nodeway-raft/bin/raft-cli.js

It is an implementation of the Raft consensus algorithm in Nodeway.

#!/usr/bin/env node

const readline = require('readline');
const require2 = require('require-from-url/async');
const colors   = require('colors/safe');

var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    terminal: true
}), ctor = {}, node = {}, related = {}

async function joint(...args) {
    let url = args.shift(),
        op = args.shift();
    if(!ctor[url]) {
        let [API] = await require2([url]);
        ctor[url] = new API;
    }
    return ctor[url][op](...args);
}

async function _join(url) {
    try {
        await joint(url[0], 'join', url[1]);
        console.log(url[0], '->', url[1], 'ok');
    }
    catch(e) {
        console.log(url[0], '->', url[1], colors.red(e.message));
    }
}

async function join(url) {
    let o = await joint(url, 'info');
    for(let v of o.polls) related[v.uuid] = url;
    for(let id in node)
        if(node[id].url===url) id!==o.id && delete node[id];
        else {
            o.polls.find(v => id===v.link) || await _join([url, node[id].url]);
            o.pushs.find(v => id===v.link) || await _join([node[id].url, url]);
        }
    node[o.id] = Object.assign({url}, o);
}

async function _leave(url) {
    try {
        await joint(url[0], 'leave', url[1]);
        console.log(url[0], 'x>', url[2], 'ok');
    }
    catch(e) {
        console.log(url[0], 'x>', url[2], colors.red(e.message));
    }
}

async function leave(url) {
    let ID = Object.keys(node).find(id => node[id].url===url);
    if(!ID) console.log(url, colors.green('not in consensus'));
    else {
        delete node[ID];
        for(let id in node) {
            await _leave([url, id, node[id].url]);
            await _leave([node[id].url, ID, url]);
        }
    }
}

rl.prompt();
rl.on('line', async line => {
    try {
        let word = line.split(/\s+/);
        switch(word[0]) {
        case 'show':
            for(let id in node) await join(node[id].url);
            for(let id in node) show(node[id]);
            break;
        case 'join':
            await join(word[1]);
            break;
        case 'leave':
            await leave(word[1]);
            break;
        case 'follower':
        case 'weakened':
            await joint(word[1], word[0]);
            break;
        case 'client':
            let result = await joint(word[1], 'client', JSON.parse(word.slice(2).join(' ')));
            console.log('result:', result);
        case '':
            break;
        case 'quit':
            process.exit(0);
        default:
            help();
        }
    }
    catch(e) {
        console.log(colors.red(e.message));
    }
    rl.prompt();
}).on('close', () => {
    console.log('quit');
    process.exit(0);
});

function help() {
    console.log('show');
    console.log('join <url>');
    console.log('leave <url>');
    console.log('follower <url>');
    console.log('weakened <url>');
    console.log('client <url> <command>');
    console.log('quit');
}

function show(o) {
    console.log([
        o.url+' ['+o.state+']',
        '  poll:',
        ...o.polls.map(v => '    '+v.url+' ['+!!v.link+']'),
        '  push:',
        ...o.pushs.map(v => '    '+related[v.uuid]+' ['+!!v.link+']')
    ].join('\n'));
}