jetty/jetty.project

Review RolloverFileOutputStream locking

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#5,092 opened on Jul 29, 2020

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Description

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.

Contributor guide

Research direction
Examine the RolloverFileOutputStream class to understand the current locking mechanism using class locks, and propose a change to use instance level synchronization or lock free approach to remove unnecessary class level locking while ensuring thread safety during log file rotation.
Tech stack
java
Domain
backend
Issue type
Refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Java
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50