wealoha thrift-client-pool 总结

DefaultEvictionPolicy类是EvictionPolicy接口的实现主要描述，pool中那些idel对象会被Evict，回收。
关键代码如下：

public boolean evict(EvictionConfig config, PooledObject<T> underTest,
            int idleCount) {

        if ((config.getIdleSoftEvictTime() < underTest.getIdleTimeMillis() &&
                config.getMinIdle() < idleCount) ||
                config.getIdleEvictTime() < underTest.getIdleTimeMillis()) {
            return true;
        }
        return false;
    }

ObjectPool 接口：

Object obj = null
try{
　　obj = pool.borrowObject();
　　try{
　　　　//...use the object...
　　　　}catch(Exception e) {
　　　　　　pool.invalidateObject(obj);// invalidate the object
　　　　　　// do not return the object to the pool twice
　　　　　　obj = null
　　　　}finally{
　　　　　　// make sure the object is returned to the pool
　　　　　　if(null!= obj) pool.returnObject(obj);

　　　　} 
}catch(Exception e) { // failed to borrow an object }

PooledObjectState 定义池对象的所有可能状态：

public enum PooledObjectState {
    /**
     * In the queue, not in use.
     */
    IDLE,

    /**
     * In use.
     */
    ALLOCATED,

    /**
     * In the queue, currently being tested for possible eviction.
     */
    EVICTION,

    /**
     * Not in the queue, currently being tested for possible eviction. An
     * attempt to borrow the object was made while being tested which removed it
     * from the queue. It should be returned to the head of the queue once
     * eviction testing completes.
     * TODO: Consider allocating object and ignoring the result of the eviction
     *       test.
     */
    EVICTION_RETURN_TO_HEAD,

    /**
     * In the queue, currently being validated.
     */
    VALIDATION,

    /**
     * Not in queue, currently being validated. The object was borrowed while
     * being validated and since testOnBorrow was configured, it was removed
     * from the queue and pre-allocated. It should be allocated once validation
     * completes.
     */
    VALIDATION_PREALLOCATED,

    /**
     * Not in queue, currently being validated. An attempt to borrow the object
     * was made while previously being tested for eviction which removed it from
     * the queue. It should be returned to the head of the queue once validation
     * completes.
     */
    VALIDATION_RETURN_TO_HEAD,

    /**
     * Failed maintenance (e.g. eviction test or validation) and will be / has
     * been destroyed
     */
    INVALID,

    /**
     * Deemed abandoned, to be invalidated.
     */
    ABANDONED,

    /**
     * Returning to the pool.
     */
    RETURNING
}

ThriftClientPool 类剖析：

• 设置配置
  • TestOnReturn= true
  • TestOnBorrow=true
• GenericObjectPool对象池构建：关键代码如下：

• new GenericObjectPool<>(new BasePooledObjectFactory<ThriftClient<T>>() {
  
              @Override
              public ThriftClient<T> create() throws Exception {
  
                  // get from global list first
                  List<ServiceInfo> serviceList = ThriftClientPool.this.services;
                  ServiceInfo serviceInfo = getRandomService(serviceList);
                  TTransport transport = getTransport(serviceInfo);
  
                  try {
                      transport.open();
                  } catch (TTransportException e) {
                      logger.info("transport open fail service: host={}, port={}",
                              serviceInfo.getHost(), serviceInfo.getPort());
                      if (poolConfig.isFailover()) {
                          while (true) {
                              try {
                                  // mark current fail and try next, until none service available
                                  serviceList = removeFailService(serviceList, serviceInfo);
                                  serviceInfo = getRandomService(serviceList);
                                  transport = getTransport(serviceInfo); // while break here
                                  logger.info("failover to next service host={}, port={}",
                                          serviceInfo.getHost(), serviceInfo.getPort());
                                  transport.open();
                                  break;
                              } catch (TTransportException e2) {
                                  logger.warn("failover fail, services left: {}", serviceList.size());
                              }
                          }
                      } else {
                          throw new ConnectionFailException("host=" + serviceInfo.getHost() + ", ip="
                                  + serviceInfo.getPort(), e);
                      }
                  }
  
                  ThriftClient<T> client = new ThriftClient<>(clientFactory.createClient(transport),
                          pool, serviceInfo);
  
                  logger.debug("create new object for pool {}", client);
                  return client;
              }
  
              @Override
              public PooledObject<ThriftClient<T>> wrap(ThriftClient<T> obj) {
                  return new DefaultPooledObject<>(obj);
              }
  
              @Override
              public boolean validateObject(PooledObject<ThriftClient<T>> p) {
                  ThriftClient<T> client = p.getObject();
  
                  // check if return client in current service list if 
                  if (serviceReset) {
                      if (!ThriftClientPool.this.services.contains(client.getServiceInfo())) {
                          logger.warn("not return object cuase it's from previous config {}", client);
                          client.closeClient();
                          return false;
                      }
                  }
  
                  return super.validateObject(p);
              }
  
              @Override
              public void destroyObject(PooledObject<ThriftClient<T>> p) throws Exception {
                  p.getObject().closeClient();
                  super.destroyObject(p);
              }
          }

   X iface 返回TServiceClient的代理对象关键代码如下：可以看到首先从池中借对象，然后生成TServiceClient的代理对象，代理handler主要实际执行thrift方法，成功时归还到池，失败时需要关闭TServiceClient，并在池中invalidateObject(ThriftClient)

UML类关系图：