code review 61570046: log/syslog: Add timeouts for syslog

log/syslog: Add timeouts for syslog

In order to detect dead syslog readers,
use a timout on (re-)connect and write.

Without this, programs hang in unixdomain sockets writes forever.

The timeouts are 1 seconds each and not configurable from the outside.

[ioe, 2014-02-12 10:36:08]

Hello rsc@golang.org, golang-codereviews@googlegroups.com (cc:
golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go

[ioe, 2014-02-12 21:33:13]

This change is the result of a discussion in 

https://groups.google.com/d/msg/golang-nuts/PMm8nH0yaoA/oyw1pEd_aigJ

and runs in production without any problem since two months.

I implemented it as a pure internal change without exposing the timeouts,
because it might by related to issue 5932.

If issue 5932 is not fixed for the Go 1.3 time frame, this change can mitigate
the issue reliably for syslog users connecting to /dev/log via unixdgram.

It can be removed any time later, without breaking apis.

[ioe, 2014-02-19 01:20:41]

Gentle ping.

On 2014/02/12 21:33:13, ioe wrote:
> This change is the result of a discussion in 
> 
> https://groups.google.com/d/msg/golang-nuts/PMm8nH0yaoA/oyw1pEd_aigJ
> 
> and runs in production without any problem since two months.
> 
> I implemented it as a pure internal change without exposing the timeouts,
> because it might by related to issue 5932.
> 
> If issue 5932 is not fixed for the Go 1.3 time frame, this change can mitigate
> the issue reliably for syslog users connecting to /dev/log via unixdgram.
> 
> It can be removed any time later, without breaking apis.

[bradfitz, 2014-03-19 17:44:10]

not lgtm

This hard-codes policy (1 second timeouts) in a package that we'd rather not
have in the standard library anyway.

If you need this functionality, the less offensive way is if you add something
like DialWithDialer (precedent:
http://tip.golang.org/pkg/crypto/tls/#DialWithDialer) or http's Transport.Dial
hook (http://tip.golang.org/pkg/net/http/#Transport), and then callers can plug
in any policy they want.

[ioe, 2014-03-21 05:23:40]

Sorry for the slow response, I am on vacation until 2nd of April.

Using a custom dialer is not enough, as it only solves the reconnect
problem. What I experienced in production was missing read/write timeouts
on unix domain sockets.

Any good pattern to abstract this?
On Mar 20, 2014 12:44 AM, <bradfitz@golang.org> wrote:

not lgtm

This hard-codes policy (1 second timeouts) in a package that we'd rather
not have in the standard library anyway.

If you need this functionality, the less offensive way is if you add
something like DialWithDialer (precedent:
http://tip.golang.org/pkg/crypto/tls/#DialWithDialer) or http's
Transport.Dial hook (http://tip.golang.org/pkg/net/http/#Transport), and
then callers can plug in any policy they want.


https://codereview.appspot.com/61570046/

[gobot, 2014-07-09 21:23:37]

R=close (assigned by r@golang.org)