JedisCluster性能指标的收集——Prometheus
所有的性能收集其实都是基于aop的，对于jedisCluster性能（jedis的一样）的收集，因为其并没有提供类似于mybatis的intercept机制，所以只能手动实现可供收集性能数据的切面。
说到切面，第一个就会想到代理，接下来就通过cglib实现对jedisCluster的代理。
动态代理的生成工厂SPI扩展：JedisClusterProxyFactory
@Spi public interface JedisClusterProxyFactory { <T> T getProxy(Class<T> clz, String namespace, Class[] argumentTypes, Object[] arguments); }
扩展实现：JedisClusterCglibProxyFactory
这里说一下cglib，其中的Enhancer在spring aop里使用很多，它相比于JDK的动态代理Proxy，可以为无接口的类创建代理。它会根据某个给定的类创建子类，并且所有非final的方法都带有回调钩子方法。
@SpiMeta(name = "cglib") public class JedisClusterCglibProxyFactory implements JedisClusterProxyFactory { @Override @SuppressWarnings("unchecked") public <T> T getProxy(Class<T> clz, String namespace, Class[] argumentTypes, Object[] arguments) { //创建一个字节码增强器，用来创建代理类 Enhancer enhancer = new Enhancer(); //设置父类，即要被代理的Class对象 enhancer.setSuperclass(clz); //设置回调的狗子方法 enhancer.setCallback(new JedisClusterMethodInterceptor(namespace)); return (T) enhancer.create(argumentTypes, arguments); } }
其中的JedisClusterMethodInterceptor继承自cglib的方法拦截器MethodInterceptor的实现：从下面代码可以看出指标收集就是在拦截器中进行的。
public class JedisClusterMethodInterceptor extends BaseMethodInterceptor { public JedisClusterMethodInterceptor(String namespace) { this.namespace = namespace; } @Override protected Object innerInvoke(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { return proxy.invokeSuper(obj, args); } @Override protected String getType() { return "jedisCluster"; } }
public abstract class BaseMethodInterceptor implements MethodInterceptor { private static Map<String, Stats> statsMap = new ConcurrentHashMap<>(); String namespace; @Override public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { //将请求的方法（如get/incr等），namespace标识使用caf框架中使用@EnableJedisClusterClient定义的namespace，如shua-kxct final String[] tags = {"method", method.getName(), "namespace", namespace}; long begin = System.currentTimeMillis(); Object result; //获取指标收集器 Stats stats = getOrInitStats(); //对每次redis请求gauge+1 stats.incConc(tags); try { //通过代理调用jedisCluster具体的方法 result = innerInvoke(obj, method, args, proxy); } catch (Throwable t) { //统计错误数 stats.error(tags); throw t; } finally { //统计本次请求的执行时间 stats.observe(System.currentTimeMillis() - begin, tags); //请求结束gauge-1 stats.decConc(tags); } return result; } protected abstract Object innerInvoke(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable; protected abstract String getType(); private Stats getOrInitStats() { String statsKey = getType() + "::" + namespace; Stats stats = statsMap.get(statsKey); if (stats != null) { return stats; } stats = Profiler.Builder.builder().type(getType()).namespace(namespace).build(); statsMap.putIfAbsent(statsKey, stats); return statsMap.get(statsKey); } }
这里有一个注意的地方，调用具体的jedisCluster方法是通过innerInvoke——>proxy.invokeSuper(obj, args)这种方式调用的，而不是像JDK的InvocationHandler通过method去调用具体方法，因为使用method调用会再次进入拦截器，所以只能通过第四个参数proxy调用。
动态代理生成工厂类：PjedisClusterFactory，用于生成jedisCluster代理对象。
public class PjedisClusterFactory { private static String fixNamespace() { String namespace = "default"; if (StringUtils.isNotEmpty(JedisPropsHolder.NAMESPACE.get())) { namespace = JedisPropsHolder.NAMESPACE.get(); } return namespace; } private static JedisCluster newJedisCluster(Class[] classes, Object[] objects) { //获取生成的代理对象 final JedisCluster jedisCluster = ExtensionLoader.getExtensionLoader(JedisClusterProxyFactory.class) .getExtension("cglib") .getProxy(JedisCluster.class, fixNamespace(), classes, objects); //将代理对象注册到健康监测调度器，原理和之前介绍的Druid一样 JedisClusterHealthTracker.addJedisCluster(fixNamespace(), jedisCluster); return jedisCluster; } private static Class[] CONST_1 = new Class[]{HostAndPort.class}; public static JedisCluster newJedisCluster(HostAndPort node) { return newJedisCluster(CONST_1, new Object[]{node}); } private static Class[] CONST_2 = new Class[]{HostAndPort.class, int.class}; public static JedisCluster newJedisCluster(HostAndPort node, int timeout) { return newJedisCluster(CONST_2, new Object[]{node, timeout}); } private static Class[] CONST_3 = new Class[]{HostAndPort.class, int.class, int.class}; public static JedisCluster newJedisCluster(HostAndPort node, int timeout, int maxAttempts) { return newJedisCluster(CONST_3, new Object[]{node, timeout, maxAttempts}); } private static Class[] CONST_4 = new Class[]{HostAndPort.