Source code for airflow.providers.google.cloud.operators.pubsub

#
# 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.
"""
This module contains Google PubSub operators.

.. spelling::

    MessageStoragePolicy
"""
from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Sequence, Tuple, Union

from google.api_core.gapic_v1.method import DEFAULT, _MethodDefault
from google.api_core.retry import Retry
from google.cloud.pubsub_v1.types import (
    DeadLetterPolicy,
    Duration,
    ExpirationPolicy,
    MessageStoragePolicy,
    PushConfig,
    ReceivedMessage,
    RetryPolicy,
)

from airflow.models import BaseOperator
from airflow.providers.google.cloud.hooks.pubsub import PubSubHook

if TYPE_CHECKING:
    from airflow.utils.context import Context


[docs]class PubSubCreateTopicOperator(BaseOperator): """Create a PubSub topic. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:PubSubCreateTopicOperator` By default, if the topic already exists, this operator will not cause the DAG to fail. :: with DAG('successful DAG') as dag: ( PubSubCreateTopicOperator(project_id='my-project', topic='my_new_topic') >> PubSubCreateTopicOperator(project_id='my-project', topic='my_new_topic') ) The operator can be configured to fail if the topic already exists. :: with DAG('failing DAG') as dag: ( PubSubCreateTopicOperator(project_id='my-project', topic='my_new_topic') >> PubSubCreateTopicOperator( project_id='my-project', topic='my_new_topic', fail_if_exists=True, ) ) Both ``project_id`` and ``topic`` are templated so you can use Jinja templating in their values. :param project_id: Optional, the Google Cloud project ID where the topic will be created. If set to None or missing, the default project_id from the Google Cloud connection is used. :param topic: the topic to create. Do not include the full topic path. In other words, instead of ``projects/{project}/topics/{topic}``, provide only ``{topic}``. (templated) :param gcp_conn_id: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :param labels: Client-assigned labels; see https://cloud.google.com/pubsub/docs/labels :param message_storage_policy: Policy constraining the set of Google Cloud regions where messages published to the topic may be stored. If not present, then no constraints are in effect. Union[Dict, google.cloud.pubsub_v1.types.MessageStoragePolicy] :param kms_key_name: The resource name of the Cloud KMS CryptoKey to be used to protect access to messages published on this topic. The expected format is ``projects/*/locations/*/keyRings/*/cryptoKeys/*``. :param retry: (Optional) A retry object used to retry requests. If None is specified, requests will not be retried. :param timeout: (Optional) The amount of time, in seconds, to wait for the request to complete. Note that if retry is specified, the timeout applies to each individual attempt. :param metadata: (Optional) Additional metadata that is provided to the method. :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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'topic', 'impersonation_chain',
)
[docs] ui_color = '#0273d4'
def __init__( self, *, topic: str, project_id: Optional[str] = None, fail_if_exists: bool = False, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, labels: Optional[Dict[str, str]] = None, message_storage_policy: Union[Dict, MessageStoragePolicy] = None, kms_key_name: Optional[str] = None, retry: Union[Retry, _MethodDefault] = DEFAULT, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = (), impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.project_id = project_id self.topic = topic self.fail_if_exists = fail_if_exists self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.labels = labels self.message_storage_policy = message_storage_policy self.kms_key_name = kms_key_name self.retry = retry self.timeout = timeout self.metadata = metadata self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> None: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) self.log.info("Creating topic %s", self.topic) hook.create_topic( project_id=self.project_id, topic=self.topic, fail_if_exists=self.fail_if_exists, labels=self.labels, message_storage_policy=self.message_storage_policy, kms_key_name=self.kms_key_name, retry=self.retry, timeout=self.timeout, metadata=self.metadata, ) self.log.info("Created topic %s", self.topic)
[docs]class PubSubCreateSubscriptionOperator(BaseOperator): """Create a PubSub subscription. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:PubSubCreateSubscriptionOperator` By default, the subscription will be created in ``project_id``. If ``subscription_project_id`` is specified and the Google Cloud credentials allow, the Subscription can be created in a different project from its topic. By default, if the subscription already exists, this operator will not cause the DAG to fail. However, the topic must exist in the project. :: with DAG('successful DAG') as dag: ( PubSubCreateSubscriptionOperator( project_id='my-project', topic='my-topic', subscription='my-subscription' ) >> PubSubCreateSubscriptionOperator( project_id='my-project', topic='my-topic', subscription='my-subscription', ) ) The operator can be configured to fail if the subscription already exists. :: with DAG('failing DAG') as dag: ( PubSubCreateSubscriptionOperator( project_id='my-project', topic='my-topic', subscription='my-subscription', ) >> PubSubCreateSubscriptionOperator( project_id='my-project', topic='my-topic', subscription='my-subscription', fail_if_exists=True, ) ) Finally, subscription is not required. If not passed, the operator will generated a universally unique identifier for the subscription's name. :: with DAG('DAG') as dag: PubSubCreateSubscriptionOperator(project_id='my-project', topic='my-topic') ``project_id``, ``topic``, ``subscription``, ``subscription_project_id`` and ``impersonation_chain`` are templated so you can use Jinja templating in their values. :param project_id: Optional, the Google Cloud project ID where the topic exists. If set to None or missing, the default project_id from the Google Cloud connection is used. :param topic: the topic to create. Do not include the full topic path. In other words, instead of ``projects/{project}/topics/{topic}``, provide only ``{topic}``. (templated) :param subscription: the Pub/Sub subscription name. If empty, a random name will be generated using the uuid module :param subscription_project_id: the Google Cloud project ID where the subscription will be created. If empty, ``topic_project`` will be used. :param ack_deadline_secs: Number of seconds that a subscriber has to acknowledge each message pulled from the subscription :param gcp_conn_id: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :param push_config: If push delivery is used with this subscription, this field is used to configure it. An empty ``pushConfig`` signifies that the subscriber will pull and ack messages using API methods. :param retain_acked_messages: Indicates whether to retain acknowledged messages. If true, then messages are not expunged from the subscription's backlog, even if they are acknowledged, until they fall out of the ``message_retention_duration`` window. This must be true if you would like to Seek to a timestamp. :param message_retention_duration: How long to retain unacknowledged messages in the subscription's backlog, from the moment a message is published. If ``retain_acked_messages`` is true, then this also configures the retention of acknowledged messages, and thus configures how far back in time a ``Seek`` can be done. Defaults to 7 days. Cannot be more than 7 days or less than 10 minutes. :param labels: Client-assigned labels; see https://cloud.google.com/pubsub/docs/labels :param enable_message_ordering: If true, messages published with the same ordering_key in PubsubMessage will be delivered to the subscribers in the order in which they are received by the Pub/Sub system. Otherwise, they may be delivered in any order. :param expiration_policy: A policy that specifies the conditions for this subscription’s expiration. A subscription is considered active as long as any connected subscriber is successfully consuming messages from the subscription or is issuing operations on the subscription. If expiration_policy is not set, a default policy with ttl of 31 days will be used. The minimum allowed value for expiration_policy.ttl is 1 day. :param filter_: An expression written in the Cloud Pub/Sub filter language. If non-empty, then only PubsubMessages whose attributes field matches the filter are delivered on this subscription. If empty, then no messages are filtered out. :param dead_letter_policy: A policy that specifies the conditions for dead lettering messages in this subscription. If dead_letter_policy is not set, dead lettering is disabled. :param retry_policy: A policy that specifies how Pub/Sub retries message delivery for this subscription. If not set, the default retry policy is applied. This generally implies that messages will be retried as soon as possible for healthy subscribers. RetryPolicy will be triggered on NACKs or acknowledgement deadline exceeded events for a given message. :param retry: (Optional) A retry object used to retry requests. If None is specified, requests will not be retried. :param timeout: (Optional) The amount of time, in seconds, to wait for the request to complete. Note that if retry is specified, the timeout applies to each individual attempt. :param metadata: (Optional) Additional metadata that is provided to the method. :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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'topic', 'subscription', 'subscription_project_id', 'impersonation_chain',
)
[docs] ui_color = '#0273d4'
def __init__( self, *, topic: str, project_id: Optional[str] = None, subscription: Optional[str] = None, subscription_project_id: Optional[str] = None, ack_deadline_secs: int = 10, fail_if_exists: bool = False, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, push_config: Optional[Union[Dict, PushConfig]] = None, retain_acked_messages: Optional[bool] = None, message_retention_duration: Optional[Union[Dict, Duration]] = None, labels: Optional[Dict[str, str]] = None, enable_message_ordering: bool = False, expiration_policy: Optional[Union[Dict, ExpirationPolicy]] = None, filter_: Optional[str] = None, dead_letter_policy: Optional[Union[Dict, DeadLetterPolicy]] = None, retry_policy: Optional[Union[Dict, RetryPolicy]] = None, retry: Union[Retry, _MethodDefault] = DEFAULT, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = (), impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.project_id = project_id self.topic = topic self.subscription = subscription self.subscription_project_id = subscription_project_id self.ack_deadline_secs = ack_deadline_secs self.fail_if_exists = fail_if_exists self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.push_config = push_config self.retain_acked_messages = retain_acked_messages self.message_retention_duration = message_retention_duration self.labels = labels self.enable_message_ordering = enable_message_ordering self.expiration_policy = expiration_policy self.filter_ = filter_ self.dead_letter_policy = dead_letter_policy self.retry_policy = retry_policy self.retry = retry self.timeout = timeout self.metadata = metadata self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> str: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) self.log.info("Creating subscription for topic %s", self.topic) result = hook.create_subscription( project_id=self.project_id, topic=self.topic, subscription=self.subscription, subscription_project_id=self.subscription_project_id, ack_deadline_secs=self.ack_deadline_secs, fail_if_exists=self.fail_if_exists, push_config=self.push_config, retain_acked_messages=self.retain_acked_messages, message_retention_duration=self.message_retention_duration, labels=self.labels, enable_message_ordering=self.enable_message_ordering, expiration_policy=self.expiration_policy, filter_=self.filter_, dead_letter_policy=self.dead_letter_policy, retry_policy=self.retry_policy, retry=self.retry, timeout=self.timeout, metadata=self.metadata, ) self.log.info("Created subscription for topic %s", self.topic) return result
