index.js

'use strict'

// Record opening times before loading any other files.
var preAgentTime = process.uptime()
var agentStart = Date.now()

// Load unwrapped core now to ensure it gets the freshest properties.
require('./lib/util/unwrapped-core')

var featureFlags = require('./lib/feature_flags').prerelease
var logger = require('./lib/logger')
var psemver = require('./lib/util/process-version')


var agentVersion = require('./package').version
logger.info(
  "Using New Relic for Node.js. Agent version: %s; Node version: %s.",
  agentVersion, process.version
)

if (require.cache.__NR_cache) {
  logger.warn(
    'Attempting to load a second copy of newrelic from %s, using cache instead',
    __dirname
  )
  if (require.cache.__NR_cache.agent) {
    require.cache.__NR_cache.agent.recordSupportability('Agent/DoubleLoad')
  }
  module.exports = require.cache.__NR_cache
} else {
  initialize()
}

function initialize() {
  logger.debug('Loading agent from %s', __dirname)
  var agent = null
  var message = null

  try {
    logger.debug(
      'Process was running %s seconds before agent was loaded.',
      preAgentTime
    )

    // TODO: Update this check when Node v4 is deprecated.
    if (psemver.satisfies('<4.0.0')) {
      message = "New Relic for Node.js requires a version of Node equal to or\n" +
                "greater than 4.0.0. Not starting!"

      logger.error(message)
      throw new Error(message)
    }

    logger.debug("Current working directory at module load is %s.", process.cwd())
    logger.debug("Process title is %s.", process.title)
    logger.debug("Application was invoked as %s.", process.argv.join(' '))

    var config = require('./lib/config').getOrCreateInstance()

    // Get the initialized logger as we likely have a bootstrap logger which
    // just pipes to stdout.
    logger = require('./lib/logger')

    if (!config || !config.agent_enabled) {
      logger.info("Module not enabled in configuration; not starting.")
    } else {
      agent = createAgent(config)
      addStartupSupportabilities(agent)
    }
  } catch (error) {
    message = "New Relic for Node.js was unable to bootstrap itself due to an error:"
    logger.error(error, message)

    /* eslint-disable no-console */
    console.error(message)
    console.error(error.stack)
    /* eslint-enable no-console */
  }

  var API = null
  if (agent) {
    API = require('./api')
  } else {
    API = require('./stub_api')
  }

  require.cache.__NR_cache = module.exports = new API(agent)

  // If we loaded an agent, record a startup time for the agent.
  // NOTE: Metrics are recorded in seconds, so divide the value by 1000.
  if (agent) {
    var initDuration = (Date.now() - agentStart) / 1000
    agent.recordSupportability('Application/Opening/Duration', preAgentTime)
    agent.recordSupportability('Application/Initialization/Duration', initDuration)
    agent.once('started', function timeAgentStart() {
      agent.recordSupportability(
        'Application/Registration/Duration',
        (Date.now() - agentStart) / 1000
      )
    })
  }
}

function createAgent(config) {
  /* Only load the rest of the module if configuration is available and the
   * configurator didn't throw.
   *
   * The agent must be a singleton, or else module loading will be patched
   * multiple times, with undefined results. New Relic's instrumentation
   * can't be enabled or disabled without an application restart.
   */
  var Agent = require('./lib/agent')
  var agent = new Agent(config)
  var appNames = agent.config.applications()

  if (config.logging.diagnostics) {
    logger.warn(
      'Diagnostics logging is enabled, this may cause significant overhead.'
    )
  }

  if (appNames.length < 1) {
    var message =
      'New Relic requires that you name this application!\n' +
      'Set app_name in your newrelic.js file or set environment variable\n' +
      'NEW_RELIC_APP_NAME. Not starting!'
    logger.error(message)
    throw new Error(message)
  }

  var shimmer = require('./lib/shimmer')
  shimmer.patchModule(agent)
  shimmer.bootstrapInstrumentation(agent)

  agent.start(function cb_start(error) {
    if (!error) {
      return logger.debug("New Relic for Node.js is connected to New Relic.")
    }

    var errorMessage = "New Relic for Node.js halted startup due to an error:"
    logger.error(error, errorMessage)

    /* eslint-disable no-console */
    console.error(errorMessage)
    console.error(error.stack)
    /* eslint-enable no-console */
  })

  return agent
}

function addStartupSupportabilities(agent) {
  // TODO: After deprecating Node 0.10 and 0.12, simplify this regex.
  // TODO: As new versions come out, make sure to update Angler metrics.
  var nodeMajor = /^v?((?:0\.)?\d+)/.exec(process.version)
  agent.recordSupportability(
    'Version/' + ((nodeMajor && nodeMajor[1]) || 'unknown')
  )

  var configFlags = Object.keys(agent.config.feature_flag)
  for (var i = 0; i < configFlags.length; ++i) {
    var flag = configFlags[i]
    var enabled = agent.config.feature_flag[flag]

    if (enabled !== featureFlags[flag]) {
      agent.recordSupportability(
        'FeatureFlag/' + flag + '/' + (enabled ? 'enabled' : 'disabled')
      )
    }
  }
}