Springboot Actuator的组件编写

ゝ一纸荒年。 2022-01-30 06:19 208阅读 0赞

# Springboot Actuator的组件编写 #

### 前置说明 ###

因为之前编写了redis-starter以及cache-starter, 然后最近有学习了springboot的actuator相关的知识,了解到springboot自己的**spring-boot-starter-data-redis**是有redis的健康状态监测的,然后**spring-boot-starter-cache**也有关于缓存命中的相关信息暴露,所以也想到了自己写的starter也加上相关的信息暴露并整合到springboot的actuator中进行暴露.

### 相关概念了解 ###

*  RedisHealthIndicator  
    这个就是**spring-boot-starter-data-redis**提供的关于redis健康检测信息提供类,待会儿我也会模仿写一个.
 *  CacheStatisticsProvider,CacheStatistics  
    这两个就是**spring-boot-starter-cache**提供的,一个是缓存信息的提供类,一个是spring提供的缓存统计持有类.

### CustomRedisHealthIndicator编写 ###

首先 可以参考以下spring自身对redis健康检测的实现RedisHealthIndicator

...
    @Override
    	protected void doHealthCheck(Health.Builder builder) throws Exception {
    		RedisConnection connection = RedisConnectionUtils
    				.getConnection(this.redisConnectionFactory);
    		try {
    			if (connection instanceof RedisClusterConnection) {
    				ClusterInfo clusterInfo = ((RedisClusterConnection) connection)
    						.clusterGetClusterInfo();
    				builder.up().withDetail("cluster_size", clusterInfo.getClusterSize())
    						.withDetail("slots_up", clusterInfo.getSlotsOk())
    						.withDetail("slots_fail", clusterInfo.getSlotsFail());
    			}
    			else {
    				Properties info = connection.info();
    				builder.up().withDetail(VERSION, info.getProperty(REDIS_VERSION));
    			}
    		}
    		finally {
    			RedisConnectionUtils.releaseConnection(connection,
    					this.redisConnectionFactory);
    		}
    	}
    	...

可以看出其实主要是调用info接口来获取redis的信息,然后继续暴露.

我们继续模仿,如下面的代码所示

public class CustomRedisHealthIndicator extends AbstractHealthIndicator {
        @Autowired
        RedisUtil redisUtil;
        
        @Override
        protected void doHealthCheck(Health.Builder builder) throws Exception {
            try (Jedis jedis = redisUtil.getJedis()){
                String info = jedis.info();
                builder.up().withDetail("info", info);
            }
        }
    }

这里简单的把info直接返回即可,然后将其进行自动装配,我们可以将自动装配的时间放到springboot的HealthIndicatorAutoConfiguration自动装配之前,这样可以确保我们的Indicator能被聚合进去,进行统一的展示, 代码如下

@AutoConfigureBefore(HealthIndicatorAutoConfiguration. class)
    @Configuration
    @ConditionalOnProperty(value = "redis.health", havingValue = "true")
    public class CustomRedisHealthConfiguration {
    
        @Bean
        public CustomRedisHealthIndicator customRedisHealthIndicator(){
            return new CustomRedisHealthIndicator();
        }
    
    }

### CustomCachePublicMetrics编写 ###

照理,还是先参考spring 的实现CachePublicMetrics

...
    @Override
    	public Collection<Metric<?>> metrics() {
    		Collection<Metric<?>> metrics = new HashSet<Metric<?>>();
    		for (Map.Entry<String, List<CacheManagerBean>> entry : getCacheManagerBeans()
    				.entrySet()) {
    				//添加信息
    			addMetrics(metrics, entry.getKey(), entry.getValue()); 
    		}
    		return metrics;
    	}
    
