Add Exception Hooks to 2.0

[Paul Querna <ch...@force-elite.com>]

Exception hooks are awesome.  Quite possibly the best thing since sliced
bread for module developers!

It is difficult to get users to install httpd 2.1, so I would like to
see the exception hooks added to the 2.0 branch.  mod_backtrace is very
helpful for catching problems under high load and other situations where
running under GDB is not feasible.  

mod_backtrace is also no longer Linux specific, It can now work under
FreeBSD once 'libexecinfo' is installed from the FreeBSD Ports system.

Can we get some binding votes on this?

-Paul Querna

Re: Add Exception Hooks to 2.0

[Jeff Trawick <tr...@attglobal.net>]

Paul Querna wrote:
> Exception hooks are awesome.  Quite possibly the best thing since sliced
> bread for module developers!

No, I didn't pay Paul to say that :)

> It is difficult to get users to install httpd 2.1, so I would like to
> see the exception hooks added to the 2.0 branch.  mod_backtrace is very
> helpful for catching problems under high load and other situations where
> running under GDB is not feasible.
> 
> mod_backtrace is also no longer Linux specific, It can now work under
> FreeBSD once 'libexecinfo' is installed from the FreeBSD Ports system.
> 
> Can we get some binding votes on this?

There are more than just a few lines of code required to merge the exception 
hooks into the stable branch.  Two pieces:

a) move to common sync signal setup/signal handler for Unix MPMs
b) implement the exception hook from that common signal handler

I have a hunch (but incomplete data is available) that a) will resolve at least 
one of a couple of glitches at stable, so there may be other reasons to do 
this.  The glitches are

i. gprof at stable requires special compile flag affecting sync sig setup to 
work, but doesn't require it at 2.1 HEAD; not tested personally; somebody 
reported it to the list last fall
ii. cgid daemon restart logic, the merge of which I continue to sit on, shows 
some non-portable differences in signal handling at stable that I don't see at head

In the next day or so (i.e., bug me directly by Thursday if I have dropped the 
ball ;) ) I'll put together a list of required changes to the stable branch, 
make sure it works, and propose a merge in STATUS.

Re: Add Exception Hooks to 2.0

[Jeff Trawick <tr...@attglobal.net>]

Jeff Trawick wrote:
> Mads Toftum wrote:
> 
>> On Thu, Feb 12, 2004 at 06:39:43AM -0500, Jeff Trawick wrote:
>>
>>> It applies and builds cleanly for me with HEAD of APACHE_2_0_BRANCH 
>>> but I have not had time to test as of yet.  Once I can do so, I'll 
>>> add a vote to the STATUS file.  If you do try it out, post your 
>>> results ;)
>>>
>>
>> Tested on linux with prefork and worker - seems to work well. All that 
>> seems
>> to be missing are the config directives.

done...  see proposed merge in APACHE_2_0_BRANCH/STATUS...

Re: Add Exception Hooks to 2.0

[Jeff Trawick <tr...@attglobal.net>]

Mads Toftum wrote:
> On Thu, Feb 12, 2004 at 06:39:43AM -0500, Jeff Trawick wrote:
> 
>>It applies and builds cleanly for me with HEAD of APACHE_2_0_BRANCH but I 
>>have not had time to test as of yet.  Once I can do so, I'll add a vote to 
>>the STATUS file.  If you do try it out, post your results ;)
>>
> 
> Tested on linux with prefork and worker - seems to work well. All that seems
> to be missing are the config directives.

Also, I've tested the patch today on Solaris 9 with prefork and worker and 
threadpool.

Yes, the difference between 1.3 and 2.1-dev w.r.t. the config directive is 
glaring :(  I'll try to commit a remedy to 2.1-dev soonish, and add that to the 
patch for hopeful backport to APACHE_2_0_BRANCH.

Thanks for your testing and feedback,

Jeff

Re: Add Exception Hooks to 2.0

[Mads Toftum <ma...@toftum.dk>]

On Thu, Feb 12, 2004 at 06:39:43AM -0500, Jeff Trawick wrote:
> It applies and builds cleanly for me with HEAD of APACHE_2_0_BRANCH but I 
> have not had time to test as of yet.  Once I can do so, I'll add a vote to 
> the STATUS file.  If you do try it out, post your results ;)
> 
Tested on linux with prefork and worker - seems to work well. All that seems
to be missing are the config directives.

vh

Mads Toftum
-- 
`Darn it, who spiked my coffee with water?!' - lwall

Re: Add Exception Hooks to 2.0

[Jeff Trawick <tr...@attglobal.net>]

Paul Querna wrote:

> It is difficult to get users to install httpd 2.1, so I would like to
> see the exception hooks added to the 2.0 branch.  mod_backtrace is very
> helpful for catching problems under high load and other situations where
> running under GDB is not feasible.  

A patch for adding exception hooks to 2.0 branch is at

http://www.apache.org/~trawick/fatal_exception_20.patch

It applies and builds cleanly for me with HEAD of APACHE_2_0_BRANCH but I have 
not had time to test as of yet.  Once I can do so, I'll add a vote to the 
STATUS file.  If you do try it out, post your results ;)

Thanks,

Jeff