Repository: davidmarkclements/overload-protection
Branch: master
Commit: 340e777990e3
Files: 33
Total size: 101.2 KB

Directory structure:
gitextract_e7w9qjtr/

├── .gitignore
├── .travis.yml
├── LICENSE
├── benchmarks/
│   ├── express/
│   │   ├── excluded.js
│   │   ├── included.js
│   │   └── index.js
│   ├── http/
│   │   ├── excluded.js
│   │   ├── included.js
│   │   └── index.js
│   ├── koa/
│   │   ├── excluded.js
│   │   ├── included.js
│   │   └── index.js
│   └── restify/
│       ├── excluded.js
│       ├── included.js
│       └── index.js
├── demos/
│   ├── express/
│   │   └── index.js
│   ├── http/
│   │   └── index.js
│   ├── koa/
│   │   └── index.js
│   └── restify/
│       └── index.js
├── index.js
├── lib/
│   ├── explain.js
│   ├── express.js
│   ├── http.js
│   ├── koa.js
│   ├── restify.js
│   └── stats.js
├── package.json
├── readme.md
└── test/
    ├── index.js
    └── integration/
        ├── express/
        │   └── index.js
        ├── http/
        │   └── index.js
        ├── koa/
        │   └── index.js
        └── restify/
            └── index.js

================================================
FILE CONTENTS
================================================

================================================
FILE: .gitignore
================================================

# Created by https://www.gitignore.io/api/node

### Node ###
# Logs
logs
*.log
npm-debug.log*
yarn-debug.log*
yarn-error.log*

# Runtime data
pids
*.pid
*.seed
*.pid.lock

# Directory for instrumented libs generated by jscoverage/JSCover
lib-cov

# Coverage directory used by tools like istanbul
coverage

# nyc test coverage
.nyc_output

# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
.grunt

# Bower dependency directory (https://bower.io/)
bower_components

# node-waf configuration
.lock-wscript

# Compiled binary addons (http://nodejs.org/api/addons.html)
build/Release

# Dependency directories
node_modules/
jspm_packages/

# Typescript v1 declaration files
typings/

# Optional npm cache directory
.npm

# Optional eslint cache
.eslintcache

# Optional REPL history
.node_repl_history

# Output of 'npm pack'
*.tgz

# Yarn Integrity file
.yarn-integrity

# dotenv environment variables file
.env


# End of https://www.gitignore.io/api/node


================================================
FILE: .travis.yml
================================================
language: node_js
sudo: false
node_js:
- '8'
- '10'
- '12'
script:
- npm run ci


================================================
FILE: LICENSE
================================================
The MIT License (MIT)

Copyright (c) 2017 David Mark Clements

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



================================================
FILE: benchmarks/express/excluded.js
================================================
'use strict'

var app = require('express')()

app.get('/', function (req, res) {
  res.send('content')
})

module.exports = app


================================================
FILE: benchmarks/express/included.js
================================================
'use strict'

var app = require('express')()
var protect = require('../..')('express')

app.use(protect)

app.get('/', function (req, res) {
  res.send('content')
})

module.exports = app


================================================
FILE: benchmarks/express/index.js
================================================
'use strict'
var autocannon = require('autocannon')

var included = require('./included')
var excluded = require('./excluded')

console.log('express with overload protection:')
included = included.listen(3000)
var instance = autocannon({
  url: 'http://localhost:3000',
  connections: 10,
  pipelining: 1,
  duration: 10
}, function () {
  instance.stop()
  included.close()
  console.log('\nexpress without overload protection:')
  excluded = excluded.listen(3000)
  instance = autocannon({
    url: 'http://localhost:3000',
    connections: 10,
    pipelining: 1,
    duration: 10
  }, function () {
    instance.stop()
    excluded.close()
  })
  autocannon.track(instance, {renderProgressBar: true})
})

// just render results
autocannon.track(instance, {renderProgressBar: true})


================================================
FILE: benchmarks/http/excluded.js
================================================
'use strict'

var http = require('http')
var server = http.createServer(serve)

function serve (req, res) {
  res.end('content')
}

module.exports = server


================================================
FILE: benchmarks/http/included.js
================================================
'use strict'

var http = require('http')
var server = http.createServer(serve)
var protect = require('../..')('http')

function serve (req, res) {
  if (protect(req, res) === true) return
  res.end('content')
}

module.exports = server


================================================
FILE: benchmarks/http/index.js
================================================
'use strict'
var autocannon = require('autocannon')

var included = require('./included')
var excluded = require('./excluded')

console.log('http with overload protection:')
included.listen(3000)
var instance = autocannon({
  url: 'http://localhost:3000',
  connections: 10,
  pipelining: 1,
  duration: 10
}, function () {
  instance.stop()
  included.close()
  console.log('\nhttp without overload protection:')
  excluded.listen(3000)
  instance = autocannon({
    url: 'http://localhost:3000',
    connections: 10,
    pipelining: 1,
    duration: 10
  }, function () {
    instance.stop()
    excluded.close()
  })
  autocannon.track(instance, {renderProgressBar: true})
})

// just render results
autocannon.track(instance, {renderProgressBar: true})


================================================
FILE: benchmarks/koa/excluded.js
================================================
'use strict'

var Koa = require('koa')
var Router = require('koa-router')

var router = new Router()
var app = new Koa()

router.get('/', async function (ctx) {
  ctx.body = 'content'
})

app.use(router.routes())

module.exports = app


================================================
FILE: benchmarks/koa/included.js
================================================
'use strict'

var Koa = require('koa')
var Router = require('koa-router')
var protect = require('../..')('koa')

var router = new Router()
var app = new Koa()

app.use(protect)

router.get('/', async function (ctx) {
  ctx.body = 'content'
})

app.use(router.routes())

module.exports = app


================================================
FILE: benchmarks/koa/index.js
================================================
'use strict'
var autocannon = require('autocannon')

var included = require('./included')
var excluded = require('./excluded')

console.log('koa with overload protection:')
included = included.listen(3000)
var instance = autocannon({
  url: 'http://localhost:3000',
  connections: 10,
  pipelining: 1,
  duration: 10
}, function () {
  instance.stop()
  included.close()
  console.log('\nkoa without overload protection:')
  excluded = excluded.listen(3000)
  instance = autocannon({
    url: 'http://localhost:3000',
    connections: 10,
    pipelining: 1,
    duration: 10
  }, function () {
    instance.stop()
    excluded.close()
  })
  autocannon.track(instance, {renderProgressBar: true})
})

// just render results
autocannon.track(instance, {renderProgressBar: true})


================================================
FILE: benchmarks/restify/excluded.js
================================================
'use strict'

var app = require('restify').createServer({
  name: 'myapp',
  version: '1.0.0'
})

app.get('/', function (req, res) {
  res.send('content')
})

module.exports = app


================================================
FILE: benchmarks/restify/included.js
================================================
'use strict'

var app = require('restify').createServer({
  name: 'myapp',
  version: '1.0.0'
})
var protect = require('../..')('restify')

app.use(protect)

app.get('/', function (req, res) {
  res.send('content')
})

module.exports = app


================================================
FILE: benchmarks/restify/index.js
================================================
'use strict'
var autocannon = require('autocannon')

var included = require('./included')
var excluded = require('./excluded')

console.log('restify with overload protection:')
included = included.listen(3000)
var instance = autocannon({
  url: 'http://localhost:3000',
  connections: 10,
  pipelining: 1,
  duration: 10
}, function () {
  instance.stop()
  included.close()
  console.log('\nrestify without overload protection:')
  excluded = excluded.listen(3000)
  instance = autocannon({
    url: 'http://localhost:3000',
    connections: 10,
    pipelining: 1,
    duration: 10
  }, function () {
    instance.stop()
    excluded.close()
  })
  autocannon.track(instance, {renderProgressBar: true})
})

