SLB

README

SLB (Simple Load Balancer) ver 0.1.0

It's a Simple Load Balancer, inspired by sslb(https://github.com/eduardonunesp/sslb), a Super Simple Loader Balancer. SLB improved sslb , so it's no super simple anymore, just simple.

Features

• Http proxy
• Rest API
• Single binary with no other dependencies for easy deployment
• Dynamic reloading without restart (SLB reload)
• Really easy to configure, just a little JSON file
• Support to WebSockets

Install

To install:

go get github.com/linsheng9731/SLB
cd $GOPATH/src/github.com/linsheng9731/SLB
go install

Don't forget to create your configuration file config.json at the same directory of project and run it.

Example (config.json)

{
  "general": {
    "maxProcs": 4,
    "workerPoolSize": 1
  },

  "frontends" : [
    {
      "name" : "Front1",
      "host" : "127.0.0.1",
      "port" : 9000,
      "route" : "/dir",
      "timeout" : 5000,
      "backends" : [
        {
          "name" : "Back1",
          "address" : "http://127.0.0.1:9001",
          "heartbeat" : "http://127.0.0.1:9001",
          "inactiveAfter" : 3,
          "heartbeatTime" : 5000,
          "retryTime" : 5000
        }
      ]
    },
    {
      "name" : "Front2",
      "host" : "127.0.0.1",
      "port" : 9003,
      "route" : "/",
      "timeout" : 5000,
      "backends" : [
        {
          "name" : "Back1",
          "address" : "http://127.0.0.1:9002",
          "heartbeat" : "http://127.0.0.1:9002",
          "inactiveAfter" : 3,
          "heartbeatTime" : 5000,
          "retryTime" : 5000
        }
      ]
    }
  ]
}

Usage

Type slb -h for the command line help

After the configuration file completed you can type only slb to start SLB with verbose mode, that command will log the output from SLB in console. That will print something like that:

2017/09/26 17:54:45 Start SLB (LbServer)
2017/09/26 17:54:45 Create worker pool with [1]
2017/09/26 17:54:45 Prepare to run server ...
2017/09/26 17:54:45 Setup and check configuration
2017/09/26 17:54:45 Setup ok ...
2017/09/26 17:54:45 Api server listen on 127.0.0.1:9292
2017/09/26 17:54:45 Start frontend http server [Front1] at [127.0.0.1:9000]
2017/09/26 17:54:45 Start frontend http server [Front2] at [127.0.0.1:9003]
2017/09/26 17:54:45 Backend active [Back1]

Configuration options

• general:

  • maxProcs: Number of processors used by Go runtime (default: Number of CPUS)
  • workerPoolSize: Number of workers for processing request (default: 10)
  • gracefulShutdown: Wait for the last connection closed, before shutdown (default: true)
  • websocket: Ready for respond websocket connections (default: true)
  • rpchost: Address to expose the internal state (default: 127.0.0.1)
  • rpcport: Port to expose the internal state (default: 42555)
  • apihost: Http api address (default: 127.0.0.1)
  • apiport: Http api address port (default: 9292)

• frontends:

  • name: Just a identifier to your front server (required)
  • host: Host address that serves the HTTP front (required)
  • port: Port address that serves the HTTP front (required)
  • route: Route to receive the traffic (required)
  • timeout: How long can wait for the result (ms) from the backend (default: 30000ms)

• backends:

  • name: Just a identifier (required)
  • address: Address (URL) for your backend (required)
  • hearbeat: Address to send Head request to test if it's ok (required)
  • hbmethod: Method used in request to check the heartbeat (default: HEAD)
  • inactiveAfter: Consider the backend inactive after the number of checks (default: 3)
  • activeAfter: Consider the backend active after the number of checks (default: 1)
  • heartbeatTime: The interval to send a "ping" (default: 30000ms)
  • retryTime: The interval to send a "ping" after the first failed "ping" (default: 5000ms)

Rest API

• http://apihost:apiport/health-check (deafult: http://127.0.0.1:9292/health-check)
• http://apihost:apiport/config (deafult: http://127.0.0.1:9292/config)
• http://apihost:apiport/status (deafult: http://127.0.0.1:9292/status)

Road map

v0.2

• Configurations check
• Internal status and metrics http api
• WebUI

v0.3

• Cache
• HTTP/2 support
• HTTPS support

v0.4

• Integration marathon as backend

If you have any suggestion don't hesitate to open an issue, pull requests are welcome too.

LICENSE

Copyright (c) 2017, Lin Shengsheng All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name of slb nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.