AWS Step Functions¶

AWS Step Functions makes it easy to coordinate the components of distributed applications as a series of steps in a visual workflow. You can quickly build and run state machines to execute the steps of your application in a reliable and scalable fashion.

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 of Airflow®
Setup Connection.

Generic Parameters¶

aws_conn_id

Reference to Amazon Web Services Connection ID. If this parameter is set to None then the default boto3 behaviour is used without a connection lookup. Otherwise use the credentials stored in the Connection. Default: aws_default

region_name

AWS Region Name. If this parameter is set to None or omitted then region_name from AWS Connection Extra Parameter will be used. Otherwise use the specified value instead of the connection value. Default: None

verify

Whether or not to verify SSL certificates.

False - Do not validate SSL certificates.
path/to/cert/bundle.pem - A filename of the CA cert bundle to use. You can specify this argument if you want to use a different CA cert bundle than the one used by botocore.

If this parameter is set to None or is omitted then verify from AWS Connection Extra Parameter will be used. Otherwise use the specified value instead of the connection value. Default: None

botocore_config

The provided dictionary is used to construct a botocore.config.Config. This configuration can be used to configure Avoid Throttling exceptions, timeouts, etc.

Example, for more detail about parameters please have a look botocore.config.Config¶

{
    "signature_version": "unsigned",
    "s3": {
        "us_east_1_regional_endpoint": True,
    },
    "retries": {
      "mode": "standard",
      "max_attempts": 10,
    },
    "connect_timeout": 300,
    "read_timeout": 300,
    "tcp_keepalive": True,
}

If this parameter is set to None or omitted then config_kwargs from AWS Connection Extra Parameter will be used. Otherwise use the specified value instead of the connection value. Default: None

Note

Specifying an empty dictionary, {}, will overwrite the connection configuration for botocore.config.Config

Operators¶

Start an AWS Step Functions state machine execution¶

To start a new AWS Step Functions state machine execution you can use StepFunctionStartExecutionOperator. You can also run this operator in deferrable mode by setting deferrable param to True.

tests/system/amazon/aws/example_step_functions.py

start_execution = StepFunctionStartExecutionOperator(
    task_id="start_execution", state_machine_arn=state_machine_arn
)

Get an AWS Step Functions execution output¶

To fetch the output from an AWS Step Function state machine execution you can use StepFunctionGetExecutionOutputOperator.

tests/system/amazon/aws/example_step_functions.py

get_execution_output = StepFunctionGetExecutionOutputOperator(
    task_id="get_execution_output", execution_arn=execution_arn
)

Sensors¶

Wait on an AWS Step Functions state machine execution state¶

To wait on the state of an AWS Step Function state machine execution until it reaches a terminal state you can use StepFunctionExecutionSensor.

tests/system/amazon/aws/example_step_functions.py

wait_for_execution = StepFunctionExecutionSensor(
    task_id="wait_for_execution", execution_arn=execution_arn
)

References¶

AWS boto3 library documentation for Step Functions