load-balancer

load-balancer

Introduction

This project is a simple layer 7 load balancer written in Go, supports both http and https scheme, and implements several common load balancing algorithms. Note that not stable for production use, just for personal practice.

Highlights

It currently supports round-robin, random, consistent-hash, ip-hash and least-load algorithms.

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

Getting Started

Build and run

Clone the source code:

git clone https://github.com/lunarwhite/load-balancer.git

You should specific the config.yaml file first, example see config.yaml:

schema: http # support `http` and `https`
port: 8089 # port for balancer
location: # route matching for reverse proxy
  - pattern: /
    proxy_pass: # URLs of the reverse proxy
      - "https://192.168.1.1"
      - "https://192.168.1.2"
      - "https://192.168.1.3"
      - "https://192.168.1.4"
    balance_algo: round-robin # supprt `round-robin`,`random`, `ip-hash, `consistent-hash`, `least-load`
ssl_certificate: # your ssl certificate
ssl_certificate_key: # your ssl certificate key
max_req_allowed: 100 # The max number of requests that the balancer can handle at the same time, 0 refers to no limit
enable_health_check: true
health_check_interval: 3 # second

Then, run commands to build:

cd ./load-balancer
go build

Execute load-balancer, it will print the configuration details:

$ ./load-balancer

Schema: http
Port: 8089
Location:
        Route: /
        Proxy Pass: [https://192.168.1.1 https://192.168.1.2 https://192.168.1.3 https://192.168.1.4]
        Algo: round-robin
Enable Health Check: true

API Usage

You can use it as a third-party Go lib in your project.

go get github.com/lunarwhite/load-balancer/balancer

Build the load balancer with balancer.Build:

hosts := []string{
	"http://192.168.10.102",
	"http://192.168.10.103",
	"http://192.168.10.104",
	"http://192.168.10.105",
}

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

Then, you can use load-balancer like this:

clientAddr := "172.160.10.2"  // 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)
}

Contributing

Contributions are welcome. If you are open source newcomer, you can follow this guide by GitHub.

Report Vulnerability

If you come across a security related issue, please open an issue.

License

This project is licensed under the term of the MIT License.