[docs]class PubSubDeleteTopicOperator(BaseOperator): """Delete a PubSub topic. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:PubSubDeleteTopicOperator` By default, if the topic does not exist, this operator will not cause the DAG to fail. :: with DAG('successful DAG') as dag: PubSubDeleteTopicOperator(project_id='my-project', topic='non_existing_topic') The operator can be configured to fail if the topic does not exist. :: with DAG('failing DAG') as dag: PubSubDeleteTopicOperator( project_id='my-project', topic='non_existing_topic', fail_if_not_exists=True, ) Both ``project_id`` and ``topic`` are templated so you can use Jinja templating in their values. :param project_id: Optional, the Google Cloud project ID in which to work (templated). If set to None or missing, the default project_id from the Google Cloud connection is used. :param topic: the topic to delete. Do not include the full topic path. In other words, instead of ``projects/{project}/topics/{topic}``, provide only ``{topic}``. (templated) :param fail_if_not_exists: If True and the topic does not exist, fail the task :param gcp_conn_id: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :param retry: (Optional) A retry object used to retry requests. If None is specified, requests will not be retried. :param timeout: (Optional) The amount of time, in seconds, to wait for the request to complete. Note that if retry is specified, the timeout applies to each individual attempt. :param metadata: (Optional) Additional metadata that is provided to the method. :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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'topic', 'impersonation_chain',
)
[docs] ui_color = '#cb4335'
def __init__( self, *, topic: str, project_id: Optional[str] = None, fail_if_not_exists: bool = False, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, retry: Union[Retry, _MethodDefault] = DEFAULT, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = (), impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.project_id = project_id self.topic = topic self.fail_if_not_exists = fail_if_not_exists self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.retry = retry self.timeout = timeout self.metadata = metadata self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> None: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) self.log.info("Deleting topic %s", self.topic) hook.delete_topic( project_id=self.project_id, topic=self.topic, fail_if_not_exists=self.fail_if_not_exists, retry=self.retry, timeout=self.timeout, metadata=self.metadata, ) self.log.info("Deleted topic %s", self.topic)
[docs]class PubSubDeleteSubscriptionOperator(BaseOperator): """Delete a PubSub subscription. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:PubSubDeleteSubscriptionOperator` By default, if the subscription does not exist, this operator will not cause the DAG to fail. :: with DAG('successful DAG') as dag: PubSubDeleteSubscriptionOperator(project_id='my-project', subscription='non-existing') The operator can be configured to fail if the subscription already exists. :: with DAG('failing DAG') as dag: PubSubDeleteSubscriptionOperator( project_id='my-project', subscription='non-existing', fail_if_not_exists=True, ) ``project_id``, and ``subscription`` are templated so you can use Jinja templating in their values. :param project_id: Optional, the Google Cloud project ID in which to work (templated). If set to None or missing, the default project_id from the Google Cloud connection is used. :param subscription: the subscription to delete. Do not include the full subscription path. In other words, instead of ``projects/{project}/subscription/{subscription}``, provide only ``{subscription}``. (templated) :param fail_if_not_exists: If True and the subscription does not exist, fail the task :param gcp_conn_id: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :param retry: (Optional) A retry object used to retry requests. If None is specified, requests will not be retried. :param timeout: (Optional) The amount of time, in seconds, to wait for the request to complete. Note that if retry is specified, the timeout applies to each individual attempt. :param metadata: (Optional) Additional metadata that is provided to the method. :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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'subscription', 'impersonation_chain',
)
[docs] ui_color = '#cb4335'
def __init__( self, *, subscription: str, project_id: Optional[str] = None, fail_if_not_exists: bool = False, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, retry: Union[Retry, _MethodDefault] = DEFAULT, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = (), impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.project_id = project_id self.subscription = subscription self.fail_if_not_exists = fail_if_not_exists self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.retry = retry self.timeout = timeout self.metadata = metadata self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> None: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) self.log.info("Deleting subscription %s", self.subscription) hook.delete_subscription( project_id=self.project_id, subscription=self.subscription, fail_if_not_exists=self.fail_if_not_exists, retry=self.retry, timeout=self.timeout, metadata=self.metadata, ) self.log.info("Deleted subscription %s", self.subscription)
