index.js

require('clarify');
require('trace');
const Gpio = require('pigpio').Gpio;
const readFileSync = require('fs').readFileSync;
const writeFileSync = require('fs').writeFileSync;
const join = require('path').join;
const { spawn } = require('child_process');
const pify = require('util').promisify;
const rimraf = pify(require('rimraf'));
const promiseRetry = require('promise-retry');
const exitHook = require('exit-hook');

const errorled = new Gpio(20, { mode: Gpio.OUTPUT });
const statusled = new Gpio(21, { mode: Gpio.OUTPUT });

// init leds
statusled.pwmWrite(0);
errorled.pwmWrite(0);

exitHook(() => {
  statusled.pwmWrite(0);
  errorled.pwmWrite(255);
});

const usbPath = '/media/pi/PISTICK';
const logError = (error) => {
  try {
    writeFileSync(join(usbPath, 'errors.txt'), error, { flag: 'a' });
    console.error(error);
  } catch (e) {
    console.error(`Failed to write out error to drive: ${e}`);
    writeFileSync(join('/home/pi', 'errors.txt'), error, { flag: 'a' });
  }
};

process.on('uncaughtException', (error) => {
  setLightState(errorled, 'slowFlash');
  setLightState(statusled, 'off');
  logError(error);
});

const currentInterval = {};
const setLightState = (led, state) => {
  const flash = (speed) => {
    let dutyCycle = 0;
    if (currentInterval[led]) clearInterval(currentInterval[led]);
    currentInterval[led] = setInterval(() => {
      led.pwmWrite(dutyCycle);

      if (dutyCycle === 0) {
        dutyCycle = 255;
      } else {
        dutyCycle = 0;
      }
    }, speed);
  };

  switch (state) {
    case 'slowFlash':
      flash(500);
      break;
    case 'fastFlash':
      flash(200);
      break;
    case 'on':
      if (currentInterval[led]) clearInterval(currentInterval[led]);
      led.pwmWrite(255);
      break;
    case 'off':
      if (currentInterval[led]) clearInterval(currentInterval[led]);
      led.pwmWrite(0);
      break;
    default:
  }
};
let feedPrinter;
setLightState(statusled, 'slowFlash');
let prom = Promise.resolve();
const settings = JSON.parse(readFileSync(join(usbPath, 'settings.json')));
if (settings.wifi) {
  console.log('Connecting to wifi');
  prom = promiseRetry((retry) => {
    return new Promise((resolve, reject) => {
      const nmcli = spawn('nmcli', ['-w', '90', 'device', 'wifi', 'connect', settings.wifi.ssid, 'password', settings.wifi.password]);
      nmcli.stdout.on('data', (data) => {
        console.log(`${data}`);
      });
      let errMsg = '';
      nmcli.stderr.on('data', (data) => {
        errMsg += data;
      });

      nmcli.on('close', (code) => {
        if (code > 0) return reject(new Error(`wifi error ${code}: ${errMsg}`));
        resolve();
      });
    }).catch((e) => retry(e));
  });
}
prom.then((stuff) => {
  console.log('Updating');
  setLightState(statusled, 'fastFlash');
  // root uid update only works on plain install
  // delete hack to make update work
  return rimraf(join('node_modules', 'feed-printer'))
    .then(() => rimraf(join('package-lock.json')))
    .then(() => {
      return new Promise(function (resolve, reject) {
        const npmu = spawn('npm', ['--unsafe-perm', 'install']);
        npmu.stdout.on('data', (data) => {
          console.log(`${data}`);
        });
        let errMsg = '';
        npmu.stderr.on('data', (data) => {
          errMsg += data;
        });

        npmu.on('close', (code) => {
          if (code > 0) return reject(new Error(`Self update failed with code ${code}: ${errMsg}`));
          resolve();
        });
      });
    });
}).then(() => {
  feedPrinter = require('feed-printer');
}).then(() => {
  setLightState(statusled, 'on');
  console.log('Starting');
  // start feed-printer
  let retries = 1;
  let execTime = Date.now();
  const keepItFed = () => {
    feedPrinter.saveEmitter.on('saving', setLightState.bind(null, errorled, 'on'));
    feedPrinter.saveEmitter.on('saved', setLightState.bind(null, errorled, 'off'));
    if (retries && retries < 500) {
      feedPrinter.start(join(usbPath, 'articlesdb.json'), settings.printer)
        .catch((error) => {
          if (execTime - Date.now() < 500) {
            retries = null;
          } else {
            execTime = Date.now();
            retries += 1;
          }
          logError(error);
          keepItFed();
        });
    } else {
      setLightState(errorled, 'slowFlash');
      setLightState(statusled, 'off');
    }
  };
  keepItFed();
}).catch((error) => {
  setLightState(errorled, 'slowFlash');
  setLightState(statusled, 'off');
  logError(error);
});