node-stressful-journey

A tool for stress testing user journeys through APIs

Installation

npm install -g stressful-journey

Configuration

To execute a stress test, you need to provide the journey to test. This is specified as a JS module which exports an array of steps (see test/example.js for an example).

type: 'request'

The most common step is a request. An HTTP request will be issued and the step will only succeed if the status code is 200, the content-type is application/json and the response is valid JSON. A simple example is -

  {
    type: 'request',
    options: 'http://localhost/hello'
  }

The options value is passed to http.request. N.B. options.agent will always be set to false to prevent connection pooling.

It is also possible to specify a factory method if you want to e.g. template the URL -

  var prefix = 'http://localhost/hello';
  // ...
  options: function(ctx) {
    return prefix + '/hello';
  }

The function will be called once per simulated user per run. The ctx argument is described below.

If you want to post data or modify the request in other ways, you can specify a function as the request value -

  {
    type: 'request',
    options: {
      hostname: 'localhost',
      path: '/echo',
      method: 'POST'
    },
    request: function(ctx, req) {
      req.setHeader('Content-Type', 'application/json');
      req.end(JSON.stringify({hello:'world'}));
    }

The req argument is an http.ClientRequest. N.B. you must manually req.end() the request if you provide a request value otherwise the request will not be sent.

Likewise if you want to validate the JSON response you can specify a function as the response value -

  {
    type: 'request',
    options: 'http://localhost/hello',
    response: function(ctx, res) {
      if (res.hello !== 'world') {
        throw new Error('Failed to validate response');
      }
    }
  }

The res argument is an http.IncommingMessage. Any errors thrown here will be recorded and cause the step to fail.

It is also possible to specify a custom timeout for the request -

  {
    type: 'request',
    timeout: 1000, // ms
    options: 'http://localhost/hello'
  }

If not specified a default value of 60 seconds will be used.

type: 'wait'

A wait step causes the journey to pause for the specified duration of milliseconds -

  {
    type: 'wait',
    duration: 100
  }

duration also accepts a function -

  {
    type: 'wait',
    duration: function(ctx) {
      return ctx.stepIndex * 100;
    }
  }

type: 'custom'

A custom step simply calls the configured handler -

  {
    type: 'custom',
    handler: function(ctx) {
      // do something
    }
  }

Any errors thrown here will be recorded and cause the step to fail.

Also supports async operation if a second argument is specified by the handler. In this case errors should be specified as the argument to the callback.

ctx

ctx is an object unique to each simulated user which can be used to store values between steps or functions within a step. The following properties are automatically added -

• uuid - a RFC4122 v4 UUID
• index - the index of the simulated user
• stepIndex - the index of the currently executing step
• step - the currently executing step (i.e. ctx.steps[ctx.stepIndex])
• deltas - an array of timing results for the steps completed so far

Other supported types are wait and custom, see the code (src/handlers) for usage.

Running

Once you have a journey defined, you can run the stress test using -

stressful-journey journey.js [count=1] [delay=0] [randomisation=0]

• count - the number of users to simulate
• delay/ransomisation - allows control of ramp-up (1 - Math.random() * randomisation) * delay