agentkeepalive

What is agentkeepalive?

The agentkeepalive npm package is a module that provides an HTTP(S) Agent which keeps socket connections alive between keep-alive requests. It is designed to improve the performance of HTTP clients by reusing sockets for subsequent requests to the same servers, which can reduce the overhead of establishing new TCP connections.

What are agentkeepalive's main functionalities?

HTTP Keep-Alive Agent

This feature allows you to create an HTTP agent that reuses sockets for HTTP requests to improve performance.

const { HttpAgent } = require('agentkeepalive');
const keepaliveAgent = new HttpAgent();
const http = require('http');

http.request({
  host: 'localhost',
  port: 80,
  path: '/',
  agent: keepaliveAgent
});

HTTPS Keep-Alive Agent

This feature allows you to create an HTTPS agent that reuses sockets for HTTPS requests to improve performance.

const { HttpsAgent } = require('agentkeepalive').HttpsAgent;
const keepaliveAgent = new HttpsAgent();
const https = require('https');

https.request({
  host: 'localhost',
  port: 443,
  path: '/',
  agent: keepaliveAgent
});

Custom Agent Options

This feature allows you to customize the behavior of the keep-alive agent by setting options such as the maximum number of sockets, the maximum number of free sockets, socket timeout, and free socket timeout.

const { HttpAgent } = require('agentkeepalive');
const keepaliveAgent = new HttpAgent({
  maxSockets: 50,
  maxFreeSockets: 10,
  timeout: 60000,
  freeSocketTimeout: 30000
});

Other packages similar to agentkeepalive

forever-agent

forever-agent is similar to agentkeepalive in that it provides an HTTP(S) agent that keeps connections alive indefinitely. It is less configurable than agentkeepalive and does not provide the same level of control over socket reuse and timeouts.

README

agentkeepalive

The enhancement features keep alive http.Agent. Support http and https.

What's different from original http.Agent?

• keepAlive=true by default
• Disable Nagle's algorithm: socket.setNoDelay(true)
• Add free socket timeout: avoid long time inactivity socket leak in the free-sockets queue.
• Add active socket timeout: avoid long time inactivity socket leak in the active-sockets queue.
• TTL for active socket.

Node.js version required

Support Node.js >= 8.0.0

Install

$ npm install agentkeepalive --save

new Agent([options])

• options {Object} Set of configurable options to set on the agent. Can have the following fields:
  • keepAlive {Boolean} Keep sockets around in a pool to be used by other requests in the future. Default = true.
  • keepAliveMsecs {Number} When using the keepAlive option, specifies the initial delay for TCP Keep-Alive packets. Ignored when the keepAlive option is false or undefined. Defaults to 1000. Default = 1000. Only relevant if keepAlive is set to true.
  • freeSocketTimeout: {Number} Sets the free socket to timeout after freeSocketTimeout milliseconds of inactivity on the free socket. The default server-side timeout is 5000 milliseconds, to avoid ECONNRESET exceptions, we set the default value to 4000 milliseconds. Only relevant if keepAlive is set to true.
  • timeout: {Number} Sets the working socket to timeout after timeout milliseconds of inactivity on the working socket. Default is freeSocketTimeout * 2 so long as that value is greater than or equal to 8 seconds, otherwise the default is 8 seconds.
  • maxSockets {Number} Maximum number of sockets to allow per host. Default = Infinity.
  • maxFreeSockets {Number} Maximum number of sockets (per host) to leave open in a free state. Only relevant if keepAlive is set to true. Default = 256.
  • socketActiveTTL {Number} Sets the socket active time to live, even if it's in use. If not set, the behaviour keeps the same (the socket will be released only when free) Default = null.

Usage

const http = require('http');
const Agent = require('agentkeepalive');

const keepaliveAgent = new Agent({
  maxSockets: 100,
  maxFreeSockets: 10,
  timeout: 60000, // active socket keepalive for 60 seconds
  freeSocketTimeout: 30000, // free socket keepalive for 30 seconds
});

const options = {
  host: 'cnodejs.org',
  port: 80,
  path: '/',
  method: 'GET',
  agent: keepaliveAgent,
};

const req = http.request(options, res => {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));
  res.setEncoding('utf8');
  res.on('data', function (chunk) {
    console.log('BODY: ' + chunk);
  });
});
req.on('error', e => {
  console.log('problem with request: ' + e.message);
});
req.end();

setTimeout(() => {
  if (keepaliveAgent.statusChanged) {
    console.log('[%s] agent status changed: %j', Date(), keepaliveAgent.getCurrentStatus());
  }
}, 2000);

getter agent.statusChanged

counters have change or not after last checkpoint.

