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Module::Build::Cookbook

Section: User Contributed Perl Documentation (3pm)

Updated: 2014-09-19

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NAME

Module::Build::Cookbook - Examples of Module::Build Usage

DESCRIPTION

isn't conceptually very complicated, but examples are always helpful. The following recipes should help developers and/or installers put together the pieces from the other parts of the documentation.

BASIC RECIPES

Installing modules that use Module::Build

In most cases, you can just issue the following commands:

There's nothing complicated here - first you're running a script called Build.PL, then you're running a (newly-generated) script called Build and passing it various arguments.

The exact commands may vary a bit depending on how you invoke perl scripts on your system. For instance, if you have multiple versions of perl installed, you can install to one particular perl's library directories like so:

If you're on Windows where the current directory is always searched first for scripts, you'll probably do something like this:

On the old Mac OS (version 9 or lower) using MacPerl, you can double-click on the Build.PL script to create the Build script, then double-click on the Build script to run its , , and actions.

The Build script knows what perl was used to run Build.PL, so you don't need to re-invoke the Build script with the complete perl path each time. If you invoke it with the wrong perl path, you'll get a warning or a fatal error.

Modifying Config.pm values

relies heavily on various values from perl's to do its work. For example, default installation paths are given by and and friends, C linker & compiler settings are given by , , , , and so on. If you're pretty sure you know what you're doing, you can tell to pretend there are different values in Config.pm than what's really there, by passing arguments for the parameter on the command line:
Inside the script the same thing can be accomplished by passing values for the parameter to :

In custom build code, the same thing can be accomplished by calling the ``config'' in Module::Build method:

Installing modules using the programmatic interface

If you need to build, test, and/or install modules from within some other perl code (as opposed to having the user type installation commands at the shell), you can use the programmatic interface. Create a Module::Build object (or an object of a custom Module::Build subclass) and then invoke its method to run various actions.
The first argument to is the name of the action, and any following arguments are named parameters.

This is the interface we use to test Module::Build itself in the regression tests.

Installing to a temporary directory

To create packages for package managers like RedHat's or Debian's , you may need to install to a temporary directory first and then create the package from that temporary installation. To do this, specify the parameter to the action:

This essentially just prepends all the installation paths with the /tmp/my-package-1.003 directory.

Installing to a non-standard directory

To install to a non-standard directory (for example, if you don't have permission to install in the system-wide directories), you can use the or parameters:

See ``INSTALL PATHS'' in Module::Build for a much more complete discussion of how installation paths are determined.

Installing in the same location as ExtUtils::MakeMaker

With the introduction of in Module::Build 0.28 and in 6.31 its easy to get them both to install to the same locations.
First, ensure you have at least version 0.28 of Module::Build installed and 6.31 of . Prior versions have differing (and in some cases quite strange) installation behaviors.
The following installation flags are equivalent between and .
For example, if you are currently installing modules with this command:

You can install into the same location with Module::Build using this:

"prefix" vs "install_base"

The behavior of is complicated and depends on how your Perl is configured. The resulting installation locations will vary from machine to machine and even different installations of Perl on the same machine. Because of this, it's difficult to document where will place your modules.
In contrast, has predictable, easy to explain installation locations. Now that and both have there is little reason to use other than to preserve your existing installation locations. If you are starting a fresh Perl installation we encourage you to use . If you have an existing installation installed via , consider moving it to an installation structure matching and using that instead.

Running a single test file

supports running a single test, which enables you to track down errors more quickly. Use the following format:

In addition, you may want to run the test in verbose mode to get more informative output:

I run this so frequently that I define the following shell alias:

So then I can just execute to run a single test.

ADVANCED RECIPES

Making a CPAN.pm-compatible distribution

New versions of CPAN.pm understand how to use a Build.PL script, but old versions don't. If authors want to help users who have old versions, some form of Makefile.PL should be supplied. The easiest way to accomplish this is to use the parameter to in the script, which can create various flavors of Makefile.PL during the action.

As a best practice, we recommend using the ``traditional style of Makefile.PL'' unless your distribution has needs that can't be accomplished that way.

The module, which is part of 's distribution, is responsible for creating these Makefile.PLs. Please see Module::Build::Compat for the details.

Changing the order of the build process

The property specifies the steps will take when building a distribution. To change the build order, change the order of the entries in that property:
Currently, has the following default value:
Do take care when altering this property, since there may be non-obvious (and non-documented!) ordering dependencies in the code.

