Debugging and Profiling mod_perl Applications
Because of the added complexity of being inside of the Apache web server, debugging mod_perl applications is often not as straightforward as it is with regular Perl programs or CGIs. Is the problem with your code, Apache, a CPAN module you are using, or within mod_perl itself? How do you tell? Sometimes traditional debugging techniques will not give you enough information to find your problem. Perhaps, instead, you're baffled as to why some code you just wrote is running so slow. You're probably asking yourself, "Isn't this mod_perl stuff supposed to improve my code's performance?" Don't worry, slow code happens even to the best of us. How do you profile your code to find the problem? This article shows how to use the available CPAN modules to debug and profile your mod_perl applications.
For Perl Programmers : only
Have you ever wished that you could have more than one version of a Perl module installed on your system, and that you could easily tell Perl exactly which one you wanted to load? Perhaps you have some legacy programs that only run with older versions of certain modules, while the rest of your system is coded to the more-modern versions of the same module. Or maybe you administer a multiuser system, where your various users request different module versions.
Installing mod_perl without superuser privileges
As you have seen from my previous articles, mod_perl enabled Apache consists of two main components: Perl modules and Apache itself. While installing Apache without root privileges is easy, one should know how to install Perl modules in a nonsystem-wide location. In this article, I'll demonstrate ways to complete this task.
mod_perl in 30 minutes
In this article I'll show step-by-step installation and configuration scenarios, and chances are you will be able to run the basic statically compiled mod_perl setup without reading any other documents. Of course, you will want and need to read the documentation later, but I think you will agree with me that it's ultimately cool to be able to get your feet wet without knowing much about the new technology up-front.
The Perl Basics You Need To Know
You will discover these important Perl basics invaluable when you start coding for mod_perl. I will start with pure Perl notes and gradually move to explaining the peculiarities of coding for mod_perl, presenting the traps one might fall into and explaining things obvious for some of us but may be not for the others.
The Perl You Need To Know
Before I delve into the details of mod_perl programming, it's probably a good idea to review some important Perl basics. You will discover these invaluable when you start coding for mod_perl. I will start with pure Perl notes and gradually move to explaining the peculiarities of coding for mod_perl, presenting the traps one might fall into and explaining things obvious for some of us but may be not for the others.
Writing mod_perl Handlers and Scripts
This chapter covers the mod_perl coding specifics, different from normal Perl coding. Most other perl coding issues are covered in the perl manpages and rich literature.
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