zehuamama/balancer

🎉 A go library that implements load balancing algorithms. Fast, stable mini layer 7 load balancer.

Stat

Hi there 👋

I'm wanzo, a software engineer at Bytedance. I'm interested in distributed systems and cloud computing.

Tiny Project

• tinyrpc：🚀 Fast, stable, mini RPC framework based on protocol buffer.
• balancer: 🎉 A go library that implements load balancing algorithms. Fast, stable mini layer 7 load balancer.
• redis-tools:⚡A collection of redis tools, including distributed lock, cas, casEx, cad.
• smos: ✨ Serverless multi-objective scheduling algorithm.

balancer's Issues

heartbeat bug

The proxypass does not write the port, causing the heartbeat detection to kick the url out of the balancer

location:                         # route matching for reverse proxy
  - pattern: /
    proxy_pass:                   # URL of the reverse proxy
    - "http://127.0.0.1"
    - "http://127.0.0.1:1013"
    balance_mode: round-robin     # load balancing algorithm

Support IP hash algorithm

添加支持IP哈希算法的balancer : host = CRC32(remoteAddr) % len(hosts)

Support max_allowed configuration

# The maximum number of requests that the balancer can handle at the same time
# 0 refers to no limit to the maximum number of requests
max_allowed: 100

The balance function should use a read-write lock

// Balancer interface is the load balancer for the reverse proxy
type Balancer interface {
	Add(string)
	Remove(string)
	Balance(string) (string, error)
	Inc(string)
	Done(string)
}

// Balance selects a suitable host according
func (r *RoundRobin) Balance(_ string) (string, error) {
	r.Lock()
	defer r.Unlock()
	if len(r.hosts) == 0 {
		return "", NoHostError
	}
	host := r.hosts[r.i%uint64(len(r.hosts))]
	r.i++
	return host, nil
}

Add websocket support

Added TCP load balancing feature

目前Tinybalancer仅支持http、https的代理，考虑是否增加TCP代理的能力

Site unreachable, remove www.taobao.com from load balancer

求助

大佬，我发了一封邮件到你得google邮箱([email protected]),有空麻烦看下呗，这个问题需要解决下，拜托~

Add heartbeat detection

proxy通过试图与passproxy的主机建立TCP的方式进行心跳检测。

func isBackendAlive(u *url.URL) bool {
    timeout := 2 * time.Second
    conn, err := net.DialTimeout("tcp", u.Host, timeout)
    if err != nil {
        log.Println("Site unreachable, error: ", err)
        return false
    }
    _ = conn.Close() // close it, we dont need to maintain this connection
    return true
}

round-robin balancer has a thread-safety problem

Hi~ @zehuamama
I found that round-robin balancer has a thread-safety problem, increasing the current index but the lock is read lock. This may cause the result we get from the round-robin balancer may not be what we want.

Reference: https://github.com/zehuamama/balancer/blob/6e8ef295bbbc76b6815d9f297b26352aeaf37fd4/balancer/round_robin.go#L35C5-L35C5

add new load balancing algorithms

添加基于斐波那契堆的最小负载算法和有界负载一致性哈希算法

Problems when tinybalancer is used nested

// Balancer interface is the load balancer for the reverse proxy
type Balancer interface {
	Add(string)
	Remove(string)
	Balance(string) (string, error)
	Inc(string)
	Done(string)
}

当tinybalancer嵌套使用时，Balance的Key值有可能被网关所代替，考虑是否可以使用X-Real-IP

// ServeHTTP implements a proxy to the http server
func (h *HTTPProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	host, err := h.lb.Balance(util.GetIP(r.RemoteAddr))
	if err != nil {
		w.WriteHeader(http.StatusBadGateway)
		errMsg := fmt.Sprintf("balance error: %s", err.Error())
		w.Write([]byte(errMsg))
		return
	}

	h.lb.Inc(host)
	defer h.lb.Done(host)
	h.hostMap[host].ServeHTTP(w, r)
}

阅读源码产生的疑惑

你好，我最近阅读项目源码的时候发现一个问题，Balancer.Balance方法照理来说应该是负载均衡器选择最终目标服务器的方法，但是只在ServeHTTP方法中被调用，且ServeHTTP方法只在maxAllowedMiddleware中被使用，也就是说如果此处配置文件中config.MaxAllowed配置为0，那么负载均衡器就无法使用

if config.MaxAllowed > 0 {
    router.Use(maxAllowedMiddleware(config.MaxAllowed))
}

请问下这个是不是一个bug？