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From: Eric Wong <e@80x24.org>
To: =?utf-8?Q?Br=C3=A1ulio?= Bhavamitra <braulio@eita.org.br>
Cc: unicorn-public <unicorn-public@bogomips.org>
Subject: Re: Master hooks needed
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Bráulio Bhavamitra <braulio@eita.org.br> wrote:
> The problem is actually worser, and the worker.nr == 0 can't be used.
> I had to do something like this:
> 
> master_run = true
> 
> before_fork do |server, worker|
>   if master_run
>      #warm up server...
> 
>      #kill old pid...
> 
>      #disconnect active record
> 
>      master_run = false
>   end
> 
>   # other stuff for each worker
> end
> 
> In the last example, using worker.nr == 0 would make the server crash
> in case the worker 0 was killed/restarted.
> 
> Also the AR's disconnect and *many other stuff* people put on
> before_fork should only be run once the master was preloaded, not for
> every worker.

AR disconnect! is idempotent and has been since unicorn existed.
I suspect most other things people run in before_fork are already
idempotent, too.

> So I still think at least a hook like master_preloaded(server) is necessary.

Using the local 'master_run' variable in your before_fork already
accomplishes everything you needed, right?

I try to keep unicorn as lean as possible and not bloat it with
redundant features.  The current hooks already fulfill the minimal
requirements for supporting apps which do not behave properly under
preload_app=true, so I am not convinced why a new hook is necessary.