TaskInput

Marks a class as a task's input: when the Python Dag file calls the stub task with keyword arguments, each public field receives the argument whose name matches it, ignoring case and underscores. That is the same fold the Go and TypeScript SDKs apply, so one Python signature binds identically in every SDK with nothing declared; ArgName pins a name the fold cannot reach.

public static class ScoreInput implements TaskInput {
  // Pinned to region_code. Or drop it: public String regionCode;
  @ArgName("region_code")
  public String region;

  public double threshold; // binds threshold
}

@Airflow.TaskHandler(dag = "etl", task = "score")
public Result score(Client client, ScoreInput input) { ... }

A TaskInput binds the same way whichever authoring API declares it: as a @Airflow.TaskHandler parameter, as above, or as the input type of an InputTask. A task method may declare at most one TaskInput parameter and, if it does, no other data parameters — the TaskInput owns the whole named-argument surface, so field names and flat positions cannot shift each other.

The class needs a public no-argument constructor and public non-final fields. No two of those fields may claim argument names that differ only in case or underscores, since the fold cannot tell them apart.

A name mismatch in either direction is logged rather than failed: a field nothing supplies keeps its Java default, and an argument no field claims changes nothing the task reads. Once a field has claimed its argument, declare a boxed type when that argument may resolve to nothing.

See also