// just render results
autocannon.track(instance, {renderProgressBar: true})


================================================
FILE: demos/express/index.js
================================================
'use strict'

var app = require('express')()
var protect = require('../..')('express')

app.use(protect)

app.get('/', function (req, res) {
  res.send('content')
})

app.listen(3000, function () {
  var req = require('http').get('http://localhost:3000')

  req.on('response', function (res) {
    console.log('got status code', res.statusCode)
    console.log('retry after', res.headers['retry-after'])

    setTimeout(function () {
      console.log('protect.overload after load', protect.overload)
      var req = require('http').get('http://localhost:3000')

      req.on('response', function (res) {
        console.log('got status code', res.statusCode)

        protect.stop()
        process.exit()
      }).end()
    }, parseInt(res.headers['retry-after'], 10))
  }).end()

  setImmediate(function () {
    console.log('eventLoopDelay after active sleeping', protect.eventLoopDelay)
  })

  sleep(500)
})

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}


================================================
FILE: demos/http/index.js
================================================
'use strict'

var http = require('http')
var server = http.createServer(serve)
var protect = require('../..')('http')

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}

function serve (req, res) {
  if (protect(req, res) === true) return
  res.end('content')
}

server.listen(0, function () {
  var req = http.get(server.address())

  req.on('response', function (res) {
    console.log('got status code', res.statusCode)
    console.log('retry after', res.headers['retry-after'])

    setTimeout(function () {
      console.log('protect.overload after load', protect.overload)
      var req = http.get(server.address())

      req.on('response', function (res) {
        console.log('got status code', res.statusCode)

        protect.stop()
        server.close()
      }).end()
    }, parseInt(res.headers['retry-after'], 10))
  }).end()

  setImmediate(function () {
    console.log('eventLoopDelay after active sleeping', protect.eventLoopDelay)
  })

  sleep(500)
})


================================================
FILE: demos/koa/index.js
================================================
'use strict'

var Koa = require('koa')
var Router = require('koa-router')
var protect = require('../..')('koa')

var router = new Router()
var app = new Koa()

app.use(protect)

router.get('/', async function (ctx) {
  ctx.body = 'content'
})

app.use(router.routes())
app.listen(3000, function () {
  var req = require('http').get('http://localhost:3000')

  req.on('response', function (res) {
    console.log('got status code', res.statusCode)
    console.log('retry after', res.headers['retry-after'])

    setTimeout(function () {
      console.log('protect.overload after load', protect.overload)
      var req = require('http').get('http://localhost:3000')

      req.on('response', function (res) {
        console.log('got status code', res.statusCode)

        protect.stop()
        process.exit()
      }).end()
    }, parseInt(res.headers['retry-after'], 10))
  }).end()

  setImmediate(function () {
    console.log('eventLoopDelay after active sleeping', protect.eventLoopDelay)
  })

  sleep(500)
})

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}


================================================
FILE: demos/restify/index.js
================================================
'use strict'

var app = require('restify').createServer({
  name: 'myapp',
  version: '1.0.0'
})
var protect = require('../..')('restify')

app.use(protect)

app.get('/', function (req, res) {
  res.send('content')
})

app.listen(3000, function () {
  var req = require('http').get('http://localhost:3000')

  req.on('response', function (res) {
    console.log('got status code', res.statusCode)
    console.log('retry after', res.headers['retry-after'])

    setTimeout(function () {
      console.log('protect.overload after load', protect.overload)
      var req = require('http').get('http://localhost:3000')

      req.on('response', function (res) {
        console.log('got status code', res.statusCode)

        protect.stop()
        process.exit()
      }).end()
    }, parseInt(res.headers['retry-after'], 10))
  }).end()

  setImmediate(function () {
    console.log('eventLoopDelay after active sleeping', protect.eventLoopDelay)
  })

  sleep(500)
})

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}


================================================
FILE: index.js
================================================
'use strict'

var loopbench = require('loopbench')

var frameworks = {
  express: require('./lib/express'),
  http: require('./lib/http'),
  koa: require('./lib/koa'),
  restify: require('./lib/restify')
}

var defaults = {
  production: process.env.NODE_ENV === 'production',
  errorPropagationMode: false,
  clientRetrySecs: 1,
  sampleInterval: 5,
  maxEventLoopDelay: 42,
  maxHeapUsedBytes: 0,
  maxRssBytes: 0,
  logging: false,
  logStatsOnReq: false
}

function protect (framework, opts) {
  opts = Object.assign({}, defaults, opts)
  if (typeof framework === 'undefined') {
    throw Error('Please specify a framework')
  }
  if (!(framework in frameworks)) {
    throw Error(opts.integrate + ' not supported.')
  }
  if (opts.maxRssBytes <= 0 && opts.maxHeapUsedBytes <= 0 && opts.eventLoopDelay <= 0) {
    throw Error('At least one threshold (eventLoopDelay, maxHeapUsedBytes, maxRssBytes) should be above 0')
  }
  if (opts.logStatsOnReq && opts.logging === false) {
    throw Error('logStatsOnReq cannot be enabled unless logging is also enabled')
  }
  var update = (opts.maxEventLoopDelay > 0)
    ? function update () {
      profiler.eventLoopOverload = eventLoopProfiler.overLimit
      profiler.eventLoopDelay = eventLoopProfiler.delay
      profiler.overload = profiler.eventLoopOverload ||
          profiler.heapUsedOverload ||
          profiler.rssOverload
    }
    : function update () {
      profiler.overload = profiler.heapUsedOverload || profiler.rssOverload
    }

  if (opts.maxEventLoopDelay > 0) {
    var eventLoopProfiler = loopbench({
      sampleInterval: opts.sampleInterval,
      limit: opts.maxEventLoopDelay
    })

    eventLoopProfiler.on('load', update)
    eventLoopProfiler.on('unload', update)
  }

  var maxHeapUsedBytes = opts.maxHeapUsedBytes
  var maxRssBytes = opts.maxRssBytes

  var timer = (maxHeapUsedBytes > 0 || maxRssBytes > 0) &&
    setInterval(checkMemory, opts.sampleInterval).unref()

  var profiler = {
    overload: false,
    eventLoopOverload: false,
    heapUsedOverload: false,
    rssOverload: false,
    eventLoopDelay: 0,
    maxEventLoopDelay: opts.maxEventLoopDelay,
    maxHeapUsedBytes: opts.maxHeapUsedBytes,
    maxRssBytes: opts.maxRssBytes,
    stop: stop
  }

  var integrate = frameworks[framework](opts, profiler)
  if (Object.setPrototypeOf) {
    Object.setPrototypeOf(profiler, Function.prototype)
    Object.setPrototypeOf(integrate, profiler)
  } else {
    profiler.__proto__ = Function.prototype // eslint-disable-line
    integrate.__proto__ = profiler // eslint-disable-line
  }

  return integrate

  function checkMemory () {
    var mem = process.memoryUsage()
    var heapUsed = mem.heapUsed
    var rss = mem.rss
    profiler.heapUsedOverload = (maxHeapUsedBytes > 0 && heapUsed > maxHeapUsedBytes)
    profiler.rssOverload = (maxRssBytes > 0 && rss > maxRssBytes)
    update()
  }

  function stop () {
    if (eventLoopProfiler) eventLoopProfiler.stop()
    clearInterval(timer)
  }
}

module.exports = protect


================================================
FILE: lib/explain.js
================================================
'use strict'

module.exports = explain

function explain (protect) {
  var explanation = 'Server experiencing heavy load: ('
  var c = 0
  if (protect.eventLoopOverload === true) {
    c += 1
    explanation += 'event loop'
  }
  if (protect.heapUsedOverload === true) {
    explanation += c > 0 ? ', heap' : 'heap'
    c += 1
  }
  if (protect.rssOverload === true) {
    explanation += c > 0 ? ', rss' : 'rss'
  }

  explanation += ')'

  return explanation
}


================================================
FILE: lib/express.js
================================================
'use strict'
module.exports = require('./http')


