instrumentor v1.1.5

Overview

instrumentor is intended to make it super easy to wrap modules in additional behavior.

instrumentor only works for modules that expose a single function which returns a promise.

How to use

First we need to get an instrumentor:

  var instrumentor = require('instrumentor')

Add instruments

Call use to add an instrument.

PLEASE NOTE the instrument list is global

  var logger   = require('logging_module')
  var profiler = require('profiler_module')

  instrumentor.use(logger)
  instrumentor.use(profiler)

Instrument a module

the instrument method returns an instrumented module, wrapped in all used instruments. The returned module behaves as expected - instrument's behaviors are transparent to the caller.

  var instrumented_module = instrumentor.instrument('raw_module')

  var raw_module_output = instrumented_module(args)

What is an instrument?

An instrument is module defines some behavior around promise events. instruments for not need to return a promise - they simply need to understand how to handle promise events (resolve, reject, and update) as well as the request event. request is the event that kicks off a module's invokation.