    ...
    	private void addMetrics(Collection<Metric<?>> metrics, String cacheName,
    			List<CacheManagerBean> cacheManagerBeans) {
    		for (CacheManagerBean cacheManagerBean : cacheManagerBeans) {
    			CacheManager cacheManager = cacheManagerBean.getCacheManager();
    			Cache cache = unwrapIfNecessary(cacheManager.getCache(cacheName));
    			//获取信息
    			CacheStatistics statistics = getCacheStatistics(cache, cacheManager);
    			if (statistics != null) {
    				String prefix = cacheName;
    				if (cacheManagerBeans.size() > 1) {
    					prefix = cacheManagerBean.getBeanName() + "_" + prefix;
    				}
    				prefix = "cache." + prefix + (prefix.endsWith(".") ? "" : ".");
    				metrics.addAll(statistics.toMetrics(prefix));
    			}
    		}
    	}
    	...
    	@SuppressWarnings({ "rawtypes", "unchecked" })
    	private CacheStatistics getCacheStatistics(Cache cache, CacheManager cacheManager) {
    		if (this.statisticsProviders != null) {
    			for (CacheStatisticsProvider provider : this.statisticsProviders) {
    				Class<?> cacheType = ResolvableType
    						.forClass(CacheStatisticsProvider.class, provider.getClass())
    						.resolveGeneric();
    				if (cacheType.isInstance(cache)) {
    				   //获取信息
    					CacheStatistics statistics = provider.getCacheStatistics(cacheManager,   
    							cache);
    					if (statistics != null) {
    						return statistics;
    					}
    				}
    			}
    		}
    		return null;
    	}
    	...

可以看到信息主要是从provider获取,随便看一个ConcurrentMapCacheStatisticsProvider

public class ConcurrentMapCacheStatisticsProvider
    		implements CacheStatisticsProvider<ConcurrentMapCache> {
    
    	@Override
    	public CacheStatistics getCacheStatistics(CacheManager cacheManager,
    			ConcurrentMapCache cache) {
    		DefaultCacheStatistics statistics = new DefaultCacheStatistics();
    		statistics.setSize((long) cache.getNativeCache().size());
    		return statistics;
    	}
    
    }

因为我们实现的cache并没有用到spring的接口cacheManage和cache,所以就大概实现类似的功能如下

@AllArgsConstructor
    public class CustomCacheStatistucsProvider {
        
        private CacheUtil cacheUtil;
        private CacheSupport cacheSupport;
        private CacheProperties cacheProperties;
        
        
        public CacheStatistics getCacheStatistics() {
            DefaultCacheStatistics statistics = new DefaultCacheStatistics();
            statistics.setSize((long) cacheUtil.size(cacheProperties.getPrefix() + "*")); //缓存个数
            double hitRatio = cacheSupport.getSuccess().doubleValue() / cacheSupport.getTotal().doubleValue(); 
            statistics.setHitRatio(hitRatio); //命中概率
            statistics.setMissRatio(1 - hitRatio); //未命中概率
            return statistics;
        }
        
    }

然后创建一个暴露类

public class CustomCachePublicMetrics implements PublicMetrics {
        
        CustomCacheStatistucsProvider customCacheStatistucsProvider;
        
        
        @Override
        public Collection<Metric<?>> metrics() {
            CacheStatistics cacheStatistics = customCacheStatistucsProvider.getCacheStatistics();
            Collection<Metric<?>> metrics = cacheStatistics.toMetrics("cache.");
            return metrics;
        }
    }

然后编写自动配置类,按照惯例其配置顺序在PublicMetricsAutoConfiguration之前

@AutoConfigureBefore(PublicMetricsAutoConfiguration.class)
    @Configuration
    @ConditionalOnProperty("cache.metric")
    public class CustomCachePublicMetricsConfiguration {
        
        @Bean
        public CustomCacheStatistucsProvider customCacheStatistucsProvider(){
            return new CustomCacheStatistucsProvider();
        }
        
        @Bean
        public CustomCachePublicMetrics customCachePublicMetrics(){
            return new CustomCachePublicMetrics();
        }
    
    }

这样我们的代码就基本编写完毕了.别忘了在spring.factories加上相关的配置类.

### 查看结果 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkeTE5OTY_size_16_color_FFFFFF_t_70]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkeTE5OTY_size_16_color_FFFFFF_t_70 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkeTE5OTY_size_16_color_FFFFFF_t_70]: /images/20220130/1924bb2a1f8940458110081a0b3448ab.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkeTE5OTY_size_16_color_FFFFFF_t_70 1]: /images/20220130/766b13a2f16248938956a6ca878d599c.png