Amazon SQS¶
Amazon Simple Queue Service (SQS) is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications. SQS eliminates the complexity and overhead associated with managing and operating message-oriented middleware, and empowers developers to focus on differentiating work. Using SQS, you can send, store, and receive messages between software components at any volume, without losing messages or requiring other services to be available.
Prerequisite Tasks¶
To use these operators, you must do a few things:
Create necessary resources using AWS Console or AWS CLI.
Install API libraries via pip.
pip install 'apache-airflow[amazon]'Detailed information is available Installation
Operators¶
Publish a message to an Amazon SQS queue¶
To publish a message to an Amazon SQS queue you can use the
SqsPublishOperator
In the following example, the task publish_to_queue publishes a message containing
the task instance and the execution date to a queue with a default name of Airflow-Example-Queue.
publish_to_queue_1 = SqsPublishOperator(
task_id="publish_to_queue_1",
sqs_queue=sqs_queue,
message_content="{{ task_instance }}-{{ logical_date }}",
)
publish_to_queue_2 = SqsPublishOperator(
task_id="publish_to_queue_2",
sqs_queue=sqs_queue,
message_content="{{ task_instance }}-{{ logical_date }}",
)
Sensors¶
Read messages from an Amazon SQS queue¶
To read messages from an Amazon SQS queue until exhausted use the
SqsSensor
read_from_queue = SqsSensor(
task_id="read_from_queue",
sqs_queue=sqs_queue,
)
# Retrieve multiple batches of messages from SQS.
# The SQS API only returns a maximum of 10 messages per poll.
read_from_queue_in_batch = SqsSensor(
task_id="read_from_queue_in_batch",
sqs_queue=sqs_queue,
# Get maximum 10 messages each poll
max_messages=10,
# Combine 3 polls before returning results
num_batches=3,
)