gethdev.js

/* global web3 */

// https://github.com/amacneil/gethdev
var minHeight = 0;

// minimum etherbase balance we should mine
var MIN_BALANCE = web3.toWei(web3.toBigNumber(100), 'ether');

// number of threads to mine with
var THREADS = 1;

// number of blocks to mine on top of new transactions before stopping
var CONFIRMATIONS = 5;

function log(str) {
  console.log('[gethdev] ' + str);
}

/**
 * Start the miner if it is not already running
 */
function startMiner() {
  if (!web3.eth.mining) {
    log('Starting miner');
    web3.miner.start(THREADS);
  }
}

/**
 * Stop the miner if it is running
 */
function stopMiner() {
  if (web3.eth.mining) {
    log('Stopping miner');
    web3.miner.stop();
  }
}

/**
 * Start or stop the miner if necessary
 */
function checkStatus() {
  // if etherbase balance is too low, start mining
  if (web3.eth.getBalance(web3.eth.coinbase).lessThan(MIN_BALANCE)) {
    startMiner();
    return;
  }

  // if there are any pending transactions, start mining
  if (web3.eth.getBlock('pending').transactions.length > 0) {
    minHeight = web3.eth.blockNumber + CONFIRMATIONS;

    startMiner();
    return;
  }

  if (web3.eth.blockNumber > minHeight) {
    // nothing to do, pause mining for now
    stopMiner();
  }
}

// create the first account (with blank password) if necessary
if (web3.personal.listAccounts.length === 0) {
  log('Creating etherbase account');
  web3.personal.newAccount('');
}

web3.eth.filter('latest', checkStatus);
web3.eth.filter('pending', checkStatus);
startMiner();