memcached 集群c++客户端
memcached 是一个高性能内存缓存,在作为缓存,不需要持久化的场性能稳定,由于现在服务器内存较大,很多应用场景单台memcached就能满足业务需求,普通的官方c API
就能满足需求。
而大型的应用数据量很大,也应该考虑单点故障,集群化可以分散压力,单点故障影响较小。集群的管理通常有两种方式:1.普通hash 2.一致性hash
1.普通hash实现相对简单,效率更高,但是不能动态扩展,这种能满足业务数据不是经常扩展比较固定的场景,单点故障影响不大,这种长期其实很多。通常的mysql + memcached 架构很适合这种方式
2.一致性哈希的优点就是可以动态扩展,适合业务数据持续增长的场景,实现相对复杂,通常需要代理服务器管理
下面是自己实现的基于hash的memcached 集群c++客户端代码,经过线上测试,性能和稳定性没有太大的问题。
/************************************************ function: c++ mcached api author:liuyi date:2012.12.31 version:3.0 modify:2014.10.15 *************************************************/ #ifndef MULI_MEMCACHE_H #define MULI_MEMCACHE_H #include <iostream> #include <string> #include <vector> #include <map> #include <time.h> #include "libmemcached/memcached.h" using namespace std; typedef unsigned int(*hash_fun)(const char*); unsigned int rs_hash(const char *str) { unsigned int b = 378551; unsigned int a = 63689; unsigned int hash = 0; while (*str) { hash = hash * a + (*str++); a *= b; } return (hash & 0x7FFFFFFF); } struct memcache_info { string host; int port; }; class single_memcached { public: single_memcached() { servers = NULL; memc = NULL; rc = MEMCACHED_SUCCESS; result_buff = NULL; } virtual ~single_memcached() { memcached_free(memc); delete []result_buff; } enum {MAX_VALUE_LEN = 1024*1024}; bool init(const char*host, const int& port) { result_buff = new char[MAX_VALUE_LEN]; if(result_buff == NULL) return false; memc = memcached_create(NULL); servers = memcached_server_list_append(NULL, host, port, &rc); if(servers == NULL) return false; rc = memcached_server_push(memc, servers); if(rc == MEMCACHED_SUCCESS) { memcached_server_free(servers); return true; } else { return false; } } //插入或者覆盖原有数据 expiration为有效时间,默认0为一直有效 bool set(const char* key, const char* value, time_t expiration = 0) { rc = memcached_set(memc, key, strlen(key), value, strlen(value), expiration, 0); return rc == MEMCACHED_SUCCESS; } //删除数据 expiration为有效时间,默认0为立即生效 bool delete_k_v(const char* key, time_t expiration = 0) { rc = memcached_delete(memc, key, strlen(key), expiration); return rc == MEMCACHED_SUCCESS; } char *get(const char* key) { size_t value_len = 0; uint32_t flag = 0; char *ret = memcached_get(memc, key, strlen(key), &value_len, &flag, &rc); if(ret == NULL) { return NULL; } memset(result_buff, 0, MAX_VALUE_LEN); if(value_len < MAX_VALUE_LEN) { memcpy(result_buff, ret, value_len); free(ret); } return rc == MEMCACHED_SUCCESS && value_len < MAX_VALUE_LEN ? result_buff : NULL; } private: memcached_server_st *servers; memcached_st *memc; memcached_return rc; char *result_buff; }; class mulit_memcached { public: mulit_memcached() { memcache_servers.clear(); memcache_servers_id.clear(); } virtual ~mulit_memcached() { } bool init(const vector<memcache_info>& memcache_info_vec, hash_fun hash = rs_hash) { m_hash_fun = hash; memcache_servers.resize(memcache_info_vec.size()); for(size_t i = 0; i < memcache_info_vec.size(); i++) { char value[1024] = {0}; snprintf(value, 1023, "%s#%d", memcache_info_vec[i].host.c_str(), memcache_info_vec[i].port); memcache_servers_id.insert(pair<unsigned int, string>(i, value)); if(!memcache_servers[i].init(memcache_info_vec[i].host.c_str(), memcache_info_vec[i].port)) { return false; } } return true; } bool set(const char* key, const char* value, time_t expiration = 0) { unsigned int index = m_hash_fun(key) % memcache_servers.size(); return memcache_servers[index].set(key, value, expiration); } bool delete_k_v(const char* key, time_t expiration = 0) { unsigned int index = m_hash_fun(key) % memcache_servers.size(); return memcache_servers[index].delete_k_v(key, expiration); } char *get(const char* key) { unsigned int index = m_hash_fun(key) % memcache_servers.size(); return memcache_servers[index].get(key); } string get_memcache_info(const char* key) { unsigned int index = m_hash_fun(key) % memcache_servers.size(); return memcache_servers_id[index]; } private: vector<single_memcached> memcache_servers; map<unsigned int, string> memcache_servers_id; hash_fun m_hash_fun; }; #endif
#include <iostream> #include <string> #include "memcache_api.h" using namespace std; unsigned int user_define_hash(const char *str) { unsigned int b = 378551; unsigned int a = 63689; unsigned int hash = 0; while (*str) { hash = hash * a + (*str++); a *= b; } hash += 1; hash -= 1; return (hash & 0x7FFFFFFF); } int main(int argc, char *argv[]) { single_memcached mc; if(!mc.init("10.101.88.244", 11212)) { cout<<"mc init error"<<endl; } char key[1024] = {0}; char value[1024] = {"1"}; if(!mc.set(key, value)) { // cout<<"set error"<<endl; } for(int i = 0; i < 1000; i++) { sprintf(key, "%d", i); if(!mc.set(key, key)){cout<<"error"<<endl;} if(mc.get(key))cout<<mc.get(key)<<endl; mc.delete_k_v(key); } memcache_info host_port; host_port.host = "10.101.88.244"; host_port.port = 11211; vector<memcache_info> servers; servers.push_back(host_port); host_port.port = 11212; servers.push_back(host_port); mulit_memcached mulit_memcached_servers; if(!mulit_memcached_servers.init(servers)) //if(!mulit_memcached_servers.init(servers, user_define_hash)) { cout<<"init error"<<endl; } for(int i = 0; i < 1000; i++) { char k[16] = {0}; sprintf(k, "%d", i); //cout<<k<<endl; cout<<mulit_memcached_servers.set(k, k)<<endl;; cout<<mulit_memcached_servers.set(k, k, 100)<<endl;; if(mulit_memcached_servers.get(k))cout<<mulit_memcached_servers.get(k)<<endl; cout<<mulit_memcached_servers.delete_k_v(k)<<endl; cout<<mulit_memcached_servers.get_memcache_info(key)<<endl;//user for log } return 0; }
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。