ray.util.dask.callbacks.RayDaskCallback._ray_presubmit#

RayDaskCallback._ray_presubmit(task, key, deps) → Any | None[source]#

Run before submitting a Ray task.

If this callback returns a non-None value, Ray does _not_ create a task and uses this value as the would-be task’s result value.

Parameters:

  • task – A Dask task, where the first tuple item is the task function, and the remaining tuple items are the task arguments, which are either the actual argument values, or Dask keys into the deps dictionary whose corresponding values are the argument values.

  • key – The Dask graph key for the given task.

  • deps – The dependencies of this task.

Returns:

Either None, in which case Ray submits a task, or a non-None value, in which case Ray task doesn’t submit a task and uses this return value as the would-be task result value.