happner/lib/system/repl.js

distributed application engine with evented storage and mesh services

var repl = require('repl')
  , net = require('net')
  , fs = require('fs')
;

var running = false;  // one per process
var server, log;

// First Mesh to call repl.start has instance
module.exports.create = function (instance) {

  if (!instance._mesh.config.repl) {
    if (process.env.UNROOT_ON_REPL) delete global.$happner;
    return;
  }

  if (running) return;

  var config = instance._mesh.config.repl;

  running = true;
  log = log || instance.log.createLogger('Repl');
  log.$$TRACE('create()');

  // This occurs before components start.
  // They can remain isolated but repl can still have access to all as follows
  // START_AS_ROOTED=1 UNROOT_ON_REPL=1 node my_mesh_nodes.js

  var happner = global.$happner;

  if (process.env.UNROOT_ON_REPL) delete global.$happner;

  server = net.createServer(function (socket) {

    log.info('connection on %s', config.socket);
    var r = repl.start({
      prompt: instance._mesh.config.name + '> ',
      input: socket,
      output: socket,
      terminal: true,
      ignoreUndefined: (typeof config.ignoreUndefined == 'undefined') ? false : config.ignoreUndefined,
      useGlobal: true,
      useColors: (typeof config.useColors == 'undefined') ? true : config.useColors
    });

    if (happner) r.context.$happner = happner;

    r.context.localnode = instance;

    // default callback stub gets result back across the socket

    r.context.$callback = function TypicalCallbackStub(err, res) {

      if (err) {
        socket.write('ERROR:\n' + (err.stack || err.toString()) + '\n');
        return;
      }
      socket.write('RESULT:\n' + JSON.stringify(res, null, 2) + '\n');
    }

    socket.on('close', function () {
      log.info('connection departed %s', config.socket);
    });

    socket.on('error', function (err) {
    });

  });

  server.listen(config.socket, function () {
    // console.log('ok')
  });

  server.on('error', function (err) {
    log.error('server error', err);
  });

  server.on('listening', function () {
    log.info('listening at %s', config.socket);
  });

  var clearFd = function () {
    if (config.socket) {
      try {
        log.$$DEBUG('deleting %s', config.socket);
        fs.unlinkSync(config.socket);
      } catch (e) {
      }
    }
  }

  process.on('exit', clearFd);

}