com.spotify.flo

Interface TaskContext<T,S>

All Superinterfaces:

Serializable

All Known Subinterfaces:

TaskOperator<ContextT,SpecT,ResultT>

All Known Implementing Classes:

BigQueryOperator, BigQueryOutput, TaskContextGeneric, TaskOutput

public interface TaskContext<T,S>
extends Serializable

TaskContext interface for operation objects that will be injected into tasks.

A task context is an object that is aware of the lifecycle of a task and can perform operations before and after the task evaluates. A common use case for task contexts is to be able to integrate 3rd party libraries into Flo in a way that makes them easily accessible to tasks.

Method Summary

Modifier and Type	Method and Description
default void	onFail(Task<?> task, Throwable throwable) Will be called just after a task that is using this task context has failed evaluating.
default void	onSuccess(Task<?> task, S z) Will be called just after a task that is using this task context has successfully evaluated.
default void	preRun(Task<?> task) Will be called just before a task that is using this task context starts evaluating.
T	provide(EvalContext evalContext) Creates a new instance of type T.

Method Detail

provide

T provide(EvalContext evalContext)

Creates a new instance of type T. The given EvalContext will be the evaluation context for the task. The task itself can be accessed through EvalContext.currentTask().

Parameters:

evalContext - The evaluation context in which the current task is being evaluated

Returns:

An instance of the provided task context type

preRun

default void preRun(Task<?> task)

Will be called just before a task that is using this task context starts evaluating.

Parameters:

task - The task being evaluated

onSuccess

default void onSuccess(Task<?> task,
                       S z)

Will be called just after a task that is using this task context has successfully evaluated.

Parameters:

task - The task that evaluated

z - The return value of the evaluated task

onFail

default void onFail(Task<?> task,
                    Throwable throwable)

Will be called just after a task that is using this task context has failed evaluating.

Parameters:

task - The task that evaluated

throwable - The throwable that was thrown, causing the failure