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

1$ 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

1const http = require('http');
2const Agent = require('agentkeepalive');
3
4const keepaliveAgent = new Agent({
5  maxSockets: 100,
6  maxFreeSockets: 10,
7  timeout: 60000, // active socket keepalive for 60 seconds
8  freeSocketTimeout: 30000, // free socket keepalive for 30 seconds
9});
10
11const options = {
12  host: 'cnodejs.org',
13  port: 80,
14  path: '/',
15  method: 'GET',
16  agent: keepaliveAgent,
17};
18
19const req = http.request(options, res => {
20  console.log('STATUS: ' + res.statusCode);
21  console.log('HEADERS: ' + JSON.stringify(res.headers));
22  res.setEncoding('utf8');
23  res.on('data', function (chunk) {
24    console.log('BODY: ' + chunk);
25  });
26});
27req.on('error', e => {
28  console.log('problem with request: ' + e.message);
29});
30req.end();
31
32setTimeout(() => {
33  if (keepaliveAgent.statusChanged) {
34    console.log('[%s] agent status changed: %j', Date(), keepaliveAgent.getCurrentStatus());
35  }
36}, 2000);
37

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:

1{
2  createSocketCount: 10,
3  closeSocketCount: 5,
4  timeoutSocketCount: 0,
5  requestCount: 5,
6  freeSockets: { 'localhost:57479:': 3 },
7  sockets: { 'localhost:57479:': 5 },
8  requests: {}
9}

Support https

1const https = require('https');
2const HttpsAgent = require('agentkeepalive').HttpsAgent;
3
4const keepaliveAgent = new HttpsAgent();
5// https://www.google.com/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8
6const options = {
7  host: 'www.google.com',
8  port: 443,
9  path: '/search?q=nodejs&sugexp=chrome,mod=12&sourceid=chrome&ie=UTF-8',
10  method: 'GET',
11  agent: keepaliveAgent,
12};
13
14const req = https.request(options, res => {
15  console.log('STATUS: ' + res.statusCode);
16  console.log('HEADERS: ' + JSON.stringify(res.headers));
17  res.setEncoding('utf8');
18  res.on('data', chunk => {
19    console.log('BODY: ' + chunk);
20  });
21});
22
23req.on('error', e => {
24  console.log('problem with request: ' + e.message);
25});
26req.end();
27
28setTimeout(() => {
29  console.log('agent status: %j', keepaliveAgent.getCurrentStatus());
30}, 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.

1const http = require('http');
2const Agent = require('agentkeepalive');
3const agent = new Agent();
4
5const req = http
6  .get('http://localhost:3000', { agent }, (res) => {
7    // ...
8  })
9  .on('error', (err) => {
10    if (req.reusedSocket && err.code === 'ECONNRESET') {
11      // retry the request or anything else...
12    }
13  })

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:

1cd benchmark
2sh 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):

1Transactions:          60000 hits
2Availability:         100.00 %
3Elapsed time:          29.70 secs
4Data transferred:        14.88 MB
5Response time:            0.03 secs
6Transaction rate:      2020.20 trans/sec
7Throughput:           0.50 MB/sec
8Concurrency:           59.84
9Successful transactions:       60000
10Failed transactions:             0
11Longest transaction:          0.15
12Shortest transaction:         0.01

Normal agent:

1Transactions:          60000 hits
2Availability:         100.00 %
3Elapsed time:          46.53 secs
4Data transferred:        14.88 MB
5Response time:            0.05 secs
6Transaction rate:      1289.49 trans/sec
7Throughput:           0.32 MB/sec
8Concurrency:           59.81
9Successful transactions:       60000
10Failed transactions:             0
11Longest transaction:          0.45
12Shortest transaction:         0.00

Socket created:

1[proxy.js:120000] keepalive, 50 created, 60000 requestFinished, 1200 req/socket, 0 requests, 0 sockets, 0 unusedSockets, 50 timeout
2{" <10ms":662," <15ms":17825," <20ms":20552," <30ms":17646," <40ms":2315," <50ms":567," <100ms":377," <150ms":56," <200ms":0," >=200ms+":0}
3----------------------------------------------------------------
4[proxy.js:120000] normal   , 53866 created, 84260 requestFinished, 1.56 req/socket, 0 requests, 0 sockets
5{" <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	nabeelbukhari	pmalouin
SimenB	vinaybedre	starkwang	killagu	tony-gutierrez	whxaxes

This project follows the git-contributor spec, auto updated at Sat Aug 05 2023 02:36:31 GMT+0800.