[docs]class PubSubPublishMessageOperator(BaseOperator): """Publish messages to a PubSub topic. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:PubSubPublishMessageOperator` Each Task publishes all provided messages to the same topic in a single Google Cloud project. If the topic does not exist, this task will fail. :: m1 = {'data': b'Hello, World!', 'attributes': {'type': 'greeting'} } m2 = {'data': b'Knock, knock'} m3 = {'attributes': {'foo': ''}} t1 = PubSubPublishMessageOperator( project_id='my-project', topic='my_topic', messages=[m1, m2, m3], create_topic=True, dag=dag, ) ``project_id``, ``topic``, and ``messages`` are templated so you can use Jinja templating in their values. :param project_id: Optional, the Google Cloud project ID in which to work (templated). If set to None or missing, the default project_id from the Google Cloud connection is used. :param topic: the topic to which to publish. Do not include the full topic path. In other words, instead of ``projects/{project}/topics/{topic}``, provide only ``{topic}``. (templated) :param messages: a list of messages to be published to the topic. Each message is a dict with one or more of the following keys-value mappings: * 'data': a bytestring (utf-8 encoded) * 'attributes': {'key1': 'value1', ...} Each message must contain at least a non-empty 'data' value or an attribute dict with at least one key (templated). See https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage :param gcp_conn_id: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'topic', 'messages', 'impersonation_chain',
)
[docs] ui_color = '#0273d4'
def __init__( self, *, topic: str, messages: List, project_id: Optional[str] = None, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.project_id = project_id self.topic = topic self.messages = messages self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> None: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) self.log.info("Publishing to topic %s", self.topic) hook.publish(project_id=self.project_id, topic=self.topic, messages=self.messages) self.log.info("Published to topic %s", self.topic)
[docs]class PubSubPullOperator(BaseOperator): """Pulls messages from a PubSub subscription and passes them through XCom. If the queue is empty, returns empty list - never waits for messages. If you do need to wait, please use :class:`airflow.providers.google.cloud.sensors.PubSubPullSensor` instead. .. seealso:: For more information on how to use this operator and the PubSubPullSensor, take a look at the guide: :ref:`howto/operator:PubSubPullSensor` This operator will pull up to ``max_messages`` messages from the specified PubSub subscription. When the subscription returns messages, the messages will be returned immediately from the operator and passed through XCom for downstream tasks. If ``ack_messages`` is set to True, messages will be immediately acknowledged before being returned, otherwise, downstream tasks will be responsible for acknowledging them. ``project_id `` and ``subscription`` are templated so you can use Jinja templating in their values. :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: The connection ID to use connecting to Google Cloud. :param delegate_to: The account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :param messages_callback: (Optional) Callback to process received messages. It's 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 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). """
[docs] template_fields: Sequence[str] = ( 'project_id', 'subscription', 'impersonation_chain',
) def __init__( self, *, project_id: str, subscription: str, max_messages: int = 5, ack_messages: bool = False, messages_callback: Optional[Callable[[List[ReceivedMessage], "Context"], Any]] = None, gcp_conn_id: str = 'google_cloud_default', delegate_to: Optional[str] = None, impersonation_chain: Optional[Union[str, Sequence[str]]] = None, **kwargs, ) -> None: super().__init__(**kwargs) self.gcp_conn_id = gcp_conn_id self.delegate_to = delegate_to self.project_id = project_id self.subscription = subscription self.max_messages = max_messages self.ack_messages = ack_messages self.messages_callback = messages_callback self.impersonation_chain = impersonation_chain
[docs] def execute(self, context: 'Context') -> list: hook = PubSubHook( gcp_conn_id=self.gcp_conn_id, delegate_to=self.delegate_to, impersonation_chain=self.impersonation_chain, ) pulled_messages = hook.pull( project_id=self.project_id, subscription=self.subscription, max_messages=self.max_messages, return_immediately=True, ) handle_messages = self.messages_callback or self._default_message_callback ret = handle_messages(pulled_messages, context) if pulled_messages and self.ack_messages: hook.acknowledge( project_id=self.project_id, subscription=self.subscription, messages=pulled_messages, ) return ret
def _default_message_callback( self, pulled_messages: List[ReceivedMessage], context: "Context", ) -> list: """ This method can be overridden by subclasses or by `messages_callback` constructor argument. This default implementation converts `ReceivedMessage` objects into JSON-serializable dicts. :param pulled_messages: messages received from the topic. :param context: same as in `execute` :return: value to be saved to XCom. """ messages_json = [ReceivedMessage.to_dict(m) for m in pulled_messages] return messages_json

Was this entry helpful?