Ribbon配置自定义负载均衡策略

曾经终败给现在 2022-12-21 03:15 211阅读 0赞

本篇接于上篇[《Ribbon配置负载均衡策略》][Ribbon]。  
我们来自定义一个基于一致性哈希规则的负载均衡策略。  
Deme项目结构如下：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x0MzI2MDMwNDM0_size_16_color_FFFFFF_t_70_pic_center]

*  MyRule

@NoArgsConstructor
    public class MyRule extends AbstractLoadBalancerRule implements IRule { 
    
    
        @Override
        public void initWithNiwsConfig(IClientConfig iClientConfig) { 
    
        }
    
        @Override
        public Server choose(Object key) { 
            HttpServletRequest request = ((ServletRequestAttributes)
                    RequestContextHolder.getRequestAttributes())
                    .getRequest();
    		// 在这里，我们简单的以uri作为哈希的key
            String uri = request.getServletPath() + "?" + request.getQueryString();
            return route(uri.hashCode(), getLoadBalancer().getAllServers());
        }
    
        public Server route(int hashId, List<Server> addressList) { 
            if (CollectionUtils.isEmpty(addressList)) { 
                return null;
            }
    
            TreeMap<Long, Server> address = new TreeMap<>();
            addressList.stream().forEach(e -> { 
                // 虚化若干个服务节点，到环上
                for (int i = 0; i < 8; i++) { 
                    long hash = hash(e.getId() + i);
                    address.put(hash, e);
                }
            });
    
            long hash = hash(String.valueOf(hashId));
            SortedMap<Long, Server> last = address.tailMap(hash);
            // 当request URL的hash值大于任意一个服务器对应的hashKey，
            // 取address中的第一个节点
            if (last.isEmpty()) { 
                address.firstEntry().getValue();
            }
    
            return last.get(last.firstKey());
        }
    
        public long hash(String key) { 
            MessageDigest md5;
            try { 
                md5 = MessageDigest.getInstance("MD5");
            } catch (NoSuchAlgorithmException e) { 
                throw new RuntimeException(e);
            }
    
            byte[] keyByte = null;
            try { 
                keyByte = key.getBytes("UTF-8");
            } catch (UnsupportedEncodingException e) { 
                throw new RuntimeException(e);
            }
    
            md5.update(keyByte);
            byte[] digest = md5.digest();
    
            long hashCode = ((long) (digest[2] & 0xFF << 16))
                    | ((long) (digest[1] & 0xFF << 8))
                    | ((long) (digest[0] & 0xFF));
    
            return hashCode & 0xffffffffL;
        }
    
    }

*  修改RibbonConnfiguration中的`@RibbonClient`注解

@Configuration
    @RibbonClient(name = "eureka-client", configuration = MyRule.class)
    public class RibbonConfiguration { 
    
    }

到这里，自定义Ribbon负载均衡策略就完成了！

[Ribbon]: https://jiandansuifeng.blog.csdn.net/article/details/109678000
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x0MzI2MDMwNDM0_size_16_color_FFFFFF_t_70_pic_center]: /images/20221120/b6a0448185f748c99afb8d3dc7c8400f.png