================================================
FILE: lib/http.js
================================================
'use strict'

var explain = require('./explain')
var OverloadProtectionStats = require('./stats')

module.exports = http

function http (opts, protect) {
  var clientRetrySecs = opts.clientRetrySecs
  var sendRetryHeader = clientRetrySecs > 0
  var logStatsOnReq = opts.logStatsOnReq
  var logging = opts.logging
  var loggingOn = typeof logging === 'string' || typeof logging === 'function'
  var log4jLogging = typeof logging === 'string'
  var errorPropagationMode = opts.errorPropagationMode
  var production = opts.production
  var expose = !production

  return overloadProtection

  function overloadProtection (req, res, next) {
    if (logStatsOnReq) {
      const stats = new OverloadProtectionStats(
        protect.overload,
        protect.eventLoopOverload,
        protect.heapUsedOverload,
        protect.rssOverload,
        protect.eventLoopDelay,
        protect.maxEventLoopDelay,
        protect.maxHeapUsedBytes,
        protect.maxRssBytes
      )
      if (log4jLogging) req.log && req.log[logging] && req.log[logging](stats)
      else logging(stats)
    }
    if (protect.overload === true) {
      res.statusCode = 503
      if (sendRetryHeader) res.setHeader('Retry-After', clientRetrySecs)
      if (loggingOn) {
        if (log4jLogging) req.log && req.log[logging] && req.log[logging](explain(protect))
        else logging(explain(protect))
      }
      if (errorPropagationMode && typeof next === 'function') {
        var err = Error(explain(protect))
        err.expose = expose
        err.statusCode = 503
        next(err)
        return
      }

      res.end(production ? 'Service Unavailable' : explain(protect))

      if (arguments.length < 3) return true
      else return
    }
    if (arguments.length >= 3 && typeof next === 'function') next()
    else return false
  }
}


================================================
FILE: lib/koa.js
================================================
'use strict'
module.exports = koa

var explain = require('./explain')
var OverloadProtectionStats = require('./stats')

function koa (opts, protect) {
  var clientRetrySecs = opts.clientRetrySecs
  var sendRetryHeader = clientRetrySecs > 0
  var logStatsOnReq = opts.logStatsOnReq
  var logging = opts.logging
  var loggingOn = typeof logging === 'string' || typeof logging === 'function'
  var log4jLogging = typeof logging === 'string'
  var errorPropagationMode = opts.errorPropagationMode
  var production = opts.production
  var expose = !production

  return overloadProtection

  function overloadProtection (ctx, next) {
    if (logStatsOnReq) {
      const stats = new OverloadProtectionStats(
        protect.overload,
        protect.eventLoopOverload,
        protect.heapUsedOverload,
        protect.rssOverload,
        protect.eventLoopDelay,
        protect.maxEventLoopDelay,
        protect.maxHeapUsedBytes,
        protect.maxRssBytes
      )
      if (log4jLogging) ctx.log && ctx.log[logging] && ctx.log[logging](stats)
      else logging(stats)
    }
    if (protect.overload === true) {
      if (sendRetryHeader) ctx.set('Retry-After', clientRetrySecs)
      if (loggingOn) {
        if (log4jLogging) ctx.log && ctx.log[logging] && ctx.log[logging](explain(protect))
        else logging(explain(protect))
      }
      if (errorPropagationMode) {
        var err = Error(explain(protect))
        err.status = 503
        err.expose = expose

        // if exposing to client in dev,
        // we also want to output
        // the error in console
        if (err.expose) {
          ctx.app.emit('error', Error(explain(protect)), ctx)
        }

        throw err
      }
      ctx.status = 503

      ctx.res.end(production ? 'Service Unavailable' : explain(protect))
      return
    }
    return next()
  }
}


================================================
FILE: lib/restify.js
================================================
'use strict'
module.exports = require('./http')


================================================
FILE: lib/stats.js
================================================
function OverloadProtectionStats (overload, eventLoopOverload, heapUsedOverload, rssOverload, eventLoopDelay, maxEventLoopDelay, maxHeapUsedBytes, maxRssBytes) {
  this.overload = overload
  this.eventLoopOverload = eventLoopOverload
  this.heapUsedOverload = heapUsedOverload
  this.rssOverload = rssOverload
  this.eventLoopDelay = eventLoopDelay
  this.maxEventLoopDelay = maxEventLoopDelay
  this.maxHeapUsedBytes = maxHeapUsedBytes
  this.maxRssBytes = maxRssBytes
}

module.exports = OverloadProtectionStats


================================================
FILE: package.json
================================================
{
  "name": "overload-protection",
  "version": "1.2.3",
  "main": "index.js",
  "scripts": {
    "test": "tap test",
    "lint": "standard",
    "ci": "npm run lint && npm run cov",
    "cov": "tap --cov test",
    "covr": "tap --coverage-report=html test",
    "benchmarks": "ls benchmarks | while read l; do node benchmarks/$l; done"
  },
  "pre-commit": [
    "test",
    "lint"
  ],
  "keywords": [
    "load shedding",
    "overload protection",
    "production monitoring",
    "503",
    "Service Unavailable",
    "Server Unavailable",
    "HTTP 503",
    "heavy load",
    "load",
    "protection",
    "shedding",
    "express",
    "fastify",
    "http",
    "koa",
    "restify"
  ],
  "author": "David Mark Clements <huperekchuno@googlemail.com>",
  "license": "MIT",
  "devDependencies": {
    "autocannon": "^4.4.1",
    "express": "^4.17.1",
    "koa": "^2.11.0",
    "koa-router": "^7.4.0",
    "pre-commit": "^1.2.2",
    "restify": "^8.5.1",
    "standard": "^10.0.3",
    "tap": "^10.7.2"
  },
  "dependencies": {
    "loopbench": "^1.2.0"
  },
  "directories": {
    "lib": "lib",
    "test": "test"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/davidmarkclements/overload-protection.git"
  },
  "bugs": {
    "url": "https://github.com/davidmarkclements/overload-protection/issues"
  },
  "homepage": "https://github.com/davidmarkclements/overload-protection#readme",
  "description": "Load detection and shedding capabilities for http, express, restify and koa"
}


================================================
FILE: readme.md
================================================
# overload-protection 

Load detection and shedding capabilities for http, express, restify, and koa

[![Build Status](https://travis-ci.org/davidmarkclements/overload-protection.svg?branch=master)](https://travis-ci.org/davidmarkclements/overload-protection)
[![Coverage Status](https://coveralls.io/repos/github/davidmarkclements/overload-protection/badge.svg)](https://coveralls.io/github/davidmarkclements/overload-protection)
[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)


## About

`overload-protection` provides integration for your framework of choice.

If a threshold is crossed for a given metric, `overload-protection` 
will send an HTTP 503 Service Unavailable response, with (by default) 
a `Retry-After` header, instructing the client (e.g. a browser or load balancer) to 
retry after a given amount of seconds.

