crypto/tls: session resumption (session id caching)

[tam7t]

What version of Go are you using (go version)?

go version go1.7.4 darwin/amd64

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"

What did you do?

I have 2 web servers, one that supports TLS session resumption based on a session cache and another that supports session cache and session tickets.

https://play.golang.org/p/9n4OZRjqHh

What did you expect to see?

I had expected the 2nd connection to each server to resume the session.

What did you see instead?

DidResume is only true for the server that supports session ticket resumption.

It appears that session ID caching is not supported in client or server mode. Perhaps the documentation for ClientSessionCache could be a bit more explicit that it is only a cache for session tickets.

[FiloSottile]

Session ID caching is not supported in neither client nor server.

I guess the client side can be documented in Config.ClientSessionCache. Not sure where the docs for the server side could go.

I had to look at the code myself a week ago to confirm this.

[Kanshiroron]

Any plan on implementing it?
The thing is without this feature, it's impossible to configure a load balancer with sticky TLS sessions (without TLS offload)

[FiloSottile]

No plans I'm aware of. You can open a new issue to request the feature.

Almost sure you could implement sticky TLS on top of tickets with #19199, but the discussion should move away from this closed issue.