Astronomer - Apache Airflow 3 Fundamentals DAG Authoring Study Guide

4: Dependencies, branching, trigger rules, task groups, and setup/teardown

This chapter wires individual tasks into a working graph. It covers the full dependency-expression surface (bit-shift operators, `chain()`, `cross_downstream()`, `set_upstream`/`set_downstream`, labeled edges via `EdgeModifier` and `Label`), the two conditional-flow primitives (`@task.branch` versus `@task.short_circuit`), the ten trigger rules and the correct rule for a post-branch join, task groups as the successor to the removed SubDAG pattern, and setup/teardown tasks that bind a resource lifecycle around a block of work.