jetty/jetty.project

Review RolloverFileOutputStream locking

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#5,092 创建于 2020年7月29日

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 (6 评论) (0 反应) (0 负责人)Java (3,701 star) (1,913 fork)batch import
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描述

Spawned by #5083.

Jetty version 9.4.x

Description RolloverFileOutputStream locking should be improved/removed.

Currently it locks on a class lock for no reasons, since __rollover is only ever written in the constructor (and thus could be final).

There should be some synchronization between the writes and the scheduled task (so that the file can be swapped without losing log lines), but the class locks seem unnecessary.

贡献者指南

技术栈
java
领域
backendperformance
议题类型
refactor
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。
3
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。
half day
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
Java concurrency basicsUnderstanding of synchronized blocks
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。
40
研究方向
Start by examining the `RolloverFileOutputStream` class, likely in `org.eclipse.jetty.util.log` package. Focus on the ` rollover` field and how it is used in the constructor and the scheduled rollover task. The goal is to remove the unnecessary class level lock and introduce minimal synchronization between writes and the rollover task to prevent log line loss. Look at how the file is opened and rotated, and consider using a private lock object or atomic operations. Check the linked issue #5083 for more context.