Current supported metrics are:

* event loop delay (is the JavaScript thread blocking too long)
* Used Heap Memory 
* Total Resident Set Size

For a great explanation of Used Heap Memory vs Resident Set Size see 
Daniel Khans article at <https://www.dynatrace.com/blog/understanding-garbage-collection-and-hunting-memory-leaks-in-node-js>   

## Usage

Create a config object for your thresholds (and other `overload-protection`)
options.

```js
const protectCfg = {
  production: process.env.NODE_ENV === 'production', // if production is false, detailed error messages are exposed to the client
  clientRetrySecs: 1, // Retry-After header, in seconds (0 to disable) [default 1]
  sampleInterval: 5, // sample rate, milliseconds [default 5]
  maxEventLoopDelay: 42, // maximum detected delay between event loop ticks [default 42]
  maxHeapUsedBytes: 0, // maximum heap used threshold (0 to disable) [default 0]
  maxRssBytes: 0, // maximum rss size threshold (0 to disable) [default 0]
  errorPropagationMode: false, // dictate behavior: take over the response 
                              // or propagate an error to the framework [default false]
  logging: false, // set to string for log level or function to pass data to
  logStatsOnReq: false // set to true to log stats on every requests
}
```

Then pass the framework we're integrating with along with the configuration object.

For instance with Express we would do:

```js
const app = require('express')()
const protect = require('overload-protection')('express', protectCfg)
app.use(protect)
```

With middleware based frameworks, always put the `overload-protection` middleware
first. In default mode this means `overload-protection` will take over the response
and prevent any other middleware from executing (thus taking further potential pressure off
of the process).

Restify, and Koa all work in much the same way, call the `overload-protection`
module with the name of the framework, a config object and pass the resulting `protect`
instance to `app.use` – e.g. Koa would be:

```js
const Koa = require('koa')
const protect = require('overload-protection')('koa', protectCfg)
const app = new Koa()
app.use(protect)
```

For pure core HTTP the `overload-protection` instance can be called
at the top of the request handler function. With two arguments (just `req` and `res`)
the function will return `true` if protection/shedding has been provided, or `false`
if not. If `overload-protection` *has* taken over (the `true` case), then we should
exit the function and do no further work:

```js
const http = require('http')
const protect = require('overload-protection')('http', protectCfg)

http.createServer(function (req, res) {
  if (protect(req, res) === true) return
  res.end('content')
})
```

With three arguments (the third argument being a callback), the rest of the 
work should be done within the supplied callback.

```js
const http = require('http')
const protect = require('overload-protection')('http', protectCfg)

http.createServer(function (req, res) {
  protect(req, res, function () {
    // when errorPropagationMode mode is false, will *only* 
    // be called if load shedding didn't occur
    // (if it was true we'd need to check for an Error object as first arg)
    res.end('content')
  })
})
```

## Installation

```sh
npm install overload-protection --save
```

## Tests

```sh
npm install
npm test
```

## Benchmark

The overhead of using `overload-protection` is minimal, run the benchmarks to conduct 
comparative profiling of using `overload-protection` versus not using it for each supported framework.  

```sh
npm run benchmarks
```

## API

### require('overload-protection') => (framework, opts) => instance

The `framework` argument is non-optional. It's a string and may be one of:

* express
* koa
* restify
* http

The `opts` argument is optional, as are all properties.

Options (particularly thresholds) are quite sensitive and highly relevant on 
a case by case basis. Possible options are as follows:

#### production: process.env.NODE_ENV === 'production'

The `production` option determines whether the client receives an error message 
detailing the surpassed threshold(s). (It may also be used in future for other such
good practices or performance trade-offs). 

#### clientRetrySecs: 1

By default, `overload-protection` will add a header to the 503 response
called `Retry-After`. It's up to the client to honour this header, which
instructs the client on how many seconds to wait between retries. 
Defaults to 1 seconds.

#### sampleInterval: 5

In order to establish whether a threshold has been crossed, the metrics 
are sampled at a regular interval. The interval defaults to 5 milliseconds.

####  maxEventLoopDelay: 42

Synchronous work causes the event loop to freeze, when this happens 
an interval timer (which is our sampler) will be delayed by the amount
of time the event loop was stalled for while the thread processed synchronous 
work. We can measure this with timestamp comparison. This option sets a threshold
for the maximum amount of stalling between intervals we'll accept before our
service begins responding with 503 codes to requests. Defaults to 42 milliseconds.

When set to 0 this threshold will be disabled. 

#### maxHeapUsedBytes: 0

Disabled by default (set to 0), this defines maximum V8 (Node's JavaScript engine) used heap size.

If the Used Heap size exceeds the threshold the server will begin return 503 error codes
until it crosses back under the threshold. 

See <https://www.dynatrace.com/blog/understanding-garbage-collection-and-hunting-memory-leaks-in-node-js>
for more info on Used Heap from a V8 context.

#### maxRssBytes: 0

Disabled by default (set to 0) maximum process Resident Set Size. If
the RSS exceeds the threshold the server will begin return 503 error codes
until it crosses back under the threshold.

#### errorPropagationMode: false

**This is relevant to middleware integration only**

By default, `overload-protection` will handle and end the response, 
without calling any subsequent configured middleware. The point here 
is to avoid any further processing for an already (by definition) 
over loaded process.

However, it could be argued, from a puritanical perspective, that middleware
should defer to the framework and that any HTTP code of 500 or above should 
be generated by propagating an error through the framework. 

This option prevents `overload-protection` from manually ended the response and
instead generates an `Error` object (with additional properties as per [`http-errors`](https://github.com/jshttp/http-errors) as used by Express and Koa)     
and propagates it through the framework (either by throwing it in Koa, or passing through the `next` callback).

#### logging: false

The `logging` option can be set to a string or a function. 

If `logging` is set to a string, the string should indicate the desired log 
level for notifying that a 503 response was given. When `logging` is a string
a request bound Log4j-style logger is assumed. This means the `req` object (or the `ctx` object in the case of Koa) 
should have a `log` object which contains methods corresponding to log levels. So if `logging`
was set to `warn` (`logging: 'warn'`) then `req.log.warn` is expected to be present
and be a function. A number of logging libraries follow this pattern, such as 
[`bunyan-express`](http:/npm.im/bunyan-express) and all of the [`pino`](http://npm.im/pino) 
middleware loggers ([`express-pino-logger`](http://npm.im/express), [`koa-pino-logger`](http://npm.im/koa-pino-logger), 
[`restify-pino-logger`](http://npm.im/restify-pino-logger), [`pino-http`](http://npm.im/pino-http)).

If the application isn't using a request bound Log4j-style logger, the `logging` 
option can be set to a function which receives a log message. This function is 
then responsible for writing the log. We could also simply set it to one of
the console methods, e.g. `logging: console.warn`. 

This is primarily for usage when `errorPropagationMode` is `false`. If `errorPropagationMode` 
is set to `true`, we may want to instead log once the error has propagated to a handler.    

#### logStatsOnReq: false

Set `logStatsOnReq` to `true` log the profiled stats on every request. In order to use this option, the `logging` option must not be `false`. Bear in mind that using this option will
add extra pressure on the event loop in itself, so use with caution.

### instance.overload

The returned instance (which in many cases is passed as middleware to `app.use`), 
has an `overload` property. This begins as `false`. If any of the thresholds have 
been passed this will be set to `true`. Once all metrics are below their thresholds
this would become `false` again.

This allows for any heavy load detection required outside of a framework. 

