3 Catalyst::Manual::Deployment::Apache::mod_perl - Deploying Catalyst with mod_perl
5 =head1 mod_perl Deployment
7 The recommended method of deploying Catalyst applications is FastCGI. In
8 many cases, mod_perl is not the best solution, but we'll list some pros
9 and cons so you can decide for yourself.
15 mod_perl is fast, and your entire app will be loaded in memory within
18 =head3 Shared memory for multiple apps
20 If you need to run several Catalyst apps on the same server, mod_perl will
21 share the memory for common modules.
27 Since your application is fully loaded in memory, every Apache process will
28 be rather large. This means a large Apache process will be tied up while
29 serving static files, large files, or dealing with slow clients. For this
30 reason, it is best to run a two-tiered web architecture with a lightweight
31 frontend server passing dynamic requests to a large backend mod_perl
36 Any changes made to the code of your app require a full restart of
37 Apache. Catalyst does not support Apache::Reload or StatINC. This is
38 another good reason to run a frontend web server where you can set up an
39 C<ErrorDocument 502> page to report that your app is down for
42 =head4 Cannot run multiple versions of the same app
44 It is not possible to run two different versions of the same application in
45 the same Apache instance because the namespaces will collide.
47 =head3 Cannot run different versions of libraries
49 If you have two different applications which run on the same machine,
50 and each application needs a different versions of a library, the only
51 way to do this is to have per-vhost perl interpreters (with different
52 library paths). This is entirely possible, but nullifies all the memory
53 sharing benefits that you get from having multiple applications sharing
58 Now that we have that out of the way, let's talk about setting up mod_perl
59 to run a Catalyst app.
61 =head2 2. Install Apache with mod_perl
63 Both Apache 1.3 and Apache 2 are supported, although Apache 2 is highly
64 recommended. With Apache 2, make sure you are using the prefork MPM and not
65 the worker MPM. The reason for this is that many Perl modules are not
66 thread-safe and may have problems running within the threaded worker
67 environment. Catalyst is thread-safe however, so if you know what you're
68 doing, you may be able to run using worker.
70 In Debian, the following commands should get you going.
72 apt-get install apache2-mpm-prefork
73 apt-get install libapache2-mod-perl2
75 =head2 3. Configure your application
77 Every Catalyst application will automagically become a mod_perl handler
78 when run within mod_perl. This makes the configuration extremely easy.
79 Here is a basic Apache 2 configuration.
81 PerlSwitches -I/var/www/MyApp/lib
86 PerlResponseHandler MyApp
89 The most important line here is C<PerlModule MyApp>. This causes mod_perl
90 to preload your entire application into shared memory, including all of your
91 controller, model, and view classes and configuration. If you have -Debug
92 mode enabled, you will see the startup output scroll by when you first
95 For an example Apache 1.3 configuration, please see the documentation for
96 L<Catalyst::Engine::Apache::MP13>.
100 That's it, your app is now a full-fledged mod_perl application! Try it out
101 by going to http://your.server.com/.
105 =head2 Non-root location
107 You may not always want to run your app at the root of your server or virtual
108 host. In this case, it's a simple change to run at any non-root location
113 PerlResponseHandler MyApp
116 When running this way, it is best to make use of the C<uri_for> method in
117 Catalyst for constructing correct links.
119 =head2 Static file handling
121 Static files can be served directly by Apache for a performance boost.
123 DocumentRoot /var/www/MyApp/root
125 SetHandler default-handler
128 This will let all files within root/static be handled directly by Apache. In
129 a two-tiered setup, the frontend server should handle static files.
130 The configuration to do this on the frontend will vary.
132 Note the path of the application needs to be stated explicitly in the
133 web server configuration for this recipes.
137 Catalyst Contributors, see Catalyst.pm
141 This library is free software. You can redistribute it and/or modify it under
142 the same terms as Perl itself.