micrometer-metrics/micrometer

Add cache utilization to basic cache metrics

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#4,321 opened on Nov 7, 2023

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help wanted

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Description

Issue #393 defines some standard cache metrics. However it lacks the cache utilization (in percent), that cannot be calculated from the existing exposed metrics either.

Monitoring the cache utilization is required to trigger early alerts to have enough time for a reconfiguration before the cache actually runs full, starts to evict elements and potentially slows down the system.

Contributor guide

Research direction
Implement a new metric 'cache.utilization' that reports the current utilization percentage of a cache. Use the existing cache metrics infrastructure from issue #393 as a template. Ensure it calculates (currentSize / maxSize) * 100 for caches that support maximum size. Provide implementations for common cache implementations (Caffeine, JCache, etc.).
Tech stack
java
Domain
backendobservability
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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
JavaMicrometer basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60