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"""
This module contains a Google Pub/Sub Hook.
.. spelling::
MessageStoragePolicy
ReceivedMessage
"""
from __future__ import annotations
import warnings
from base64 import b64decode
from typing import Sequence
from uuid import uuid4
from google.api_core.exceptions import AlreadyExists, GoogleAPICallError
from google.api_core.gapic_v1.method import DEFAULT, _MethodDefault
from google.api_core.retry import Retry
from google.cloud.exceptions import NotFound
from google.cloud.pubsub_v1 import PublisherClient, SubscriberClient
from google.cloud.pubsub_v1.types import (
DeadLetterPolicy,
Duration,
ExpirationPolicy,
MessageStoragePolicy,
PushConfig,
ReceivedMessage,
RetryPolicy,
)
from googleapiclient.errors import HttpError
from airflow.compat.functools import cached_property
from airflow.providers.google.common.consts import CLIENT_INFO
from airflow.providers.google.common.hooks.base_google import PROVIDE_PROJECT_ID, GoogleBaseHook
from airflow.version import version
[docs]class PubSubException(Exception):
"""Alias for Exception."""
[docs]class PubSubHook(GoogleBaseHook):
"""
Hook for accessing Google Pub/Sub.
The Google Cloud project against which actions are applied is determined by
the project embedded in the Connection referenced by gcp_conn_id.
"""
def __init__(
self,
gcp_conn_id: str = "google_cloud_default",
delegate_to: str | None = None,
impersonation_chain: str | Sequence[str] | None = None,
) -> None:
super().__init__(
gcp_conn_id=gcp_conn_id,
delegate_to=delegate_to,
impersonation_chain=impersonation_chain,
)
self._client = None
[docs] def get_conn(self) -> PublisherClient:
"""
Retrieves connection to Google Cloud Pub/Sub.
:return: Google Cloud Pub/Sub client object.
"""
if not self._client:
self._client = PublisherClient(credentials=self.get_credentials(), client_info=CLIENT_INFO)
return self._client
@cached_property
[docs] def subscriber_client(self) -> SubscriberClient:
"""
Creates SubscriberClient.
:return: Google Cloud Pub/Sub client object.
"""
return SubscriberClient(credentials=self.get_credentials(), client_info=CLIENT_INFO)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def publish(
self,
topic: str,
messages: list[dict],
project_id: str = PROVIDE_PROJECT_ID,
) -> None:
"""
Publishes messages to a Pub/Sub topic.
:param topic: the Pub/Sub topic to which to publish; do not
include the ``projects/{project}/topics/`` prefix.
:param messages: messages to publish; if the data field in a
message is set, it should be a bytestring (utf-8 encoded)
https://cloud.google.com/pubsub/docs/reference/rpc/google.pubsub.v1#pubsubmessage
:param project_id: Optional, the Google Cloud project ID in which to publish.
If set to None or missing, the default project_id from the Google Cloud connection is used.
"""
self._validate_messages(messages)
publisher = self.get_conn()
topic_path = f"projects/{project_id}/topics/{topic}"
self.log.info("Publish %d messages to topic (path) %s", len(messages), topic_path)
try:
for message in messages:
future = publisher.publish(
topic=topic_path, data=message.get("data", b""), **message.get("attributes", {})
)
future.result()
except GoogleAPICallError as e:
raise PubSubException(f"Error publishing to topic {topic_path}", e)
self.log.info("Published %d messages to topic (path) %s", len(messages), topic_path)
@staticmethod
def _validate_messages(messages) -> None:
for message in messages:
# To warn about broken backward compatibility
# TODO: remove one day
if "data" in message and isinstance(message["data"], str):
try:
b64decode(message["data"])
warnings.warn(
"The base 64 encoded string as 'data' field has been deprecated. "
"You should pass bytestring (utf-8 encoded).",
DeprecationWarning,
stacklevel=4,
)
except ValueError:
pass
if not isinstance(message, dict):
raise PubSubException("Wrong message type. Must be a dictionary.")
if "data" not in message and "attributes" not in message:
raise PubSubException("Wrong message. Dictionary must contain 'data' or 'attributes'.")
if "data" in message and not isinstance(message["data"], bytes):
raise PubSubException("Wrong message. 'data' must be send as a bytestring")
if ("data" not in message and "attributes" in message and not message["attributes"]) or (
"attributes" in message and not isinstance(message["attributes"], dict)
):
raise PubSubException(
"Wrong message. If 'data' is not provided 'attributes' must be a non empty dictionary."
)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def create_topic(
self,
topic: str,
project_id: str = PROVIDE_PROJECT_ID,
fail_if_exists: bool = False,
labels: dict[str, str] | None = None,
message_storage_policy: dict | MessageStoragePolicy = None,
kms_key_name: str | None = None,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> None:
"""
Creates a Pub/Sub topic, if it does not already exist.
:param topic: the Pub/Sub topic name to create; do not
include the ``projects/{project}/topics/`` prefix.
:param project_id: Optional, the Google Cloud project ID in which to create the topic
If set to None or missing, the default project_id from the Google Cloud connection is used.