### instance.eventLoopOverload

The returned instance (which in many cases is passed as middleware to `app.use`), 
has an `eventLoopOverload` property. This begins as `false`. If the `maxEventLoopDelay`
threshold is passed this will be set to `true`. Once it's below the configured threshold
this would become `false` again.

This allows for any event loop delay detection necessary outside of a framework.

### instance.heapUsedOverload

The returned instance (which in many cases is passed as middleware to `app.use`), 
has a `heapUsedOverload` property. This begins as `false`. If the `maxHeapUsedBytes`
threshold is passed this will be set to `true`. Once it's below the configured threshold
this would become `false` again.

This allows for any heap used threshold detection necessary outside of a framework.

### instance.rssOverload

The returned instance (which in many cases is passed as middleware to `app.use`), 
has a `rssOverload` property. This begins as `false`. If the `maxRssBytes`
threshold is passed this will be set to `true`. Once it's below the configured threshold
this would become `false` again.

This allows for any heap used threshold detection necessary outside of a framework.

### instance.eventLoopDelay

The delay in milliseconds (with additional decimal precision) since the last sample.

If `maxEventLoopDelay` is 0, the event loop is not measured, so `eventLoopDelay` will always
be 0 in that case.

### instance.maxEventLoopDelay

Corresponds to the `opts.maxEventLoopDelay` option.

### instance.maxHeapUsedBytes

Corresponds to the `opts.maxHeapUsedBytes` option.

### instance.maxRssBytes

Corresponds to the `opts.maxRssBytes` option.

## Dependencies

- [loopbench](https://github.com/mcollina/loopbench): Benchmark your event loop

## Dev Dependencies

- [autocannon](https://github.com/mcollina/autocannon): Fast HTTP benchmarking tool written in Node.js
- [express](https://github.com/expressjs/express): Fast, unopinionated, minimalist web framework
- [koa](https://github.com/koajs/koa): Koa web app framework
- [koa-router](https://github.com/alexmingoia/koa-router): Router middleware for koa. Provides RESTful resource routing.
- [pre-commit](https://github.com/observing/pre-commit): Automatically install pre-commit hooks for your npm modules.
- [restify](https://github.com/restify/node-restify): REST framework
- [standard](https://github.com/standard/standard): JavaScript Standard Style
- [tap](https://github.com/tapjs/node-tap): A Test-Anything-Protocol library

## License

MIT

## Acknowledgements

Kindly sponsored by [nearForm](http://nearform.com)


================================================
FILE: test/index.js
================================================
'use strict'
var test = require('tap').test
var protect = require('../')

test('throws if framework is unspecified', function (t) {
  t.throws(function () {
    protect()
  })
  t.end()
})

test('throws if framework is not supported', function (t) {
  t.throws(function () {
    protect('not a thing')
  })
  t.end()
})

test('throws if all thresholds are disabled (set to 0)', function (t) {
  t.throws(function () {
    protect('http', {
      eventLoopDelay: 0,
      maxRssBytes: 0,
      maxHeapUsedBytes: 0
    })
  })
  t.end()
})

test('throws if logStatsOnReq is true but logging is false', function (t) {
  t.throws(function () {
    protect('http', {
      logStatsOnReq: true
    })
  })
  t.end()
})

test('instance.stop ceases sampling', function (t) {
  var sI = global.setInterval
  var cI = global.clearInterval
  var mock = {unref: function () { return mock }}
  global.setInterval = function () { return mock }
  global.clearInterval = function (ref) {
    t.is(ref, mock)
    global.setInterval = sI
    global.clearInterval = cI
    t.end()
  }
  var instance = protect('http')
  instance.stop()
})

test('sampleInterval option sets the sample rate', function (t) {
  var sI = global.setInterval
  var cI = global.clearInterval
  var sampleRate = 88
  var mock = {unref: function () { return mock }}
  global.setInterval = function (fn, n) {
    t.is(n, sampleRate)
    return mock
  }
  global.clearInterval = function (ref) {
    t.is(ref, mock)
    global.setInterval = sI
    global.clearInterval = cI
    t.end()
  }
  var instance = protect('http', {
    sampleInterval: sampleRate
  })
  instance.stop()
})

test('exposes maxEventLoopDelay option on instance', function (t) {
  var value = 9999
  var instance = protect('http', {
    maxEventLoopDelay: value
  })
  t.is(instance.maxEventLoopDelay, value)
  instance.stop()
  t.end()
})

test('exposes maxHeapUsedBytes option on instance', function (t) {
  var value = 9999
  var instance = protect('http', {
    maxHeapUsedBytes: value
  })
  t.is(instance.maxHeapUsedBytes, value)
  instance.stop()
  t.end()
})

test('exposes maxRssBytes option on instance', function (t) {
  var value = 9999
  var instance = protect('http', {
    maxRssBytes: value
  })
  t.is(instance.maxRssBytes, value)
  instance.stop()
  t.end()
})

test('instance.eventLoopDelay indicates the delay between samples', function (t) {
  var delay = 50
  var instance = protect('http')
  var start = Date.now()
  // "sleep" with while blocking is imprecise, particularly in turbofan,
  // throwing in a Buffer.alloc to compensate
  while (Date.now() - start <= delay) { Buffer.alloc(1e9) }
  setImmediate(function () {
    t.is(instance.eventLoopDelay > delay, true)
    instance.stop()
    t.end()
  })
})

test('instance.eventLoopOverload is true when maxEventLoopDelay threshold is breached', function (t) {
  var delay = 50
  var instance = protect('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 10
  })
  var start = Date.now()
  while (Date.now() - start < delay) {}
  setImmediate(function () {
    t.is(instance.eventLoopOverload, true)
    instance.stop()
    t.end()
  })
})

test('instance.eventLoopOverload is false when returning under maxEventLoopDelay threshold', function (t) {
  var delay = 50
  var instance = protect('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 10
  })
  var start = Date.now()
  while (Date.now() - start < delay) {}
  setImmediate(function () {
    setTimeout(function () {
      t.is(instance.eventLoopOverload, false)
      instance.stop()
      t.end()
    }, 10)
  })
})

test('instance.eventLoopOverload is always false when maxEventLoopDelay is 0 (maxHeapUsedBytes enabled)', function (t) {
  var delay = 50
  var instance = protect('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxHeapUsedBytes: 10
  })
  var start = Date.now()
  while (Date.now() - start < delay) {}
  setImmediate(function () {
    t.is(instance.eventLoopOverload, false)
    instance.stop()
    t.end()
  })
})

test('instance.eventLoopOverload is always false when maxEventLoopDelay is 0 (maxRssBytes enabled)', function (t) {
  var delay = 50
  var instance = protect('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 10
  })
  var start = Date.now()
  while (Date.now() - start < delay) {}
  setImmediate(function () {
    t.is(instance.eventLoopOverload, false)
    instance.stop()
    t.end()
  })
})

test('instance.overload is true if instance.eventLoopOverload is true', function (t) {
  var delay = 50
  var instance = protect('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 1
  })
  var start = Date.now()
  while (Date.now() - start < delay) {}
  setImmediate(function () {
    t.is(instance.eventLoopOverload, true)
    t.is(instance.overload, instance.eventLoopOverload)
    instance.stop()
    t.end()
  })
})

test('instance.heapUsedOverload is true when maxHeapUsedBytes threshold is breached', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxHeapUsedBytes: 10
  })
  setTimeout(function () {
    t.is(instance.heapUsedOverload, true)
    process.memoryUsage = memoryUsage
    instance.stop()
    t.end()
  }, 6)
})