agent.getCurrentStatus()

agent.getCurrentStatus() will return a object to show the status of this agent:

{
  createSocketCount: 10,
  closeSocketCount: 5,
  timeoutSocketCount: 0,
  requestCount: 5,
  freeSockets: { 'localhost:57479:': 3 },
  sockets: { 'localhost:57479:': 5 },
  requests: {}
}

Support https

const https = require('https');
const HttpsAgent = require('agentkeepalive').HttpsAgent;

const keepaliveAgent = new HttpsAgent();
// https://www.google.com/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
const options = {
  host: 'www.google.com',
  port: 443,
  path: '/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8',
  method: 'GET',
  agent: keepaliveAgent,
};

const req = https.request(options, res => {
  console.log('STATUS: ' + res.statusCode);
  console.log('HEADERS: ' + JSON.stringify(res.headers));
  res.setEncoding('utf8');
  res.on('data', chunk => {
    console.log('BODY: ' + chunk);
  });
});

req.on('error', e => {
  console.log('problem with request: ' + e.message);
});
req.end();

setTimeout(() => {
  console.log('agent status: %j', keepaliveAgent.getCurrentStatus());
}, 2000);

Support req.reusedSocket

This agent implements the req.reusedSocket to determine whether a request is send through a reused socket.

When server closes connection at unfortunate time (keep-alive race), the http client will throw a ECONNRESET error. Under this circumstance, req.reusedSocket is useful when we want to retry the request automatically.

const http = require('http');
const Agent = require('agentkeepalive');
const agent = new Agent();

const req = http
  .get('http://localhost:3000', { agent }, (res) => {
    // ...
  })
  .on('error', (err) => {
    if (req.reusedSocket && err.code === 'ECONNRESET') {
      // retry the request or anything else...
    }
  })

This behavior is consistent with Node.js core. But through agentkeepalive, you can use this feature in older Node.js version.

Benchmark

run the benchmark:

cd benchmark
sh start.sh

Intel(R) Core(TM)2 Duo CPU P8600 @ 2.40GHz

node@v0.8.9

50 maxSockets, 60 concurrent, 1000 requests per concurrent, 5ms delay

Keep alive agent (30 seconds):

Transactions:          60000 hits
Availability:         100.00 %
Elapsed time:          29.70 secs
Data transferred:        14.88 MB
Response time:            0.03 secs
Transaction rate:      2020.20 trans/sec
Throughput:           0.50 MB/sec
Concurrency:           59.84
Successful transactions:       60000
Failed transactions:             0
Longest transaction:          0.15
Shortest transaction:         0.01

Normal agent:

Transactions:          60000 hits
Availability:         100.00 %
Elapsed time:          46.53 secs
Data transferred:        14.88 MB
Response time:            0.05 secs
Transaction rate:      1289.49 trans/sec
Throughput:           0.32 MB/sec
Concurrency:           59.81
Successful transactions:       60000
Failed transactions:             0
Longest transaction:          0.45
Shortest transaction:         0.00

Socket created:

[proxy.js:120000] keepalive, 50 created, 60000 requestFinished, 1200 req/socket, 0 requests, 0 sockets, 0 unusedSockets, 50 timeout
{" <10ms":662," <15ms":17825," <20ms":20552," <30ms":17646," <40ms":2315," <50ms":567," <100ms":377," <150ms":56," <200ms":0," >=200ms+":0}
----------------------------------------------------------------
[proxy.js:120000] normal   , 53866 created, 84260 requestFinished, 1.56 req/socket, 0 requests, 0 sockets
{" <10ms":75," <15ms":1112," <20ms":10947," <30ms":32130," <40ms":8228," <50ms":3002," <100ms":4274," <150ms":181," <200ms":18," >=200ms+":33}

License

MIT

Contributors

fengmk2	dead-horse	AndrewLeedham	ngot	wrynearson	aaronArinder
alexpenev-s	blemoine	bdehamer	DylanPiercey	cixel	HerringtonDarkholme
denghongcai	kibertoad	pangorgo	mattiash	pmalouin	SimenB
vinaybedre	starkwang	killagu	tony-gutierrez	whxaxes

This project follows the git-contributor spec, auto updated at Mon Mar 06 2023 12:29:54 GMT+0800.