Apache Airflow is a platform to programmatically author, schedule, and monitor workflows. It is used to create Directed Acyclic Graphs (DAGs), which are a collection of all tasks you want to run, organized in a way that reflects their relationships and dependencies.
When using Apache Airflow, it's important to understand the different blocks that make up a DAG. One of these blocks includes scheduling instructions.
The scheduling instructions block in a DAG is where you specify the frequency and time frame in which your tasks should run. This block is an essential part of a DAG, as it determines when and how often your tasks will be executed. Without proper scheduling instructions, your DAG will not run at all.
There are several key elements in the scheduling instructions block, including:
- Start Date, which specifies the date and time at which your DAG should start running
- DAG Run Schedule Interval, which determines how often your DAG should run
- Catchup, which specifies whether Airflow should run all past missed runs of your DAG or just the latest one
- Task Instance Timeout, which is the maximum time a task instance should run before timing out
- Task Instance Retries, which is the number of retries a task instance should have before failing
In summary, the scheduling instructions block in Apache Airflow DAG is where you determine when and how often your tasks will run. It is a crucial part of your DAG, and should be given careful consideration to ensure your workflows run smoothly and efficiently.