BalancerInherit, ProxyPassInherit: docs and code inconsistent

[Rainer Jung <ra...@kippdata.de>]

Docs say: "Disabling ProxyPassInherit also disables BalancerInherit."

Code (2.4) says:

if (ps->inherit || ps->ppinherit) {
     ps->workers = apr_array_append(p, base->workers, overrides->workers);
     ps->balancers = apr_array_append(p, base->balancers, 
overrides->balancers);
}

and both inherit flags are set by default. So in order to disable worker 
inheritance, you currently have to set both

ProxyPassInherit Off
BalancerInherit Off

Only setting "BalancerInherit Off" or setting "ProxyPassInherit Off" 
doesn't turn inheritance off.

I would have expected:

ProxyPassInherit Off => disables ProxyPass inheritance (works)
BalancerInherit Off  => disables Balancer/Worker inheritance (does not work)

Any side effects from one to the other are IMHO questionable. There are 
cases where both directions make sense but also where you don't want it. 
But we have documented the side effect from ProxyPassInherit to 
BalancerInherit so probably should stick to it (although it had not 
worked). I would prefer that one could overwrite "Disabling 
ProxyPassInherit also disables BalancerInherit." by explicitly setting 
"BalancerInherit On".

That would mean changing code to

if (ps->inherit && (ps->ppinherit || ps->inherit_set)) {
     ps->workers = apr_array_append(p, base->workers, overrides->workers);
     ps->balancers = apr_array_append(p, base->balancers, 
overrides->balancers);
}

so we inherit workers only if BalancerInherit is On and either 
ProxyPassInherit is On or BalancerInherit was set to On explicitly.

Any comments? Otherwise I would go ahead and apply for trunk and propose 
for backport.

Regards,

Rainer

Re: BalancerInherit, ProxyPassInherit: docs and code inconsistent

[Jim Jagielski <ji...@jaguNET.com>]

Let me check my notes on regarding the issue associated with
that implementation... as well as what the "correct" behavior
should be ;)

> On Aug 14, 2015, at 6:06 AM, Rainer Jung <ra...@kippdata.de> wrote:
> 
> Docs say: "Disabling ProxyPassInherit also disables BalancerInherit."
> 
> Code (2.4) says:
> 
> if (ps->inherit || ps->ppinherit) {
>    ps->workers = apr_array_append(p, base->workers, overrides->workers);
>    ps->balancers = apr_array_append(p, base->balancers, overrides->balancers);
> }
> 
> and both inherit flags are set by default. So in order to disable worker inheritance, you currently have to set both
> 
> ProxyPassInherit Off
> BalancerInherit Off
> 
> Only setting "BalancerInherit Off" or setting "ProxyPassInherit Off" doesn't turn inheritance off.
> 
> I would have expected:
> 
> ProxyPassInherit Off => disables ProxyPass inheritance (works)
> BalancerInherit Off  => disables Balancer/Worker inheritance (does not work)
> 
> Any side effects from one to the other are IMHO questionable. There are cases where both directions make sense but also where you don't want it. But we have documented the side effect from ProxyPassInherit to BalancerInherit so probably should stick to it (although it had not worked). I would prefer that one could overwrite "Disabling ProxyPassInherit also disables BalancerInherit." by explicitly setting "BalancerInherit On".
> 
> That would mean changing code to
> 
> if (ps->inherit && (ps->ppinherit || ps->inherit_set)) {
>    ps->workers = apr_array_append(p, base->workers, overrides->workers);
>    ps->balancers = apr_array_append(p, base->balancers, overrides->balancers);
> }
> 
> so we inherit workers only if BalancerInherit is On and either ProxyPassInherit is On or BalancerInherit was set to On explicitly.
> 
> Any comments? Otherwise I would go ahead and apply for trunk and propose for backport.
> 
> Regards,
> 
> Rainer