acl/lib_acl_cpp/include/acl_cpp/redis/redis_cluster.hpp

#pragma once
#include "acl_cpp/acl_cpp_define.hpp"
#include <vector>
#include "acl_cpp/stdlib/string.hpp"
#include "acl_cpp/connpool/connect_manager.hpp"

namespace acl
{

class redis_pool;

/**
 * redis 客户端集群类，通过将此类对象注册入 redis 客户端命令类(redis_command)，
 * 则使所有的客户端命令自动支持集群版 redis 命令。
 * redis client cluster class. The class's object is set in the redis_command
 * using redis_command::set_cluster(redis_cluster*), and all the redis client
 * command will support the redis cluster mode.
 */
class ACL_CPP_API redis_cluster : public connect_manager
{
public:
	/**
	 * 构造函数;
	 * constructor
	 * @param conn_timeout {int} 服务器连接超时时间(秒);
	 *  timeout in seconds for connecting the redis-server
	 * @param rw_timeout {int}　网络 IO 读写超时时间(秒);
	 *  read/write timeout in seconds from/to the redis-server
	 * @param max_slot {int} 哈希槽最大值; the max hash-slot value of keys
	 */
	redis_cluster(int conn_timeout, int rw_timeout, int max_slot = 16384);
	virtual ~redis_cluster();

	/**
	 * 根据哈希槽值获得对应的连接池;
	 * get one connection pool with the given slot
	 * @param slot {int} 哈希槽值;
	 *  the hash-slot value of key
	 * @return {redis_pool*} 如果对应的哈希槽不存在则返回 NULL;
	 *  return the connection pool of the hash-slot, and return NULL
	 *  when the slot not exists
	 */
	redis_pool* peek_slot(int slot);

	/**
	 * 动态设置哈希槽值对应的 redis 服务地址，该函数被调用时内部有线程锁保护;
	 * dynamicly set redis-server addr with one slot, which is protected
	 * by thread mutex internal, no one will be set if the slot were
	 * beyyond the max hash-slot
	 * @param slot {int} 哈希槽值;
	 *  the hash-slot
	 * @param addr {const char*} redis 服务器地址;
	 *  one redis-server addr
	 */
	void set_slot(int slot, const char* addr);

	/**
	 * 动态清除哈希槽对应的 redis 服务地址，以便于重新计算位置，内部有线程锁保护机制;
	 * dynamicly remove one slot and redis-server addr mapping, which is
	 * protected by thread mutex
	 * @param slot {int} 哈希槽值;
	 *  hash-slot value
	 */
	void clear_slot(int slot);

	/**
	 * 获得哈希槽最大值;
	 * get the max hash-slot
	 * @return {int}
	 */
	int get_max_slot() const
	{
		return max_slot_;
	}

	//////////////////////////////////////////////////////////////////////
	/**
	 * 设置协议重定向次数的阀值，默认值为 15;
	 * set redirect limit for MOVE/ASK, default is 15
	 * @param max {int} 重定向次数阀值，只有当该值 > 0 时才有效;
	 *  the redirect times limit for MOVE/ASK commands
	 */
	void set_redirect_max(int max);

	/**
	 * 设置协议重定向次数的阀值;
	 * get redirect limit of MOVE/ASK commands in one redis redirect process
	 * @return {int}
	 */
	int get_redirect_max() const
	{
		return redirect_max_;
	}

	/**
	 * 当重定向次数 >= 2 时允许休眠的时间(毫秒)，默认值为 100 毫秒，这样做的
	 * 好处是当一个 redis 服务主结点掉线后，其它从结点升级为主结点是需要
	 * 时间的(由 redis.conf 中的 cluster-node-timeout 配置项决定)，所以
	 * 为了在重定向的次数范围内不报错需要等待从结点升级为主结点;
	 * if redirect happenning more than 2 in one redis command process,
	 * the process can sleep for a one avoiding redirect too fast, you
	 * can set the waiting time with microsecond here, default value is
	 * 100 microseconds; this only happends when redis-server died.
	 * @param n {int} 每次重定向时的休息时间(毫秒)，默认值为 100 毫秒;
	 * microseonds to sleep when redirect times are more than 2,
	 * default is 100 ms
	 */
	void set_redirect_sleep(int n);

	/**
	 * 获得 set_redirect_sleep 设置的或默认的时间;
	 * get sleep time set by set_redirect_sleep function
	 * @return {int} 单位为毫秒;
	 *  return sleep value in microsecond
	 */
	int get_redirect_sleep() const
	{
		return redirect_sleep_;
	}

protected:
	/**
	 * 基类纯虚函数，用来创建连接池对象;
	 * virtual function of base class, which is used to create
	 * the connection pool
	 * @param addr {const char*} 服务器监听地址，格式：ip:port;
	 * the server addr for the connection pool, such as ip:port
	 * @param count {int} 连接池的大小限制;
	 * the max connections in one connection pool
	 * @param idx {size_t} 该连接池对象在集合中的下标位置(从 0 开始);
	 * the index of the connection pool in pool array
	 */
	virtual connect_pool* create_pool(const char* addr,
		int count, size_t idx);
private:
	int   conn_timeout_;
	int   rw_timeout_;
	int   max_slot_;
	const char**  slot_addrs_;
	std::vector<char*> addrs_;
	int   redirect_max_;
	int   redirect_sleep_;
};

} // namespace acl