Apache::Reload question...
I've got a "reality check" question for people to see that I'm not missing something obvious with our Apache::Reload mod_perl setup. We've recently install Apache::Reload at our site in production and it's working great. In what isprobably not the best 'software engineering' style, we've been known to upload several small patches in a single day and used to have to do short restarts to integrate the new code. We now use Apache::Reload instead. Rather than putting 'use Apache::Reload' in each of our modules, I've created a touch file, which after looking through the Apache::Reload code, I noted that you could put a list of modules into it which would be reloaded. On top of this, weuse mod_accelas a front end to our mod_perl backend.This combination seems to work great as well for anyone curious. The question I had regards where to put the 'Apache::Reload' directive. The documentation suggests something like: PerlInitHandler Apache::Reload PerlSetVar ReloadAll Off PerlSetVar ReloadTouchFile /tmp/reload_modules The problem I see in a production machine is that each child process will see this on the next request, and attempt to reload it's modules. At that point, you'll loose the shared memory the modules use between child processes. On top of this, the parent process will never get this, so it will never reload modules in the parent.The next time a new child is forked, on the first request it receives it will again attempt to reload the changed modules. Is this correct? Or am I missing something? The alternative I've used is this: PerlRestartHandler Apache::Reload PerlSetVar ReloadAll Off PerlSetVar ReloadTouchFile /tmp/reload_modules Then when I've uploaded any changes, I touch the change file, and do an 'apachectl graceful' to restart the backend. I think this works nicely because: 1)The mod_accel front end will buffer any long file uploads, and any long file downloads. So the actual length of connections from the frontend to the backend is only as long as it takes to process the request and tunnel the data betwen the front-back or back-front. Thus the 'graceful' restart only ever takes a few seconds, and no connections are ever lost, only blocked for a few seconds at the most (the length of the longest request to process). 2) Doing it in the restart handler means that the parent process reloads the modules, and all the newly forked children have shared copies. Can anyone tell me if I'm missing something here? Rob
Re: Apache::Reload question...
The question I had regards where to put the 'Apache::Reload' directive. The documentation suggests something like: PerlInitHandler Apache::Reload PerlSetVar ReloadAll Off PerlSetVar ReloadTouchFile /tmp/reload_modules The problem I see in a production machine is that each child process will see this on the next request, and attempt to reload it's modules. At that point, you'll loose the shared memory the modules use between child processes. that sounds right to me On top of this, the parent process will never get this, so it will never reload modules in the parent. The next time a new child is forked, on the first request it receives it will again attempt to reload the changed modules. Is this correct? Or am I missing something? I'm not sure about that. The alternative I've used is this: PerlRestartHandler Apache::Reload PerlSetVar ReloadAll Off PerlSetVar ReloadTouchFile /tmp/reload_modules Then when I've uploaded any changes, I touch the change file, and do an 'apachectl graceful' to restart the backend. I think this works nicely because: [snip] 2) Doing it in the restart handler means that the parent process reloads the modules, and all the newly forked children have shared copies. Can anyone tell me if I'm missing something here? that sounds right to me. I've not tested it with Apache::Reload specifically, but I did test using Apache::RegistryLoader with a PerlRestartHandler to reload Registry scripts in the parent process on restart and it seemed to work as we both suspected (recipe 17.4 bears the fruit of this labor :) I suspect that it is the same with Apache::Reload unless there is something specific to the reloading logic that prevents it. --Geoff
Apache::Reload question
Can Apache::Reload be used to reload modules that are use-d by httpd PerlModule, PerlRequire, or PerlHandler directives, or do they have to be explicitly use-d in code that is inside a handler? I think the answer is yes - these are no different than anything else except that memory sharing is lost because reload occurs in the children but wanted to check before I go down that path. Matthew Pressly
One more small Apache::Reload question
First, thanks to all the great suggestions, it looks like it works fine. However, now my logs are loaded with a ton of subroutine redefined warnings (which is normal I suppose?). I can certainly live with this in a development environment, but thought I would check to see if it is expected, and if it can be turned off while still enabling Reload. Thanks! Bryan
RE: One more small Apache::Reload question
Those warnings are normal, and you can use the warnings pragma to turn them off. (Although, I believe the warnings pragma only exists in Perl 5.6.0+). use warnings; no warnings qw(redefine); - Kyle -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Bryan Coon Sent: Wednesday, August 01, 2001 9:36 AM To: '[EMAIL PROTECTED]' Subject: One more small Apache::Reload question First, thanks to all the great suggestions, it looks like it works fine. However, now my logs are loaded with a ton of subroutine redefined warnings (which is normal I suppose?). I can certainly live with this in a development environment, but thought I would check to see if it is expected, and if it can be turned off while still enabling Reload. Thanks! Bryan
RE: One more small Apache::Reload question
However, now my logs are loaded with a ton of subroutine redefined warnings (which is normal I suppose?). I can certainly live with this in a development environment, but thought I would check to see if it is expected, and if it can be turned off while still enabling Reload. Well, first of all, you will want to turn off Apache::Reload during production. All of those stat()'s will slow down your server speed significantly, as the disk is kept busy for each request. Secondly, how is it you view your logs? I have a window running tail -f with a grep filter: tail -f /var/log/httpd/error_log | egrep -v 'redefined.at|Apache::Reload|AuthenCache' This way, I get the best of both worlds, by ignoring the noise: # use constant SIGNATURE = 'TSTAT'; Constant subroutine SIGNATURE redefined at /usr/lib/perl5/5.00503/constant.pm line 175. # One of my module's subroutines.. there are 15 of these Subroutine test_handler redefined at /etc/httpd/lib/perl/Stat/Count.pm line 315 I have AuthenCache in my filter because at LogLevel debug, Apache::AuthenCache is *noisy*!! HTH! L8r, Rob #!/usr/bin/perl -w use Disclaimer qw/:standard/;
