[BUG] Scale rule deletion does not evict entries from ScaleRuleCache

[juicewcode]

Description

ScaleRuleServiceImpl.delete deletes scale rules from the database by their primary keys, but passes those primary keys
directly to ScaleRuleCache for cache eviction.

However, ScaleRuleCache stores rules with metricName as the cache key. As a result, the cache attempts to remove
entries by rule ID while its keys are metric names. Unless a rule ID happens to equal its metric name, the deleted rule
remains in the cache.

Location

shenyu-admin/src/main/java/org/apache/shenyu/admin/service/impl/ScaleRuleServiceImpl.java

/**
   * delete rules.
   *
   * @param ids primary key
   * @return rows int
   */
public int delete(final List<String> ids) {
    int rows = scaleRuleMapper.delete(ids);
    if (rows > 0) {
        scaleRuleCache.removeRulesFromCache(ids);
    }
    return rows;
}

shenyu-admin/src/main/java/org/apache/shenyu/admin/scale/monitor/subject/cache/ScaleRuleCache.java

 public void addOrUpdateRuleToCache(final ScaleRuleDO rule) {
     ruleCache.put(rule.getMetricName(), rule);
 }

 public void removeRulesFromCache(final List<String> metricNames) {
     metricNames.forEach(ruleCache::remove);
 }

Suggested fix

Keep the cache keyed by metricName, but evict rules by comparing the supplied primary keys with ScaleRuleDO.getId().

For example, introduce a method with explicit semantics:

public void removeRulesByIdsFromCache(final List<String> ids) {
    final Set<String> idSet = new HashSet<>(ids);
    ruleCache.forEach((metricName, rule) -> {
        if (idSet.contains(rule.getId())) {
            ruleCache.remove(metricName, rule);
        }
    });
}

Then update ScaleRuleServiceImpl.delete to call:

scaleRuleCache.removeRulesByIdsFromCache(ids);

[github-actions]

👋 Hello @yuluo-yx

A new issue has been opened by @juicewcode:

• Title: [BUG] Scale rule deletion does not evict entries from ScaleRuleCache
• Link: [BUG] Scale rule deletion does not evict entries from ScaleRuleCache #6972

Please review when you have time. Thank you! 🙏