Bráulio Bhavamitra <[email protected]> wrote:
> Hello all,
>
> If I need to hook something after master load, I'm currently doing:
>
> before_fork do |server, worker|
> # worker 0 is the first to init, so hold the master here
> if worker.nr == 0
> #warm up server...
>
> #kill old pid...
> end
>
> # other stuff for each worker
> end
>
> Both operations I currently do (server warm up and old pid kill) need
> to be run only once, and not for every worker as before_fork does,
> that's why I had to put the condition seen above.
The above is fine if your first worker never dies. I think you can add
a local variable to ensure it only runs the first time worker.nr == 0 is
started, in case a worker dies. Something like:
first = true
before_fork do |server, worker|
# worker 0 is the first to init, so hold the master here
if worker.nr == 0 && first
first = false
#warm up server...
#kill old pid...
end
# other stuff for each worker
end
For what it's worth, I'm not a fan of auto-killing the old PID in the
unicorn config and regret having it in the example config. It's only
for the most memory-constrained configs and fragile (because anything
with pid files is always fragile).
> So hooks for master is needed, something like
> master_after_load(server) and master_init(server).
>
> What do you think?
rack.git also has a Rack::Builder#warmup method. Aman originally
proposed it for unicorn, but it's useful outside of unicorn so
we moved it to Rack.
In general, I'm against adding new hooks/options because they tend to
make maintainability and documentation harder for ops folks.
I still have nightmares of some Capistrano config filled with hooks
from years ago :x
Features like these also makes migrating away from unicorn harder, so
that is another reason we ended up adding #warmup to Rack and not
unicorn.
