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"""Reads and then deletes the message from SQS queue"""
import json
import warnings
from typing import TYPE_CHECKING, Any, Optional, Sequence

from jsonpath_ng import parse
from typing_extensions import Literal

from airflow.exceptions import AirflowException
from import SqsHook
from airflow.sensors.base import BaseSensorOperator

    from airflow.utils.context import Context

[docs]class SqsSensor(BaseSensorOperator): """ Get messages from an Amazon SQS queue and then delete the messages from the queue. If deletion of messages fails an AirflowException is thrown. Otherwise, the messages are pushed through XCom with the key ``messages``. .. seealso:: For more information on how to use this sensor, take a look at the guide: :ref:`howto/sensor:SqsSensor` :param aws_conn_id: AWS connection id :param sqs_queue: The SQS queue url (templated) :param max_messages: The maximum number of messages to retrieve for each poke (templated) :param wait_time_seconds: The time in seconds to wait for receiving messages (default: 1 second) :param visibility_timeout: Visibility timeout, a period of time during which Amazon SQS prevents other consumers from receiving and processing the message. :param message_filtering: Specified how received messages should be filtered. Supported options are: `None` (no filtering, default), `'literal'` (message Body literal match) or `'jsonpath'` (message Body filtered using a JSONPath expression). You may add further methods by overriding the relevant class methods. :param message_filtering_match_values: Optional value/s for the message filter to match on. For example, with literal matching, if a message body matches any of the specified values then it is included. For JSONPath matching, the result of the JSONPath expression is used and may match any of the specified values. :param message_filtering_config: Additional configuration to pass to the message filter. For example with JSONPath filtering you can pass a JSONPath expression string here, such as `'foo[*].baz'`. Messages with a Body which does not match are ignored. :param delete_message_on_reception: Default to `True`, the messages are deleted from the queue as soon as being consumed. Otherwise, the messages remain in the queue after consumption and should be deleted manually. """
[docs] template_fields: Sequence[str] = ('sqs_queue', 'max_messages', 'message_filtering_config')
def __init__( self, *, sqs_queue, aws_conn_id: str = 'aws_default', max_messages: int = 5, wait_time_seconds: int = 1, visibility_timeout: Optional[int] = None, message_filtering: Optional[Literal["literal", "jsonpath"]] = None, message_filtering_match_values: Any = None, message_filtering_config: Any = None, delete_message_on_reception: bool = True, **kwargs, ): super().__init__(**kwargs) self.sqs_queue = sqs_queue self.aws_conn_id = aws_conn_id self.max_messages = max_messages self.wait_time_seconds = wait_time_seconds self.visibility_timeout = visibility_timeout self.message_filtering = message_filtering self.delete_message_on_reception = delete_message_on_reception if message_filtering_match_values is not None: if not isinstance(message_filtering_match_values, set): message_filtering_match_values = set(message_filtering_match_values) self.message_filtering_match_values = message_filtering_match_values if self.message_filtering == 'literal': if self.message_filtering_match_values is None: raise TypeError('message_filtering_match_values must be specified for literal matching') self.message_filtering_config = message_filtering_config self.hook: Optional[SqsHook] = None
[docs] def poke(self, context: 'Context'): """ Check for message on subscribed queue and write to xcom the message with key ``messages`` :param context: the context object :return: ``True`` if message is available or ``False`` """ sqs_conn = self.get_hook().get_conn()'SqsSensor checking for message on queue: %s', self.sqs_queue) receive_message_kwargs = { 'QueueUrl': self.sqs_queue, 'MaxNumberOfMessages': self.max_messages, 'WaitTimeSeconds': self.wait_time_seconds, } if self.visibility_timeout is not None: receive_message_kwargs['VisibilityTimeout'] = self.visibility_timeout response = sqs_conn.receive_message(**receive_message_kwargs) if "Messages" not in response: return False messages = response['Messages'] num_messages = len(messages)"Received %d messages", num_messages) if num_messages and self.message_filtering: messages = self.filter_messages(messages) num_messages = len(messages)"There are %d messages left after filtering", num_messages) if not num_messages: return False if not self.delete_message_on_reception: context['ti'].xcom_push(key='messages', value=messages) return True"Deleting %d messages", num_messages) entries = [ {'Id': message['MessageId'], 'ReceiptHandle': message['ReceiptHandle']} for message in messages ] response = sqs_conn.delete_message_batch(QueueUrl=self.sqs_queue, Entries=entries) if 'Successful' in response: context['ti'].xcom_push(key='messages', value=messages) return True else: raise AirflowException( 'Delete SQS Messages failed ' + str(response) + ' for messages ' + str(messages)
[docs] def get_hook(self) -> SqsHook: """Create and return an SqsHook""" if self.hook: return self.hook self.hook = SqsHook(aws_conn_id=self.aws_conn_id) return self.hook
[docs] def filter_messages(self, messages): if self.message_filtering == 'literal': return self.filter_messages_literal(messages) if self.message_filtering == 'jsonpath': return self.filter_messages_jsonpath(messages) else: raise NotImplementedError('Override this method to define custom filters')
[docs] def filter_messages_literal(self, messages): filtered_messages = [] for message in messages: if message['Body'] in self.message_filtering_match_values: filtered_messages.append(message) return filtered_messages
[docs] def filter_messages_jsonpath(self, messages): jsonpath_expr = parse(self.message_filtering_config) filtered_messages = [] for message in messages: body = message['Body'] # Body is a string, deserialize to an object and then parse body = json.loads(body) results = jsonpath_expr.find(body) if not results: continue if self.message_filtering_match_values is None: filtered_messages.append(message) continue for result in results: if result.value in self.message_filtering_match_values: filtered_messages.append(message) break return filtered_messages
[docs]class SQSSensor(SqsSensor): """ This sensor is deprecated. Please use :class:``. """ def __init__(self, *args, **kwargs): warnings.warn( "This class is deprecated. Please use ``.", DeprecationWarning, stacklevel=2, ) super().__init__(*args, **kwargs)

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