On 2012-04-26 11:57, Waldemar Klein wrote:
Thanks, that already helped a lot.
I had this "post_config hook" thing somewhere in the back of my mind,
but didn't connect it with my problem as a possible solution. While
googling for it I also found child_init hook. I created logs to see
when those are called, and it seems the child_init hook is ONLY called
in the last, the "real working" configuration. I tested this with
direct calling (-X), as service (-k start/stop/restart) and also when
the service is started on boot, and it seems to work the same way
always. So, I'll just transfer all the heavy work to the child_init
hook.
In the process I also found out that I can store data in the in a pool
itself (i.e. not only allocating memory, but in a hash or table linked
to the pool), which I wasn't aware is possible. This was my first plan
to use to store a boolean variable, but the way child_init behaves, I
won't need this, it might come in handy in the future. This is done
with apr_pool_userdata_set and apr_pool_userdata_get.
This is only for Apache on Windows, didn't try it on Linux. If I ever
have to get it running on Linux, I'll cross that bridge when I come to
it*
Again, I don't know how the permissions work in Windows. In Linux, the
child_init hook is called by the non-privileged apache children. The
post_config is called by the privileged parent.
Also, post_config is not called by the children. They get the modifs
made in post_config through the inheritence that comes with process
spawning because the parent runs post_config _before_ spawning its children.
If you put your heavy lifting in child_init, it will be executed every
time the parent creates a child. So child creation will be slow.
Children are often killed and recreated (they may have a finite upper
bound on the number of requests they process), so child creation just
happens even if your load is constant and no extra capacity would be needed.
I would put it in post_config. It is run a couple of times, apache
restart/reloads could be slow, but at least you know that once it
starts, it runs smoothly. At the end of the day, if you go for
child_init, you'll run the conf parsing many more times.
Sorin