:param fail_if_exists: if set, raise an exception if the topic
already exists
: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.
"""
publisher = self.get_conn()
topic_path = f"projects/{project_id}/topics/{topic}"
# Add airflow-version label to the topic
labels = labels or {}
labels["airflow-version"] = "v" + version.replace(".", "-").replace("+", "-")
self.log.info("Creating topic (path) %s", topic_path)
try:
publisher.create_topic(
request={
"name": topic_path,
"labels": labels,
"message_storage_policy": message_storage_policy,
"kms_key_name": kms_key_name,
},
retry=retry,
timeout=timeout,
metadata=metadata,
)
except AlreadyExists:
self.log.warning("Topic already exists: %s", topic)
if fail_if_exists:
raise PubSubException(f"Topic already exists: {topic}")
except GoogleAPICallError as e:
raise PubSubException(f"Error creating topic {topic}", e)
self.log.info("Created topic (path) %s", topic_path)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def delete_topic(
self,
topic: str,
project_id: str = PROVIDE_PROJECT_ID,
fail_if_not_exists: bool = False,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> None:
"""
Deletes a Pub/Sub topic if it exists.
:param topic: the Pub/Sub topic name to delete; do not
include the ``projects/{project}/topics/`` prefix.
:param project_id: Optional, the Google Cloud project ID in which to delete the topic.
If set to None or missing, the default project_id from the Google Cloud connection is used.
:param fail_if_not_exists: if set, raise an exception if the topic
does not exist
: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.
"""
publisher = self.get_conn()
topic_path = f"projects/{project_id}/topics/{topic}"
self.log.info("Deleting topic (path) %s", topic_path)
try:
publisher.delete_topic(
request={"topic": topic_path}, retry=retry, timeout=timeout, metadata=metadata or ()
)
except NotFound:
self.log.warning("Topic does not exist: %s", topic_path)
if fail_if_not_exists:
raise PubSubException(f"Topic does not exist: {topic_path}")
except GoogleAPICallError as e:
raise PubSubException(f"Error deleting topic {topic}", e)
self.log.info("Deleted topic (path) %s", topic_path)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def create_subscription(
self,
topic: str,
project_id: str = PROVIDE_PROJECT_ID,
subscription: str | None = None,
subscription_project_id: str | None = None,
ack_deadline_secs: int = 10,
fail_if_exists: bool = False,
push_config: dict | PushConfig | None = None,
retain_acked_messages: bool | None = None,
message_retention_duration: dict | Duration | None = None,
labels: dict[str, str] | None = None,
enable_message_ordering: bool = False,
expiration_policy: dict | ExpirationPolicy | None = None,
filter_: str | None = None,
dead_letter_policy: dict | DeadLetterPolicy | None = None,
retry_policy: dict | RetryPolicy | None = None,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> str:
"""
Creates a Pub/Sub subscription, if it does not already exist.
:param topic: the Pub/Sub topic name that the subscription will be bound
to create; do not include the ``projects/{project}/subscriptions/`` prefix.
:param project_id: Optional, the Google Cloud project ID of the topic that the subscription will be
bound to. If set to None or missing, the default project_id from the Google Cloud connection
is used.
: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 unspecified, ``project_id`` will be used.
:param ack_deadline_secs: Number of seconds that a subscriber has to
acknowledge each message pulled from the subscription
:param fail_if_exists: if set, raise an exception if the topic
already exists
: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.
:return: subscription name which will be the system-generated value if
the ``subscription`` parameter is not supplied
"""
subscriber = self.subscriber_client
if not subscription:
subscription = f"sub-{uuid4()}"
if not subscription_project_id:
subscription_project_id = project_id
# Add airflow-version label to the subscription
labels = labels or {}
labels["airflow-version"] = "v" + version.replace(".", "-").replace("+", "-")
subscription_path = f"projects/{subscription_project_id}/subscriptions/{subscription}"
topic_path = f"projects/{project_id}/topics/{topic}"
self.log.info("Creating subscription (path) %s for topic (path) %a", subscription_path, topic_path)
try:
subscriber.create_subscription(
request={
"name": subscription_path,
"topic": topic_path,
"push_config": push_config,
"ack_deadline_seconds": ack_deadline_secs,
"retain_acked_messages": retain_acked_messages,
"message_retention_duration": message_retention_duration,
"labels": labels,
"enable_message_ordering": enable_message_ordering,
"expiration_policy": expiration_policy,
"filter": filter_,
"dead_letter_policy": dead_letter_policy,
"retry_policy": retry_policy,
},
retry=retry,
timeout=timeout,
metadata=metadata,
)
except AlreadyExists:
self.log.warning("Subscription already exists: %s", subscription_path)
if fail_if_exists:
raise PubSubException(f"Subscription already exists: {subscription_path}")
except GoogleAPICallError as e:
raise PubSubException(f"Error creating subscription {subscription_path}", e)
self.log.info("Created subscription (path) %s for topic (path) %s", subscription_path, topic_path)
return subscription
@GoogleBaseHook.fallback_to_default_project_id
[docs] def delete_subscription(
self,
subscription: str,
project_id: str = PROVIDE_PROJECT_ID,
fail_if_not_exists: bool = False,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> None:
"""
Deletes a Pub/Sub subscription, if it exists.
