launcher.js

/*******************************************************************************
 * Copyright 2014, 2015 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
'use strict';

// argv[0] should be 'node',
// argv[1] the name of this file.
// argv[2] the module to run

// Note: This launcher does not support all invocation modes
//       Not supported: use of lib/_third_party_main.js
//                      node -e <script_string>,
//                      <some_stream> | node
//                      node < <script_file>

// Remove argv[1] so it looks like the module is executed directly
// Note: This also causes runMain() to run the correct module
// Note: If you are using node-hc debug, you need to skip over this
//       launcher code until you hit your application code
process.argv.splice(1, 1);
delete process.mainModule;

// Check early for unsupported mode of invocation, so we don't start
// appmetrics
var tty = require('tty');
if (process.argv.length <= 1 && !(process.forceRepl || tty.isatty(0))) {
  var err = new Error('node-hc does not support reading a script from stdin');
  throw err;
}

// Start the agent
var path = require('path');
var dir = path.dirname(module.filename);
var agent_module = path.join(dir, 'index.js');
if (process.argv.length > 1) {
  /* Remove any leading "./" in front of the name of the script - e.g. ./app.js => app.js  */
  if (process.argv[1].indexOf('./') === 0) process.argv[1] = process.argv[1].substring(2, process.argv[1].length);

  /* Mock the main module for the benefit of the agent (just the bit it needs) */
  process.mainModule = { filename: require.resolve(process.argv[1]) };
}
var agent = require(agent_module);
agent.start();
delete process.mainModule;

if (process.argv.length > 1) {
  // Start module
  require('module').runMain();
} else if (process._forceRepl || tty.isatty(0)) {
  // Start REPL
  require('repl').start({});
} else {
  // Should not happen, but just in case write a message
  throw new Error('node-hc does not support this method of invocation');
}