Adding new file types to the build process

Sometimes you might have extra types of files that you want to install alongside the standard types like .pm and .pod files. For instance, you might have a Bar.dat file containing some data related to the module and you'd like for it to end up as Foo/Bar.dat somewhere in perl's path so can access it easily at runtime. The following code from a sample file demonstrates how to accomplish this:
This will find all .dat files in the lib/ directory, copy them to the blib/lib/ directory during the action, and install them during the action.
If your extra files aren't located in the directory in your distribution, you can explicitly say where they are, just as you'd do with .pm or .pod files:
If your extra files actually need to be created on the user's machine, or if they need some other kind of special processing, you'll probably want to subclass and create a special method to process them, named :

If your extra files don't go in lib/ but in some other place, see ``Adding new elements to the install process'' for how to actually get them installed.

Please note that these examples use some capabilities of Module::Build that first appeared in version 0.26. Before that it could still be done, but the simple cases took a bit more work.

Adding new elements to the install process

By default, Module::Build creates seven subdirectories of the blib directory during the build process: lib, arch, bin, script, bindoc, libdoc, and html (some of these may be missing or empty if there's nothing to go in them). Anything copied to these directories during the build will eventually be installed during the action (see ``INSTALL PATHS'' in Module::Build.
If you need to create a new custom type of installable element, e.g. , then you need to tell Module::Build where things in blib/conf/ should be installed. To do this, use the parameter to the method:
Or you can call the method later:

The user may also specify the path on the command line:

The important part, though, is that somehow the install path needs to be set, or else nothing in the blib/conf/ directory will get installed, and a runtime error during the action will result.

See also ``Adding new file types to the build process for how to create the stuff in blib/conf/'' in the first place.

EXAMPLES ON CPAN

Several distributions on CPAN are making good use of various features of Module::Build. They can serve as real-world examples for others.

SVN-Notify-Mirror

<http://search.cpan.org/~jpeacock/SVN-Notify-Mirror/>

John Peacock, author of the distribution, says:
1. Using "auto_features", I check to see whether two optional modules are available - SVN
:Notify::Config and Net::SSH;
2. If the S
:N::Config module is loaded, I automatically generate test files for it during Build (using the "PL_files" property).

:3. If the "ssh_feature" is available, I ask if the user wishes to perform the ssh tests (since it requires a little preliminary setup);

4. Only if the user has "ssh_feature" and answers yes to the testing, do I generate a test file.
I'm sure I could not have handled this complexity with EU::MM, but it was very easy to do with M::B.:

Modifying an action

Sometimes you might need an to have an action, say , do something unusual. For instance, you might need to change the ownership of a file or do something else peculiar to your application.
You can subclass on the fly using the method and override the methods that perform the actions. You may need to read through and to find the methods you want to override. All ``action methods are implemented by a method called ``ACTION_ followed by the action's name, so here's an example of how it would work for the action:

Adding an action

You can add a new action simply by writing the method for it in your subclass. Use to declare that another action must have been run before your action.
For example, let's say you wanted to be able to write to test your code and commit it to Subversion.

Bundling Module::Build

Note: This section probably needs an update as the technology improves (see contrib/bundle.pl in the distribution).

Suppose you want to use some new-ish features of Module::Build, e.g. newer than the version of Module::Build your users are likely to already have installed on their systems. The first thing you should do is set to your minimum version of Module::Build. See Module::Build::Authoring.
But not every build system honors yet. Here's how you can ship a copy of Module::Build, but still use a newer installed version to take advantage of any bug fixes and upgrades.

First, install Module::Build into Your-Project/inc/Module-Build. CPAN will not index anything in the inc directory so this copy will not show up in CPAN searches.

You should now have all the Module::Build .pm files in Your-Project/inc/Module-Build/lib/perl5.

Next, add this to the top of your Build.PL.

And write the rest of your Build.PL normally. Module::Build will remember your change to and use it when you run ./Build.
In the future, we hope to provide a more automated solution for this scenario; see in the Module::Build distribution for one indication of the direction we're moving.

AUTHOR

Ken Williams <[email protected]>

COPYRIGHT

Copyright (c) 2001-2008 Ken Williams. All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

perl?(1), Module::Build?(3), Module::Build::Authoring?(3), Module::Build::API?(3)


Index

NAME

DESCRIPTION

BASIC RECIPES

Installing modules that use Module::Build

Modifying Config.pm values

Installing modules using the programmatic interface

Installing to a temporary directory

Installing to a non-standard directory

Installing in the same location as ExtUtils::MakeMaker

Running a single test file

ADVANCED RECIPES

Making a CPAN.pm-compatible distribution

Changing the order of the build process

Adding new file types to the build process

Adding new elements to the install process

EXAMPLES ON CPAN

SVN-Notify-Mirror

Modifying an action

Adding an action

Bundling Module::Build

AUTHOR

COPYRIGHT

SEE ALSO