akka/akka-core

Convenience for attributes on Sink

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#30,199 创建于 2021年4月22日

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 (5 评论) (0 反应) (0 负责人)Scala (13,277 star) (3,547 fork)batch import
1 - triagedhelp wantedt:stream

描述

When working on https://github.com/akka/akka-persistence-cassandra/pull/888 I realized that it wasn't obvious how to set a dispatcher all the way to the Sink (and not introduce async boundary).

My first thought, when I didn't realize that the Sink is also involved, was:

.map(stuff)
.withAttributes(ActorAttributes.dispatcher(theDispatcher))
.runWith(Sink.ignore)

but it should be:

.map(stuff)
.toMat(Sink.ignore)(Keep.right)
.withAttributes(ActorAttributes.dispatcher(theDispatcher))
.run()

贡献者指南

技术栈
scala
领域
backend
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
2
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
basic Akka Streams knowledge
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
70
研究方向
The issue requests adding a convenience method for applying attributes directly on `Sink`, similar to how `Flow` already supports `withAttributes`. The main work involves adding a method to `Sink` in the Scala and Java DSL (e.g., `akka stream/src/main/scala/akka/stream/scaladsl/Sink.scala` and the Java counterpart). The linked PR #888 provides context for the use case. Review existing attribute handling in `Flow` and ensure the new method returns a `Sink` with the specified attributes without introducing an async boundary.