get the report on active local Ethereum clients (client version and latest block)

ethInquireClients.js

#!/usr/bin/env node
var colors = require('colors'); // npm install colors
var moment = require('moment'); // npm install moment
var Web3 = require('web3'); // npm install web3

let port = process.argv[2];

function tryWeb3(port) {
  let web3 = new Web3();
  web3.setProvider(new web3.providers.HttpProvider(`http://localhost:${port}`));
  try {
    const dummy = web3.version.node;
    return web3;
  } catch (e) {}
  return false;
}

function latestBlock(web3) {
  return new Date(web3.eth.getBlock(web3.eth.blockNumber).timestamp * 1000);
}

function isRecent(web3) {
  return (Date.now() - latestBlock(web3)) / 1000.0 < 40;
}

function isOld(web3) {
  return (Date.now() - latestBlock(web3)) / 1000.0 > 86400;
}

function inquireClient(client, port) {
  let web3 = tryWeb3(port);
  if (web3) {
    web3.setProvider(new web3.providers.HttpProvider(`http://localhost:${port}`));
    const mark = isRecent(web3) ? colors.green(' ✓') : isOld(web3) ? colors.red(' ✗') : '';
    const version = web3.version.node;

    let msg;
    if (client) {
      msg = version.match(new RegExp(client, 'i')) ? colors.green(client) : colors.red(`*not* ${client} on ${port}`);
    } else {
      msg = colors.green(`port ${port}`);
    }
    console.log(`${msg} ${moment(latestBlock(web3)).fromNow()}${mark} ${colors.gray(version)}`);
  } else if (!client) {
    console.log(colors.red(`no Ethereum client running on port ${port}`));
  }
}

inquireClient('geth', 8545);
inquireClient('parity', 8546);
inquireClient('testrpc', 8550);

if (port) {
  inquireClient('', port);
}