http.globalAgent.maxSockets is not always respected

[cyrus-and]

Aborting a pending request (whose response is not read yet) causes http.globalAgent.maxSockets to not being respected for future requests.

Specifically:

• the response must contain some data;
• there must be a 'response' listener registered for the requests.

I can reproduce the issue with the following:

client.js:

var http = require('http');

http.globalAgent.maxSockets = 3;

for (var i = 0; i < 100; i++) {
    var request = http.get('http://127.0.0.1:8080', function () {
        // just register a listener...
    });
    request.setTimeout(1000, function () {
        console.log('T');
        this.abort();
    });
}

server.js:

require('http').createServer(function (reqest, response) {
    console.log('R');
    response.end('hello');
}).listen(8080);

Run server.js then client.js; the output of the former is:

R
R
R
# 1s timeout here...
R
R
R
R
R
R
# 1s timeout here...
R
R
R
R
R
R
R
R
R
R
R
R
# 1s timeout here...
[...]
# up to 100

I was expecting groups of three requests each, instead of: 100 = 3 + 6 + 12 + 24 + 48 + 7.
The output of client.js reflects the one of server.js.

This happen at least with v4.1.1 and v5.1.0.

---

I apologize if the above is the intended behavior and I'm just misunderstanding request.abort() and agent.maxSockets.

[claudiorodriguez]

It doesn't look like request.abort() frees the sockets in the agent. I tried keepAlive + maxFreeSockets but that didn't work either (all requests were sent at once).

Here's how I was able to get your example to work:

var http = require('http');

var agent = new http.Agent({
    maxSockets: 3
});

var reqConfig = {
    host: 'localhost',
    port: 8080,
    agent: agent
};

var i, cntRes = 0;
for (i = 0; i < 100; i++) {
    var request = http.get(reqConfig, function () {
        console.log(cntRes++);
        // just register a listener...
    });

    request.on("socket", function (socket) {
        socket.setTimeout(1000, function() {
           socket.end();
        });
    });
}

EDIT: socket.destroy() also works. I'm looking at request.abort's code and in theory it should call the same method (calls this.socket.destroy). So no idea why this is happening.

[mscdex]

This should be fixed by 6e11e22. Can you verify @cyrus-and?

[cyrus-and]

@mscdex everything is working as expected now, thanks.