The TaskFlow API in Airflow 2.0 simplifies passing data with XComs. This is particularly useful when dealing with large or complex data types. Implementing a custom backend involves subclassing BaseXCom and overriding serialization methods. Remember that XComs are cleared on task retries to maintain idempotence.Īirflow allows the use of custom XCom backends to extend functionality.Avoid storing sensitive information in XComs use Airflow Connections to manage credentials securely.Use XComs for small data payloads for larger files, consider using external storage like S3 or HDFS.Value = task_instance.xcom_pull(key='my_key', task_ids='task_id') To pull a specific key from XCom, specify the key parameter:.Values = task_instance.xcom_pull(task_ids=) For pulling from multiple tasks, pass a list to task_ids:.Value = task_instance.xcom_pull(task_ids='task_id') To pull a value from a specific task, use:.By default, values are pushed to an XCom key named return_value, which xcom_pull can retrieve without specifying a key. The xcom_pull method is used to retrieve values from XComs, which are pushed by other tasks using xcom_push or by returning values from operators or functions. Here's a comprehensive guide to using xcom_pull effectively in your workflows.

It allows tasks to exchange metadata or small amounts of data that can be serialized as JSON.

Remember that many operators automatically push results to XCom under the return_value key.īy following these guidelines and utilizing the xcom_push and xcom_pull methods effectively, you can enhance data sharing between tasks in your Airflow DAGs.Īpache Airflow's xcom_pull function is a key feature for sharing data between tasks within a DAG.

Avoid storing sensitive information in XComs use Airflow Connections instead.

Use XComs for small amounts of data for larger data, consider using external storage like S3 or HDFS.XComs can also be used in Jinja templates for dynamic task configuration: SELECT * FROM Task_instance.xcom_push(key='file_path', value='/path/to/s3/data.csv')ĭownstream tasks can retrieve this data using xcom_pull: # Pull data from XCom using the keyįile_path = task_instance.xcom_pull(key='file_path', task_ids='upstream_task_id') To push data to XCom within a task, use the xcom_push method: # Push data to XCom with a unique key This is particularly useful for sharing small pieces of data such as file paths or configuration parameters. Proper configuration and placement of the custom backend code are essential for successful deployment in these environments.Īpache Airflow's xcom_push method allows tasks to communicate by pushing messages to XComs, which can then be pulled by downstream tasks. Debugging issues, especially in Kubernetes deployments, often requires timely access to container logs. When working with containers or Kubernetes, ensuring that a custom XCom backend is properly initialized can be challenging. This flexibility allows for customization to fit specific use cases, such as optimizing performance for large or complex data types. Additionally, the TaskFlow API simplifies data passing between tasks using implicit XComs, further streamlining the process.Ĭustom XCom backends can be implemented by subclassing BaseXCom and overriding methods like serialize_value, deserialize_value, and clear. This is where XComs prove invaluable, allowing for communication between tasks regardless of their execution environment. Instead, Airflow's Connections should be used to securely store and retrieve such credentials.Īirflow's distributed nature means tasks may execute on different workers or machines. It's crucial to avoid storing sensitive information such as passwords or tokens in tasks. For instance, a task can push the location of processed data stored in S3 to XCom, and downstream tasks can pull this location to access the data. To facilitate the exchange of data between tasks, Airflow provides the xcom_push and xcom_pull methods. While XComs can hold any serializable value, they are intended for small data payloads and should not be used to pass large objects like dataframes. They are identified by a unique key, as well as the task_id and dag_id from which they originate. XComs, or 'cross-communications', are a key feature in Apache Airflow that enable tasks to exchange messages or small amounts of data.

Airflow xcom push example