balancer is a layer 7 load balancer that supports http and https, and it is also a go library that implements load balancing algorithms.

It currently supports load balancing algorithms:

• round-robin
• random
• power of 2 random choice
• consistent hash
• consistent hash with bounded
• ip-hash
• least-load

First download the source code of balancer:

> git clone https://github.com/zehuamama/balancer.git

compile the source code:

> cd ./balancer

> go build

Balancer needs to configure the config.yaml file, see config.yaml :

and now, you can execute balancer, the balancer will print the ascii diagram and configuration details:

> ./balancer

___ _ _  _ _   _ ___  ____ _    ____ _  _ ____ ____ ____ 
 |  | |\ |  \_/  |__] |__| |    |__| |\ | |    |___ |__/ 
 |  | | \|   |   |__] |  | |___ |  | | \| |___ |___ |  \                                        

Schema: http
Port: 8089
Health Check: true
Location:
        Route: /
        Proxy Pass: [http://192.168.1.1 http://192.168.1.2:1015 https://192.168.1.2 http://my-server.com]
        Mode: round-robin

balancer will perform health check on all proxy sites periodically. When the site is unreachable, it will be removed from the balancer automatically . However, balancer will still perform health check on unreachable sites. When the site is reachable, it will add it to the balancer automatically.

balancer is also a go library that implements load balancing algorithms, it can be used alone as an API, you need to import it into your project first:

> go get github.com/zehuamama/balancer/balancer

Build the load balancer with balancer.Build:

hosts := []string{
	"http://192.168.11.101",
	"http://192.168.11.102",
	"http://192.168.11.103",
	"http://192.168.11.104",
}

lb, err := balancer.Build(balancer.P2CBalancer, hosts)
if err != nil {
	return err
}

and you can use balancer like this:

clientAddr := "172.160.1.5"  // request IP
	
targetHost, err := lb.Balance(clientAddr) 
if err != nil {
	log.Fatal(err)
}
	
lb.Inc(targetHost)
defer lb.Done(targetHost)

// route to target host

each load balancer implements the balancer.Balancer interface:

type Balancer interface {
	Add(string)
	Remove(string)
	Balance(string) (string, error)
	Inc(string)
	Done(string)
}

currently supports the following load balancing algorithms:

const (
	IPHashBalancer         = "ip-hash"
	ConsistentHashBalancer = "consistent-hash"
	P2CBalancer            = "p2c"
	RandomBalancer         = "random"
	R2Balancer             = "round-robin"
	LeastLoadBalancer      = "least-load"
	BoundedBalancer        = "bounded"
)

If you are interested in contributing to balancer, please see here: CONTRIBUTING

balancer is licensed under the term of the BSD 2-Clause License