:param subscription: the Pub/Sub subscription name to delete; do not
include the ``projects/{project}/subscriptions/`` prefix.
:param project_id: Optional, the Google Cloud project ID where the subscription exists
If set to None or missing, the default project_id from the Google Cloud connection is used.
:param fail_if_not_exists: if set, raise an exception if the topic does not exist
: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.
"""
subscriber = self.subscriber_client
# E501
subscription_path = f"projects/{project_id}/subscriptions/{subscription}"
self.log.info("Deleting subscription (path) %s", subscription_path)
try:
subscriber.delete_subscription(
request={"subscription": subscription_path},
retry=retry,
timeout=timeout,
metadata=metadata,
)
except NotFound:
self.log.warning("Subscription does not exist: %s", subscription_path)
if fail_if_not_exists:
raise PubSubException(f"Subscription does not exist: {subscription_path}")
except GoogleAPICallError as e:
raise PubSubException(f"Error deleting subscription {subscription_path}", e)
self.log.info("Deleted subscription (path) %s", subscription_path)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def pull(
self,
subscription: str,
max_messages: int,
project_id: str = PROVIDE_PROJECT_ID,
return_immediately: bool = False,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> list[ReceivedMessage]:
"""
Pulls up to ``max_messages`` messages from Pub/Sub subscription.
:param subscription: the Pub/Sub subscription name to pull from; do not
include the 'projects/{project}/topics/' prefix.
:param max_messages: The maximum number of messages to return from
the Pub/Sub API.
:param project_id: Optional, the Google Cloud project ID where the subscription exists.
If set to None or missing, the default project_id from the Google Cloud connection is used.
:param return_immediately: If set, the Pub/Sub API will immediately
return if no messages are available. Otherwise, the request will
block for an undisclosed, but bounded period of time
: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.
:return: A list of Pub/Sub ReceivedMessage objects each containing
an ``ackId`` property and a ``message`` property, which includes
the base64-encoded message content. See
https://cloud.google.com/pubsub/docs/reference/rpc/google.pubsub.v1#google.pubsub.v1.ReceivedMessage
"""
subscriber = self.subscriber_client
# E501
subscription_path = f"projects/{project_id}/subscriptions/{subscription}"
self.log.info("Pulling max %d messages from subscription (path) %s", max_messages, subscription_path)
try:
response = subscriber.pull(
request={
"subscription": subscription_path,
"max_messages": max_messages,
"return_immediately": return_immediately,
},
retry=retry,
timeout=timeout,
metadata=metadata,
)
result = getattr(response, "received_messages", [])
self.log.info("Pulled %d messages from subscription (path) %s", len(result), subscription_path)
return result
except (HttpError, GoogleAPICallError) as e:
raise PubSubException(f"Error pulling messages from subscription {subscription_path}", e)
@GoogleBaseHook.fallback_to_default_project_id
[docs] def acknowledge(
self,
subscription: str,
project_id: str,
ack_ids: list[str] | None = None,
messages: list[ReceivedMessage] | None = None,
retry: Retry | _MethodDefault = DEFAULT,
timeout: float | None = None,
metadata: Sequence[tuple[str, str]] = (),
) -> None:
"""
Acknowledges the messages associated with the ``ack_ids`` from Pub/Sub subscription.
:param subscription: the Pub/Sub subscription name to delete; do not
include the 'projects/{project}/topics/' prefix.
:param ack_ids: List of ReceivedMessage ackIds from a previous pull response.
Mutually exclusive with ``messages`` argument.
:param messages: List of ReceivedMessage objects to acknowledge.
Mutually exclusive with ``ack_ids`` argument.
:param project_id: Optional, the Google Cloud project name or ID in which to create the topic
If set to None or missing, the default project_id from the Google Cloud connection is used.
: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.
"""
if ack_ids is not None and messages is None:
pass # use ack_ids as is
elif ack_ids is None and messages is not None:
ack_ids = [message.ack_id for message in messages] # extract ack_ids from messages
else:
raise ValueError("One and only one of 'ack_ids' and 'messages' arguments have to be provided")
subscriber = self.subscriber_client
# E501
subscription_path = f"projects/{project_id}/subscriptions/{subscription}"
self.log.info("Acknowledging %d ack_ids from subscription (path) %s", len(ack_ids), subscription_path)
try:
subscriber.acknowledge(
request={"subscription": subscription_path, "ack_ids": ack_ids},
retry=retry,
timeout=timeout,
metadata=metadata,
)
except (HttpError, GoogleAPICallError) as e:
raise PubSubException(
f"Error acknowledging {len(ack_ids)} messages pulled from subscription {subscription_path}",
e,
)
self.log.info("Acknowledged ack_ids from subscription (path) %s", subscription_path)
