launchpad-dev team mailing list archive

[Gavin Panella <gavin.panella@xxxxxxxxxxxxx>]

On 14 June 2011 12:06, Gavin Panella <gavin.panella@xxxxxxxxxxxxx> wrote:
[...]
> After your suggestion of looking at http://bugs.python.org/issue1652 I
> am now running a branch through ec2 to reset the SIGPIPE handler when
> spawning:
>
>  https://code.launchpad.net/~allenap/launchpad/rabbit-fixture-sigpipe/+merge/64531
>
> Let's see if this works!

It didn't.

However, I had some success today. I patched TestRabbitFixture to run
test_start_check_shutdown 1000 times. In ec2 it failed about 1 time in
100 with:

  Cookie file /.../.erlang.cookie must be accessible by owner only

This looks like a race! However, it isn't the same error as outlined
in bug 788557... but it's similar enough that perhaps fixing this
would fix both.

When the RabbitMQ daemon is spawned, the parent process immediately
starts checking the daemon's state by calling `rabbitmqctl -n
... status`, and thereafter a few times every second. The first
invocation of rabbitmqctl is likely racing with the daemon to create
the cookie file.

I patched up the fixture code - http://paste.ubuntu.com/627585/ - to
check for the cookie before running rabbitmqctl and ran the test
(again, 1000 times) in ec2 with no errors. \o/

It struck me that a simpler fix might simply be to run `rabbitmqctl -n
... status` at least once before starting the daemon. I'll prepare a
branch to do that in the morning.

Gavin.