airflow sqs 源码

airflow sqs 代码

文件路径：/airflow/providers/amazon/aws/sensors/sqs.py

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"""Reads and then deletes the message from SQS queue"""
from __future__ import annotations

import json
from typing import TYPE_CHECKING, Any, Collection, Sequence

from jsonpath_ng import parse
from typing_extensions import Literal

from airflow.exceptions import AirflowException
from airflow.providers.amazon.aws.hooks.base_aws import BaseAwsConnection
from airflow.providers.amazon.aws.hooks.sqs import SqsHook
from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context


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``.

    By default,the sensor performs one and only one SQS call per poke, which limits the result to
    a maximum of 10 messages. However, the total number of SQS API calls per poke can be controlled
    by num_batches param.

    .. 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 num_batches: The number of times the sensor will call the SQS API to receive messages (default: 1)
    :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.

    """

    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,
        num_batches: int = 1,
        wait_time_seconds: int = 1,
        visibility_timeout: int | None = None,
        message_filtering: Literal["literal", "jsonpath"] | None = 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.num_batches = num_batches
        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: SqsHook | None = None

    def poll_sqs(self, sqs_conn: BaseAwsConnection) -> Collection:
        """
        Poll SQS queue to retrieve messages.

        :param sqs_conn: SQS connection
        :return: A list of messages retrieved from SQS
        """
        self.log.info('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 []

        messages = response['Messages']
        num_messages = len(messages)
        self.log.info("Received %d messages", num_messages)

        if num_messages and self.message_filtering:
            messages = self.filter_messages(messages)
            num_messages = len(messages)
            self.log.info("There are %d messages left after filtering", num_messages)
        return messages

    def poke(self, context: Context):
        """
        Check subscribed queue for messages and write them to xcom with the ``messages`` key.

        :param context: the context object
        :return: ``True`` if message is available or ``False``
        """
        sqs_conn = self.get_hook().get_conn()

        message_batch: list[Any] = []

        # perform multiple SQS call to retrieve messages in series
        for _ in range(self.num_batches):
            messages = self.poll_sqs(sqs_conn=sqs_conn)

            if not len(messages):
                continue

            message_batch.extend(messages)

            if self.delete_message_on_reception:

                self.log.info("Deleting %d messages", len(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' not in response:
                    raise AirflowException(
                        'Delete SQS Messages failed ' + str(response) + ' for messages ' + str(messages)
                    )
        if not len(message_batch):
            return False

        context['ti'].xcom_push(key='messages', value=message_batch)
        return True

    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

    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')

    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

    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

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