share TLS sessions in HTTPS client agent

[othiym23]

TLS session creation is expensive in high-load scenarios (like SSL termination on load balancers). It would be very useful for core to offer an option on the agent to pool TLS connections or otherwise minimize session creation for clients that are going to be sending lots of SSL traffic to a specific host. This can be worked around with a custom Agent, but it's a common enough use case (and has a small enough API surface) that it would be worth the effort to bring into core.

[indutny]

Considering maxSockets: 1, suggested by @tjfontaine, resolving this ticket would require reusing sessions between clients in agent pool.

[bodokaiser]

@indutny @othiym23 any updates on this? https.request takes at the moment 6x more time then xhrs from chrome canary.

[bodokaiser]

This paypal blog post shares some interesting insights.

I did not get how overwriting Agent.prototype.createConnection works. Also I using the alternative cipher with the ssl key and cert slowed done the requests to ~800ms.

However I got success by setting these options:

var agent = new https.Agent({
  "keepAlive": true,
  "keepAliveMsecs": 3000,
  "maxSockets": 100
});

This boils request time down to ~210ms which is OK for the moment.

[jasnell]

@othiym23 @indutny ... any further thoughts on this?

[indutny]

Going to take a look.

[indutny]

Fix is here: nodejs/node#2228