mStream/modules/db-management/database-master.js

const child = require('child_process');
const fe = require('path');
const mstreamReadPublicDB = require('../db-read/database-public-loki.js');
const winston = require('winston');

exports.setup = function (mstream, program) {
  // Load in API endpoints
  mstreamReadPublicDB.setup(mstream, program);

  // Var that keeps track of DB scans going on
  var isScanning = false;

  // Get db status
  mstream.get('/db/status', function (req, res) {
    // Get number of files in DB
    mstreamReadPublicDB.getNumberOfFiles(req.user.vpaths, function (numOfFiles) {
      res.json({
        totalFileCount: numOfFiles,
        dbType: 'default',
        locked: isScanning
      });
    });
  });

  // Scan library
  mstream.get('/db/recursive-scan', function (req, res) {
    runScan();
    res.status((scan.error === true) ? 555 : 200).json({ status: scan.message });
  });


  function scanIt(directory, vpath, callback) {
    var parseFlag = false;

    // Prepare JSON load for forked process
    const jsonLoad = {
      directory: directory,
      vpath: vpath,
      dbSettings: program.database_plugin,
      albumArtDir: program.albumArtDir,
      skipImg: program.database_plugin.skipImg ? true : false,
      saveInterval: program.database_plugin.saveInterval ? program.database_plugin.saveInterval : 250,
      pause: program.database_plugin.pause ? program.database_plugin.pause  : false
    }

    const forkedScan = child.fork(fe.join(__dirname, 'database-default-manager.js'), [JSON.stringify(jsonLoad)], { silent: true });
    winston.info(`File scan started on ${jsonLoad.directory}`);
    forkedScan.stdout.on('data', (data) => {
      try {
        const parsedMsg = JSON.parse(data, 'utf8');
        winston.info(`File scan message: ${parsedMsg.msg}`);
        // TODO: Ideally, if there are no changes to the DB we should not be reloading it. Ideally...
        if(parsedMsg.loadDB === true) {
          parseFlag = true;
          mstreamReadPublicDB.loadDB();
        }
      } catch (error) {
        winston.info(`File scan message: ${data}`);
        return;
      }
    });
    forkedScan.stderr.on('data', (data) => {
      winston.error(`File scan error: ${data}`);
    });
    forkedScan.on('close', (code) => {
      isScanning = false;
      if(parseFlag === false) {
        mstreamReadPublicDB.loadDB();
      }
      winston.info(`File scan completed with code ${code}`);
      callback();
    });
  }


  // Scan on startup
  function* bootScan() {
    // Loop through list of users
    for (let vpath in program.folders) {

      yield scanIt( program.folders[vpath].root, vpath, () => {
        bootScanGenerator.next();
      });
    }
  }


  var bootScanGenerator;
  function runScan() {
    // Check that scan is not already in progress
    if (isScanning === true) {
      return { error: true, message: 'Scan in Progress' }; // Need to return a status
    }

    // Lock user
    isScanning = true;

    bootScanGenerator = bootScan();
    bootScanGenerator.next();

    return { error: false, message: 'Scan Started' };
  }

  runScan();

  if (program.database_plugin.interval) {
    setInterval(() => runScan(), program.database_plugin.interval * 60 * 60 * 1000);
  }
}