test('instance.heapUsedOverload is false when returning under maxHeapUsedBytes threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxHeapUsedBytes: 10
  })
  setTimeout(function () {
    process.memoryUsage = function () {
      return {
        rss: 99999,
        heapTotal: 9999,
        heapUsed: 2,
        external: 99
      }
    }
    setTimeout(function () {
      t.is(instance.heapUsedOverload, false)
      process.memoryUsage = memoryUsage
      instance.stop()
      t.end()
    }, 6)
  }, 6)
})

test('instance.heapUsedOverload is always false when maxHeapUsedBytes is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxHeapUsedBytes: 0
  })
  setTimeout(function () {
    t.is(instance.heapUsedOverload, false)
    process.memoryUsage = memoryUsage
    instance.stop()
    t.end()
  }, 6)
})

test('instance.overload is true if instance.heapUsedOverload is true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxHeapUsedBytes: 10
  })
  setTimeout(function () {
    t.is(instance.heapUsedOverload, true)
    t.is(instance.overload, instance.heapUsedOverload)
    instance.stop()
    process.memoryUsage = memoryUsage
    t.end()
  }, 6)
})

test('instance.rssOverload is true when maxRssBytes threshold is breached', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxRssBytes: 10
  })
  setTimeout(function () {
    t.is(instance.rssOverload, true)
    process.memoryUsage = memoryUsage
    instance.stop()
    t.end()
  }, 6)
})

test('instance.rssOverload is false when returning under maxRssBytes threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxHeapUsedBytes: 10
  })
  setTimeout(function () {
    process.memoryUsage = function () {
      return {
        rss: 2,
        heapTotal: 9999,
        heapUsed: 2,
        external: 99
      }
    }
    setTimeout(function () {
      t.is(instance.rssOverload, false)
      instance.stop()
      process.memoryUsage = memoryUsage
      t.end()
    }, 6)
  }, 6)
})

test('instance.rssOverload is always false when maxRssBytes is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxRssBytes: 0
  })
  setTimeout(function () {
    t.is(instance.rssOverload, false)
    instance.stop()
    process.memoryUsage = memoryUsage
    t.end()
  }, 6)
})

test('instance.overload is true if instance.rssOverload is true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var instance = protect('http', {
    sampleInterval: 5,
    maxRssBytes: 10
  })
  setTimeout(function () {
    t.is(instance.rssOverload, true)
    t.is(instance.overload, instance.rssOverload)
    instance.stop()
    process.memoryUsage = memoryUsage
    t.end()
  }, 6)
})

if (Object.setPrototypeOf) {
  test('Supports legacy JS (__proto__)', function (t) {
    var setPrototypeOf = Object.setPrototypeOf
    delete Object.setPrototypeOf
    var instance = protect('http')
    // overload wouldn't be in instance if __proto__ wasn't set
    t.is('overload' in instance, true)
    t.end()
    Object.setPrototypeOf = setPrototypeOf
  })
}

if (!Object.setPrototypeOf) {
  test('Supports modern/future JS (Object.setPrototypeOf)', function (t) {
    Object.setPrototypeOf = function (o, proto) {
      o.__proto__ = proto // eslint-disable-line
    }
    var instance = protect('http')
    // overload wouldn't be in instance if __proto__ wasn't set
    t.is('overload' in instance, true)
    t.end()
    delete Object.setPrototypeOf
  })
}


================================================
FILE: test/integration/express/index.js
================================================
'use strict'

var http = require('http')
var express = require('express')

var protection = require('../../..')
var test = require('tap').test

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}

test('sends 503 when event loop is overloaded, per maxEventLoopDelay', function (t) {
  var protect = protection('express', {
    maxEventLoopDelay: 1
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(function (req, res) {
    sleep(500)
    app(req, res)
  })

  server.listen(3000, function () {
    var req = http.get('http://localhost:3000')
    req.on('response', function (res) {
      t.is(res.statusCode, 503)
      protect.stop()
      server.close()
      t.end()
    }).end()
  })
})

test('sends 503 when heap used threshold is passed, as per maxHeapUsedBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxHeapUsedBytes: 40
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends 503 when heap used threshold is passed, as per maxRssBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends Retry-After header as per clientRetrySecs', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 22
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is(res.headers['retry-after'], '22')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('does not set Retry-After header when clientRetrySecs is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 0
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is('retry-after' in res.headers, false)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:false (default)', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = express()
  app.use(protect)
  app.use(function () {
    t.fail()
  })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = express()
  app.use(protect)
  app.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.statusCode, 503)
    res.end('err message')
  })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in default mode, production:false leads to high detail client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Server experiencing heavy load: (rss)')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in default mode, production:true leads to standard 503 client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = express()
  app.use(protect)
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Service Unavailable')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:false sets expose:true on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = express()
  app.use(protect)
  app.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.expose, true)
    res.end('err message')
  })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:true sets expose:false on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = express()
  app.use(protect)
  app.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.expose, false)
    res.end('err message')
  })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('resumes usual operation once load pressure is reduced under threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var app = express()
  app.use(protect)
  app.get('/', function (req, res) { res.end('content') })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        process.memoryUsage = function () {
          return {
            rss: 10,
            heapTotal: 9999,
            heapUsed: 999,
            external: 99
          }
        }
        setTimeout(function () {
          http.get('http://localhost:3000').on('response', function (res) {
            t.is(res.statusCode, 200)
            server.close()
            protect.stop()
            process.memoryUsage = memoryUsage
            t.end()
          })
        }, 6)
      }).end()
    }, 6)
  })
})

test('if logging option is a string, when overloaded, writes log message using req.log as per level in string', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: 'warn'
  })

  var app = express()
  app.use(function (req, res, next) {
    req.log = {
      warn: function (msg) {
        t.is(msg, 'Server experiencing heavy load: (rss)')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }
    }
    next()
  })
  app.use(protect)
  app.get('/', function (req, res) { res.end('content') })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logging option is a function, when overloaded calls the function with heavy load message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('express', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: function (msg) {
      t.is(msg, 'Server experiencing heavy load: (rss)')
      server.close()
      protect.stop()
      process.memoryUsage = memoryUsage
      t.end()
    }
  })

  var app = express()
  app.use(protect)
  app.get('/', function (req, res) { res.end('content') })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and if logging option is a string, writes log message using req.log as per level in string for every request', function (t) {
  var protect = protection('express', {
    logging: 'info',
    logStatsOnReq: true
  })
  t.plan(1)
  var app = express()
  app.use(function (req, res, next) {
    req.log = {
      info: function (msg) {
        t.same(Object.keys(msg), [
          'overload',
          'eventLoopOverload',
          'heapUsedOverload',
          'rssOverload',
          'eventLoopDelay',
          'maxEventLoopDelay',
          'maxHeapUsedBytes',
          'maxRssBytes'
        ])
        server.close()
        protect.stop()
        t.end()
      }
    }
    next()
  })
  app.use(protect)
  app.get('/', function (req, res) { res.end('content') })
  var server = http.createServer(app)

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and logging option is a function, calls the function with stats on every request', function (t) {
  var protect = protection('express', {
    logStatsOnReq: true,
    logging: function (msg) {
      t.same(Object.keys(msg), [
        'overload',
        'eventLoopOverload',
        'heapUsedOverload',
        'rssOverload',
        'eventLoopDelay',
        'maxEventLoopDelay',
        'maxHeapUsedBytes',
        'maxRssBytes'
      ])
      server.close()
      protect.stop()
      t.end()
    }
  })

  var app = express()
  app.use(protect)
  app.get('/', function (req, res) { res.end('content') })
  var server = http.createServer(app)

  server.listen(3001, function () {
    setTimeout(function () {
      http.get('http://localhost:3001').end()
    }, 6)
  })
})


