Redis Weighted Pool

This is a simple Promise based multi-channel weighted round robin pool implementation that leverages Redis sorted set and list.

Requirements

You will need Redis server running.

Installation

npm install redis-weighted-pool
yarn add redis-weighted-pool

Test

The test script in package.json preprocesses the .ts file and then executes.

npm test

Usage

The source was written in Typescript, yet it compiles to Javascript (npm run build). You can use in ES5 or later supported environments. The following code snippets are implemented in the __tests__ folder.

Quick start (Node)

const pool = require('redis-weighted-pool');

const config = pool.RedisConfig("localhost", 6379, null, null);

const myPool = new pool.RedisWeightedPool(config);

myPool.length("myChannel")
  .then(result => {
    console.log({result});
  })
  .catch(error => {
    console.error({error});
  });

Optional with existing client

If you already have a program with a RedisClient you can pass the client as an optional second parameter.

const myPool = new pool.RedisWeightedPool(null, client);

myPool.length("myChannel")
  .then(result => {
    console.log({result});
  })
  .catch(error => {
    console.error({error});
  });

Typescript

Initialization

import {RedisConfig, IWeightedPool, RedisWeightedPool} from 'redis-weighted-pool';

let config: RedisConfig = new RedisConfig(
    "localhost",
    6379,
    null,
    null
);

let myPool : IWeightedPool<string> = new RedisWeightedPool(config);

Add peers

Promise.all([
    myPool.addPeer("channelId", "peerId1", weight1),
    myPool.addPeer("channelId", "peerId2", weight2),
    myPool.addPeer("channelId", "peerId3", weight3)
])
    .then(values => {
        done();
    })
    .catch(error => {
        done.fail(error);
    });

Get next peer (weighted round robin)

myPool.getNextPeer("channelId")
    .then(result => {
        // expect one of peer Ids to be returned
        expect(result).toBeDefined();
    })
    .catch(error => {
        done.fail(error);
    });

Remove peer from channel

myPool.removePeer("channelId", "peerId1")
    .then(result => {
        // expect peer count to be decreased
        expect(result).toBeDefined();
    })
    .catch(error => {
        done.fail(error);
    });

Reset pool for channel

myPool.reset("channelId")
    .then(result => {
        done();
    })
    .catch(error => {
        done.fail(error);
    });

Check if empty

myPool.isEmpty("channelId")
    .then(result => {
        expect(result).toBeFalsy();
        done();
    })
    .catch(error => {
        done.fail(error);
    });

Get pool length

myPool.length("channelId")
    .then(result => {
        expect(result).toEqual(3);
        done();
    })
    .catch(error => {
        done.fail(error);
    });

Contributing

I haven't thought that far ahead yet. I needed this for my project and wanted to give back. ;-)

License

MIT (if you enhance it, fork and PR so the community benefits)