loadbalancer

Round-robin http load balancer

Proxy incoming request to provided servers bucket with round-robin.
Every 5 sec check server's availability.
Every STALE_TIMEOUT minutes delete unreachable servers from bucket.

Configuration

Application supports configuration via environment variables:

PORT=8000 (default 8000)
STALE_TIMEOUT=60 (default 60 - minutes)
ADDRS=http://service-1:9000,http://service-2:9001 (default empty)

Installation

With docker

$> docker pull freundallein/go-lb

With source

$> git clone git@github.com:freundallein/loadbalancer.git
$> cd loadbalancer
$> make build

Usage

Docker-compose

version: "3.5"

networks:
  network:
    name: example-network
    driver: bridge

services:
  loadbalancer:
    image: freundallein/go-lb:latest
    container_name: loadbalancer
    restart: always
    environment: 
      - PORT=8000
      - ADDRS=http://service-one:8000,http://service-two:8000,http://service-three:8000
      - STALE_TIMEOUT=1
    networks: 
      - network
    ports:
      - 8000:8000

  service-one:
    image: crccheck/hello-world
    container_name: hello-world-one
    restart: always
    networks: 
      - network

  service-two:
    image: crccheck/hello-world
    container_name: hello-world-two
    restart: always
    networks: 
      - network

  service-three:
    image: crccheck/hello-world
    container_name: hello-world-three
    restart: always
    networks: 
      - network

Metrics

Default prometheus metrics are available on /metrics
Custom metric - lb_bucket_size 1 - represents the total number of servers in bucket

Healthcheck

Service healthcheck is avaliable on /healthz.
Return 200 if there are more then 0 servers in bucket esle 500.

Good luck.