================================================
FILE: test/integration/http/index.js
================================================
'use strict'

var http = require('http')

var protection = require('../../..')
var test = require('tap').test

function sleep (msec) {
  var start = Date.now()
  while (Date.now() - start < msec) {}
}

test('sends 503 when event loop is overloaded, per maxEventLoopDelay', function (t) {
  var protect = protection('http', {
    maxEventLoopDelay: 1
  })

  var server = http.createServer(function serve (req, res) {
    sleep(500)
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    var req = http.get('http://localhost:3000')
    req.on('response', function (res) {
      t.is(res.statusCode, 503)
      protect.stop()
      server.close()
      t.end()
    }).end()
  })
})

test('sends 503 when heap used threshold is passed, as per maxHeapUsedBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxHeapUsedBytes: 40
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends 503 when heap used threshold is passed, as per maxRssBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends Retry-After header as per clientRetrySecs', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 22
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is(res.headers['retry-after'], '22')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('does not set Retry-After header when clientRetrySecs is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 0
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is('retry-after' in res.headers, false)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('callback api with errorPropagationMode false (default)', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = http.createServer(function serve (req, res) {
    protect(req, res, function () {
      t.fail() // should never be called
      res.end('content')
    })
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('callback api with errorPropagationMode true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = http.createServer(function serve (req, res) {
    protect(req, res, function (err) {
      t.ok(err)
      t.is(err.statusCode, 503)
      res.end('err message')
    })
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in default mode, production:false leads to high detail client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Server experiencing heavy load: (rss)')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in default mode, production:true leads to standard 503 client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Service Unavailable')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:false sets expose:true on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = http.createServer(function serve (req, res) {
    protect(req, res, function (err) {
      t.ok(err)
      t.is(err.expose, true)
      res.end('err message')
    })
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:true sets expose:false on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = http.createServer(function serve (req, res) {
    protect(req, res, function (err) {
      t.ok(err)
      t.is(err.expose, false)
      res.end('err message')
    })
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('resumes usual operation once load pressure is reduced under threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        process.memoryUsage = function () {
          return {
            rss: 10,
            heapTotal: 9999,
            heapUsed: 999,
            external: 99
          }
        }
        setTimeout(function () {
          http.get('http://localhost:3000').on('response', function (res) {
            t.is(res.statusCode, 200)
            server.close()
            protect.stop()
            process.memoryUsage = memoryUsage
            t.end()
          })
        }, 6)
      }).end()
    }, 6)
  })
})

test('(callback api) resumes usual operation once load pressure is reduced under threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var server = http.createServer(function serve (req, res) {
    protect(req, res, function () {
      res.end('content')
    })
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        process.memoryUsage = function () {
          return {
            rss: 10,
            heapTotal: 9999,
            heapUsed: 999,
            external: 99
          }
        }
        setTimeout(function () {
          http.get('http://localhost:3000').on('response', function (res) {
            t.is(res.statusCode, 200)
            server.close()
            protect.stop()
            process.memoryUsage = memoryUsage
            t.end()
          })
        }, 6)
      }).end()
    }, 6)
  })
})

test('if logging option is a string, when overloaded, writes log message using req.log as per level in string', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 1,
    maxRssBytes: 40,
    maxHeapUsedBytes: 40,
    logging: 'warn'
  })

  var server = http.createServer(function serve (req, res) {
    req = {
      log: {
        warn: function (msg) {
          t.is(msg, 'Server experiencing heavy load: (event loop, heap, rss)')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        }
      }
    }
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      sleep(500)
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logging option is a function, when overloaded calls the function with heavy load message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('http', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: function (msg) {
      t.is(msg, 'Server experiencing heavy load: (rss)')
      server.close()
      protect.stop()
      process.memoryUsage = memoryUsage
      t.end()
    }
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and if logging option is a string, writes log message using req.log as per level in string for every request', function (t) {
  var protect = protection('http', {
    logging: 'info',
    logStatsOnReq: true
  })
  t.plan(1)
  var server = http.createServer(function serve (req, res) {
    req = {
      log: {
        info: function (msg) {
          t.same(Object.keys(msg), [
            'overload',
            'eventLoopOverload',
            'heapUsedOverload',
            'rssOverload',
            'eventLoopDelay',
            'maxEventLoopDelay',
            'maxHeapUsedBytes',
            'maxRssBytes'
          ])
          server.close()
          protect.stop()
          t.end()
        }
      }
    }
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and logging option is a function, calls the function with stats on every request', function (t) {
  var protect = protection('http', {
    logStatsOnReq: true,
    logging: function (msg) {
      t.same(Object.keys(msg), [
        'overload',
        'eventLoopOverload',
        'heapUsedOverload',
        'rssOverload',
        'eventLoopDelay',
        'maxEventLoopDelay',
        'maxHeapUsedBytes',
        'maxRssBytes'
      ])
      server.close()
      protect.stop()
      t.end()
    }
  })

  var server = http.createServer(function serve (req, res) {
    if (protect(req, res) === true) return
    res.end('content')
  })

  server.listen(3002, function () {
    setTimeout(function () {
      http.get('http://localhost:3002').end()
    }, 6)
  })
})


================================================
FILE: test/integration/koa/index.js
================================================
'use strict'
var http = require('http')
var Koa = require('koa')
var Router = require('koa-router')
var protection = require('../../..')
var test = require('tap').test

function block (n) {
  while (n--) { JSON.parse(JSON.stringify(require('../../../package.json'))) }
}

test('sends 503 when event loop is overloaded, per maxEventLoopDelay', function (t) {
  var protect = protection('koa', {
    maxEventLoopDelay: 1
  })

  var app = new Koa()

  app.use(protect)

  var server = app.listen(3000, function () {
    var req = http.get('http://localhost:3000')
    block(50000)
    req.on('response', function (res) {
      t.is(res.statusCode, 503)
      protect.stop()
      server.close()
      t.end()
    }).end()
  })
})

test('sends 503 when heap used threshold is passed, as per maxHeapUsedBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxHeapUsedBytes: 40
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends 503 when rss threshold is passed, as per maxRssBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends Retry-After header as per clientRetrySecs', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 22
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is(res.headers['retry-after'], '22')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('does not set Retry-After header when clientRetrySecs is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 0
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is('retry-after' in res.headers, false)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:false (default)', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = new Koa()
  app.use(protect)
  app.use(function (ctx, next) {
    t.fail()
    return next()
  })

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = new Koa()
  app.on('error', function () {}) // silence error log output
  app.use(function (ctx, next) {
    return next().catch(function (err) {
      t.ok(err)
      t.is(err.status, 503)
      throw err
    })
  })

  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in default mode, production:false leads to high detail client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Server experiencing heavy load: (rss)')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in default mode, production:true leads to standard 503 client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Service Unavailable')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:false sets expose:true on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = new Koa()
  app.on('error', function () {}) // silence error log output
  app.use(function (ctx, next) {
    return next().catch(function (err) {
      t.ok(err)
      t.is(err.expose, true)
      throw err
    })
  })