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(HostAndPort node, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_4, new Object[]{node, poolConfig}); } private static Class[] CONST_5 = new Class[]{HostAndPort.class, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(HostAndPort node, int timeout, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_5, new Object[]{node, timeout, poolConfig}); } private static Class[] CONST_6 = new Class[]{HostAndPort.class, int.class, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(HostAndPort node, int timeout, int maxAttempts, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_6, new Object[]{node, timeout, maxAttempts, poolConfig}); } private static Class[] CONST_7 = new Class[]{HostAndPort.class, int.class, int.class, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(HostAndPort node, int connectionTimeout, int soTimeout, int maxAttempts, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_7, new Object[]{node, connectionTimeout, soTimeout, maxAttempts, poolConfig}); } private static Class[] CONST_8 = new Class[]{HostAndPort.class, int.class, int.class, int.class, String.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(HostAndPort node, int connectionTimeout, int soTimeout, int maxAttempts, String password, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_8, new Object[]{node, connectionTimeout, soTimeout, maxAttempts, password, poolConfig}); } private static Class aClass = new TypeToken<Set<HostAndPort>>() {}.getRawType(); private static Class[] CONST_9 = new Class[]{aClass}; public static JedisCluster newJedisCluster(Set<HostAndPort> nodes) { return newJedisCluster(CONST_9, new Object[]{nodes}); } private static Class[] CONST_10 = new Class[]{aClass, int.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> nodes, int timeout) { return newJedisCluster(CONST_10, new Object[]{nodes, timeout}); } private static Class[] CONST_11 = new Class[]{aClass, int.class, int.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> nodes, int timeout, int maxAttempts) { return newJedisCluster(CONST_11, new Object[]{nodes, timeout, maxAttempts}); } private static Class[] CONST_12 = new Class[]{aClass, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> nodes, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_12, new Object[]{nodes, poolConfig}); } private static Class[] CONST_13 = new Class[]{aClass, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> nodes, int timeout, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_13, new Object[]{nodes, timeout, poolConfig}); } private static Class[] CONST_14 = new Class[]{aClass, int.class, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> jedisClusterNode, int timeout, int maxAttempts, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_14, new Object[]{jedisClusterNode, timeout, maxAttempts, poolConfig}); } private static Class[] CONST_15 = new Class[]{aClass, int.class, int.class, int.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> jedisClusterNode, int connectionTimeout, int soTimeout, int maxAttempts, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_15, new Object[]{jedisClusterNode, connectionTimeout, soTimeout, maxAttempts, poolConfig}); } private static Class[] CONST_16 = new Class[]{aClass, int.class, int.class, int.class, String.class, GenericObjectPoolConfig.class}; public static JedisCluster newJedisCluster(Set<HostAndPort> jedisClusterNode, int connectionTimeout, int soTimeout, int maxAttempts, String password, final GenericObjectPoolConfig poolConfig) { return newJedisCluster(CONST_16, new Object[]{jedisClusterNode, connectionTimeout, soTimeout, maxAttempts, password, poolConfig}); } }
介绍完如何创建代理对象，然后在代理对象的钩子回调方法拦截器中收集指标，接下来看一下在项目中的实际应用。
封装的JedisClusterClient：其持有的JedisCluster实际是通过cglib生成的代理对象。
public JedisClusterClient(String namespace, JedisPoolConfig jedisPoolConfig, String address) throws NoSuchFieldException { this.namespace = namespace; this.address = address; this.jedisPoolConfig = jedisPoolConfig; String[] commonClusterRedisArray = address.split(","); Set<HostAndPort> jedisClusterNodes = new HashSet<>(); for (String clusterHostAndPort : commonClusterRedisArray) { String host = clusterHostAndPort.split(":")[0].trim(); int port = Integer.parseInt(clusterHostAndPort.split(":")[1].trim()); jedisClusterNodes.add(new HostAndPort(host, port)); } JedisPropsHolder.NAMESPACE.set(namespace); this.jedisCluster = PjedisClusterFactory.newJedisCluster(jedisClusterNodes, defaultConnectTimeout, defaultConnectMaxAttempts, jedisPoolConfig); Field field = BinaryJedisCluster.class.getDeclaredField("connectionHandler"); field.setAccessible(true); connectionHandler = (JedisSlotBasedConnectionHandler) ReflectionUtils.getField(field, this.jedisCluster); Field cacheFiled = JedisClusterConnectionHandler.class.getDeclaredField("cache"); cacheFiled.setAccessible(true); JedisClusterInfoCache cache = (JedisClusterInfoCache) ReflectionUtils.getField(cacheFiled, connectionHandler); assert cache != null; nodes = cache.getNodes(); }
最后是指标收集结果：
