rocksdb/thrift/lib/cpp/transport/TSocketPool.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#ifndef THRIFT_TRANSPORT_TSOCKETPOOL_H_
#define THRIFT_TRANSPORT_TSOCKETPOOL_H_ 1

#include <vector>
#include <limits.h>
#include "thrift/lib/cpp/transport/TSocket.h"

namespace apache { namespace thrift { namespace transport {

 /**
  * Class to hold server information for TSocketPool
  *
  */
class TSocketPoolServer {

  public:
  /**
   * Default constructor for server info
   */
  TSocketPoolServer();

  /**
   * Constructor for TSocketPool server
   */
  TSocketPoolServer(const std::string &host, int port);

  // Host name
  std::string host_;

  // Port to connect on
  int port_;

  // Socket for the server
  int socket_;

  // Last time connecting to this server failed
  int lastFailTime_;

  // Number of consecutive times connecting to this server failed
  int consecutiveFailures_;
};

/**
 * TCP Socket implementation of the TTransport interface.
 *
 */
class TSocketPool : public TSocket {

 public:

   /**
    * Socket pool constructor
    */
   TSocketPool();

   /**
    * Socket pool constructor
    *
    * @param hosts list of host names
    * @param ports list of port names
    */
   TSocketPool(const std::vector<std::string> &hosts,
               const std::vector<int> &ports);

   /**
    * Socket pool constructor
    *
    * @param servers list of pairs of host name and port
    */
   /* implicit */
   TSocketPool(const std::vector<std::pair<std::string, int> >& servers);

   /**
    * Socket pool constructor
    *
    * @param servers list of TSocketPoolServers
    */
   /* implicit */
   TSocketPool(const
               std::vector< boost::shared_ptr<TSocketPoolServer> >& servers);

   /**
    * Socket pool constructor
    *
    * @param host single host
    * @param port single port
    */
   TSocketPool(const std::string& host, int port);

   /**
    * Destroys the socket object, closing it if necessary.
    */
   virtual ~TSocketPool();

   /**
    * Add a server to the pool
    */
   void addServer(const std::string& host, int port);

   /**
    * Add a server to the pool
    */
  void addServer(boost::shared_ptr<TSocketPoolServer> &server);

   /**
    * Set list of servers in this pool
    */
  void setServers(const std::vector< boost::shared_ptr<TSocketPoolServer> >& servers);

   /**
    * Get list of servers in this pool
    */
  void getServers(std::vector< boost::shared_ptr<TSocketPoolServer> >& servers);

   /**
    * Get port of the current server
    */
  int getCurrentServerPort();

   /**
    * Get host of the current server
    */
  std::string getCurrentServerHost();

   /**
    * Sets how many times to keep retrying a host in the connect function.
    */
   void setNumRetries(int numRetries);

   /**
    * Sets how long to wait until retrying a host if it was marked down
    */
   void setRetryInterval(int retryInterval);

   /**
    * Sets how many times to keep retrying a host before marking it as down.
    */
   void setMaxConsecutiveFailures(int maxConsecutiveFailures);

   /**
    * Turns randomization in connect order on or off.
    */
   void setRandomize(bool randomize);

   /**
    * Whether to always try the last server.
    */
   void setAlwaysTryLast(bool alwaysTryLast);

   /**
    * Sets the max number of servers to try in open
    */
   void setMaxServersToTry(unsigned int maxServersToTry);

   /**
    * Creates and opens the UNIX socket.
    */
   void open();

   /*
    * Closes the UNIX socket
    */
   void close();

 protected:

  void setCurrentServer(const boost::shared_ptr<TSocketPoolServer> &server);

   /** List of servers to connect to */
  std::vector< boost::shared_ptr<TSocketPoolServer> > servers_;

  /** Current server */
  boost::shared_ptr<TSocketPoolServer> currentServer_;

   /** How many times to retry each host in connect */
   int numRetries_;

   /** Retry interval in seconds, how long to not try a host if it has been
    * marked as down.
    */
   int retryInterval_;

   /** Max consecutive failures before marking a host down. */
   int maxConsecutiveFailures_;

   /** Try hosts in order? or Randomized? */
   bool randomize_;

   /** Always try last host, even if marked down? */
   bool alwaysTryLast_;

   /** Number of servers to try in open(), default is UINT_MAX */
   unsigned int maxServersToTry_;
};

}}} // apache::thrift::transport

#endif // #ifndef _THRIFT_TRANSPORT_TSOCKETPOOL_H_