  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:true sets expose:false on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var app = new Koa()
  app.on('error', function () {}) // silence error log output
  app.use(function (ctx, next) {
    return next().catch(function (err) {
      t.ok(err)
      t.is(err.expose, false)
      throw err
    })
  })
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('resumes usual operation once load pressure is reduced under threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var app = new Koa()
  var router = new Router()
  app.use(protect)
  router.get('/', function (ctx, next) {
    ctx.body = 'content'
    return next()
  })

  app.use(router.routes())

  var server = app.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        process.memoryUsage = function () {
          return {
            rss: 10,
            heapTotal: 9999,
            heapUsed: 999,
            external: 99
          }
        }
        setTimeout(function () {
          http.get('http://localhost:3000').on('response', function (res) {
            t.is(res.statusCode, 200)
            server.close()
            protect.stop()
            process.memoryUsage = memoryUsage
            t.end()
          })
        }, 6)
      }).end()
    }, 6)
  })
})

test('if logging option is a string, when overloaded, writes log message using req.log as per level in string', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: 'warn'
  })

  var app = new Koa()
  app.use(function (ctx, next) {
    ctx.log = ctx.req.log = {
      warn: function (msg) {
        t.is(msg, 'Server experiencing heavy load: (rss)')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }
    }
    return next()
  })
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logging option is a function, when overloaded calls the function with heavy load message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('koa', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: function (msg) {
      t.is(msg, 'Server experiencing heavy load: (rss)')
      server.close()
      protect.stop()
      process.memoryUsage = memoryUsage
      t.end()
    }
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and if logging option is a string, writes log message using req.log as per level in string for every request', function (t) {
  var protect = protection('koa', {
    logging: 'info',
    logStatsOnReq: true
  })
  t.plan(1)
  var app = new Koa()
  app.use(function (ctx, next) {
    ctx.log = ctx.req.log = {
      info: function (msg) {
        t.same(Object.keys(msg), [
          'overload',
          'eventLoopOverload',
          'heapUsedOverload',
          'rssOverload',
          'eventLoopDelay',
          'maxEventLoopDelay',
          'maxHeapUsedBytes',
          'maxRssBytes'
        ])
        server.close()
        protect.stop()
        t.end()
      }
    }
    return next()
  })
  app.use(protect)

  var server = app.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and logging option is a function, calls the function with stats on every request', function (t) {
  var protect = protection('koa', {
    logStatsOnReq: true,
    logging: function (msg) {
      t.same(Object.keys(msg), [
        'overload',
        'eventLoopOverload',
        'heapUsedOverload',
        'rssOverload',
        'eventLoopDelay',
        'maxEventLoopDelay',
        'maxHeapUsedBytes',
        'maxRssBytes'
      ])
      server.close()
      protect.stop()
      t.end()
    }
  })

  var app = new Koa()
  app.use(protect)

  var server = app.listen(3001, function () {
    setTimeout(function () {
      http.get('http://localhost:3001').end()
    }, 6)
  })
})


================================================
FILE: test/integration/restify/index.js
================================================
'use strict'

var http = require('http')
var restify = require('restify')

var protection = require('../../..')
var test = require('tap').test

function block (n) {
  while (n--) { JSON.parse(JSON.stringify(require('../../../package.json'))) }
}

test('sends 503 when event loop is overloaded, per maxEventLoopDelay', function (t) {
  var protect = protection('restify', {
    maxEventLoopDelay: 1
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    var req = http.get('http://localhost:3000')
    block(50000)
    req.on('response', function (res) {
      t.is(res.statusCode, 503)
      protect.stop()
      server.close()
      t.end()
    }).end()
  })
})

test('sends 503 when heap used threshold is passed, as per maxHeapUsedBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxHeapUsedBytes: 40
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends 503 when heap used threshold is passed, as per maxRssBytes', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('sends Retry-After header as per clientRetrySecs', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 22
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is(res.headers['retry-after'], '22')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('does not set Retry-After header when clientRetrySecs is 0', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    clientRetrySecs: 0
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        t.is('retry-after' in res.headers, false)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:false (default)', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })
  server.use(function () {
    t.fail()
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('errorPropagationMode:true', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })
  server.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.statusCode, 503)
    res.end('err message')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in default mode, production:false leads to high detail client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Server experiencing heavy load: (rss)')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in default mode, production:true leads to standard 503 client response message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: false
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        res.once('data', function (msg) {
          msg = msg.toString()
          t.is(msg, 'Service Unavailable')
          server.close()
          protect.stop()
          process.memoryUsage = memoryUsage
          t.end()
        })
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:false sets expose:true on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    production: false,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })
  server.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.expose, true)
    res.end('err message')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('in errorPropagationMode production:true sets expose:false on error object', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    production: true,
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    errorPropagationMode: true
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })
  server.use(function (err, req, res, next) {
    t.ok(err)
    t.is(err.expose, false)
    res.end('err message')
  })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }).end()
    }, 6)
  })
})

test('resumes usual operation once load pressure is reduced under threshold', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      var req = http.get('http://localhost:3000')
      req.on('response', function (res) {
        t.is(res.statusCode, 503)
        process.memoryUsage = function () {
          return {
            rss: 10,
            heapTotal: 9999,
            heapUsed: 999,
            external: 99
          }
        }
        setTimeout(function () {
          http.get('http://localhost:3000').on('response', function (res) {
            t.is(res.statusCode, 200)
            server.close()
            protect.stop()
            process.memoryUsage = memoryUsage
            t.end()
          })
        }, 6)
      }).end()
    }, 6)
  })
})

test('if logging option is a string, when overloaded, writes log message using req.log as per level in string', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: 'warn'
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(function (req, res, next) {
    req.log = {
      warn: function (msg) {
        t.is(msg, 'Server experiencing heavy load: (rss)')
        server.close()
        protect.stop()
        process.memoryUsage = memoryUsage
        t.end()
      }
    }
    next()
  })
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logging option is a function, when overloaded calls the function with heavy load message', function (t) {
  var memoryUsage = process.memoryUsage
  process.memoryUsage = function () {
    return {
      rss: 99999,
      heapTotal: 9999,
      heapUsed: 999,
      external: 99
    }
  }
  var protect = protection('restify', {
    sampleInterval: 5,
    maxEventLoopDelay: 0,
    maxRssBytes: 40,
    logging: function (msg) {
      t.is(msg, 'Server experiencing heavy load: (rss)')
      server.close()
      protect.stop()
      process.memoryUsage = memoryUsage
      t.end()
    }
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and if logging option is a string, writes log message using req.log as per level in string for every request', function (t) {
  var protect = protection('restify', {
    logging: 'info',
    logStatsOnReq: true
  })
  t.plan(1)
  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(function (req, res, next) {
    req.log = {
      info: function (msg) {
        t.same(Object.keys(msg), [
          'overload',
          'eventLoopOverload',
          'heapUsedOverload',
          'rssOverload',
          'eventLoopDelay',
          'maxEventLoopDelay',
          'maxHeapUsedBytes',
          'maxRssBytes'
        ])
        server.close()
        protect.stop()
        t.end()
      }
    }
    next()
  })
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })
  server.listen(3000, function () {
    setTimeout(function () {
      http.get('http://localhost:3000').end()
    }, 6)
  })
})

test('if logStatsOnReq is true and logging option is a function, calls the function with stats on every request', function (t) {
  var protect = protection('restify', {
    logStatsOnReq: true,
    logging: function (msg) {
      t.same(Object.keys(msg), [
        'overload',
        'eventLoopOverload',
        'heapUsedOverload',
        'rssOverload',
        'eventLoopDelay',
        'maxEventLoopDelay',
        'maxHeapUsedBytes',
        'maxRssBytes'
      ])
      server.close()
      protect.stop()
      t.end()
    }
  })

  var server = restify.createServer({name: 'myapp', version: '1.0.0'})
  server.use(protect)
  server.get('/', function (req, res) { res.end('content') })

  server.listen(3001, function () {
    setTimeout(function () {
      http.get('http://localhost:3001').end()
    }, 6)
  })
})