code review 7372054: net/http: add Transport.CancelRequest

net/http: add Transport.CancelRequest

Permits all sorts of custom HTTP timeout policies without
adding a new Transport timeout Duration for each combination
of HTTP phases.

This keeps track internally of which TCP connection a given
Request is on, and lets callers forcefully close the TCP
connection for a given request, without actually getting
the net.Conn directly.

Additionally, a future CL will implement res.Body.Close (Issue
3672) in terms of this.

Update issue 3362
Update issue 3672

[bradfitz, 2013-02-27 17:12:36]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[rsc, 2013-02-27 23:09:02]

API LGTM

[bradfitz, 2013-02-27 23:09:47]

R=adg for code review?

On Wed, Feb 27, 2013 at 3:09 PM, <rsc@golang.org> wrote:

> API LGTM
>
>
>
https://codereview.appspot.**com/7372054/<https://codereview.appspot.com/7372...
>

[adg, 2013-02-27 23:13:43]

LGTM

https://codereview.appspot.com/7372054/diff/5001/src/pkg/net/http/transport_t...
File src/pkg/net/http/transport_test.go (right):

https://codereview.appspot.com/7372054/diff/5001/src/pkg/net/http/transport_t...
src/pkg/net/http/transport_test.go:1200: if d < 500*time.Millisecond {
what about d > 1.5*time.Second ?

[bradfitz, 2013-02-27 23:15:43]

https://codereview.appspot.com/7372054/diff/5001/src/pkg/net/http/transport_t...
File src/pkg/net/http/transport_test.go (right):

https://codereview.appspot.com/7372054/diff/5001/src/pkg/net/http/transport_t...
src/pkg/net/http/transport_test.go:1200: if d < 500*time.Millisecond {
On 2013/02/27 23:13:43, adg wrote:
> what about d > 1.5*time.Second ?

If it's going to be >1 second, it's probably because it failed to cancel and
it's going to be like 30 seconds and the test will fail for timeout reasons.

The <500 milliseconds was just to check for quick unrelated failures.  I wanted
to write <25 milliseconds but I knew that'd be flaky.

[bradfitz, 2013-02-27 23:20:15]

*** Submitted as https://code.google.com/p/go/source/detail?r=bcecef1cb2fd ***

net/http: add Transport.CancelRequest

Permits all sorts of custom HTTP timeout policies without
adding a new Transport timeout Duration for each combination
of HTTP phases.

This keeps track internally of which TCP connection a given
Request is on, and lets callers forcefully close the TCP
connection for a given request, without actually getting
the net.Conn directly.

Additionally, a future CL will implement res.Body.Close (Issue
3672) in terms of this.

Update issue 3362
Update issue 3672

R=golang-dev, rsc, adg
CC=golang-dev
https://codereview.appspot.com/7372054