (templated) :param subscription: the Pub/Sub subscription name. Do not include the full subscription path. :param max_messages: The maximum number of messages to retrieve per PubSub pull request :param ack_messages: If True, each message will be acknowledged immediately rather than by any downstream tasks :param gcp_conn_id: Reference to google cloud connection id :param messages_callback: (Optional) Callback to process received messages. Its return value will be saved to XCom. If you are pulling large messages, you probably want to provide a custom callback. If not provided, the default implementation will convert `ReceivedMessage` objects into JSON-serializable dicts using `google.protobuf.json_format.MessageToDict` function. :param poke_interval: polling period in seconds to check for the status :param impersonation_chain: Optional service account to impersonate using short-term credentials, or chained list of accounts required to get the access_token of the last account in the list, which will be impersonated in the request. If set as a string, the account must grant the originating account the Service Account Token Creator IAM role. If set as a sequence, the identities from the list must grant Service Account Token Creator IAM role to the directly preceding identity, with first account from the list granting this role to the originating account (templated). """ def __init__( self, project_id: str, subscription: str, max_messages: int, ack_messages: bool, gcp_conn_id: str, messages_callback: Callable[[list[ReceivedMessage], Context], Any] | None = None, poke_interval: float = 10.0, impersonation_chain: str | Sequence[str] | None = None, ): super().__init__() self.project_id = project_id self.subscription = subscription self.max_messages = max_messages self.ack_messages = ack_messages self.messages_callback = messages_callback self.poke_interval = poke_interval self.gcp_conn_id = gcp_conn_id self.impersonation_chain = impersonation_chain self.hook = PubSubAsyncHook()
[docs] def serialize(self) -> tuple[str, dict[str, Any]]: """Serialize PubsubPullTrigger arguments and classpath.""" return ( "", { "project_id": self.project_id, "subscription": self.subscription, "max_messages": self.max_messages, "ack_messages": self.ack_messages, "messages_callback": self.messages_callback, "poke_interval": self.poke_interval, "gcp_conn_id": self.gcp_conn_id, "impersonation_chain": self.impersonation_chain, }, )
[docs] async def run(self) -> AsyncIterator[TriggerEvent]: # type: ignore[override] try: while True: if pulled_messages := await self.hook.pull( project_id=self.project_id, subscription=self.subscription, max_messages=self.max_messages, return_immediately=True, ): if self.ack_messages: await self.message_acknowledgement(pulled_messages) yield TriggerEvent({"status": "success", "message": pulled_messages}) return"Sleeping for %s seconds.", self.poke_interval) await asyncio.sleep(self.poke_interval) except Exception as e: yield TriggerEvent({"status": "error", "message": str(e)}) return
[docs] async def message_acknowledgement(self, pulled_messages): await self.hook.acknowledge( project_id=self.project_id, subscription=self.subscription, messages=pulled_messages, )"Acknowledged ack_ids from subscription %s", self.subscription)

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