Module::Build::Cookbook - phpMan

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

DESCRIPTION
    "Module::Build" 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:

      perl Build.PL
      ./Build
      ./Build test
      ./Build install

    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:

      /usr/bin/perl5.8.1 Build.PL
      ./Build
      ./Build test
      ./Build install

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

      perl Build.PL
      Build
      Build test
      Build install

    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 "build", "test", and
    "install" 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
    "Module::Build" relies heavily on various values from perl's "Config.pm"
    to do its work. For example, default installation paths are given by
    "installsitelib" and "installvendorman3dir" and friends, C linker &
    compiler settings are given by "ld", "lddlflags", "cc", "ccflags", and
    so on. *If you're pretty sure you know what you're doing*, you can tell
    "Module::Build" to pretend there are different values in Config.pm than
    what's really there, by passing arguments for the "--config" parameter
    on the command line:

      perl Build.PL --config cc=gcc --config ld=gcc

    Inside the "Build.PL" script the same thing can be accomplished by
    passing values for the "config" parameter to "new()":

     my $build = Module::Build->new
       (
        ...
        config => { cc => 'gcc', ld => 'gcc' },
        ...
       );

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

     $build->config( cc => 'gcc' );     # Set
     $build->config( ld => 'gcc' );     # Set
     ...
     my $linker = $build->config('ld'); # Get

  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 "dispatch()" method to run various actions.

      my $build = Module::Build->new
        (
         module_name => 'Foo::Bar',
         license     => 'perl',
         requires    => { 'Some::Module'   => '1.23' },
        );
      $build->dispatch('build');
      $build->dispatch('test', verbose => 1);
      $build->dispatch('install');

    The first argument to "dispatch()" 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 "rpm" or Debian's
    "deb", you may need to install to a temporary directory first and then
    create the package from that temporary installation. To do this, specify
    the "destdir" parameter to the "install" action:

      ./Build install --destdir /tmp/my-package-1.003

    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
    "install_base" or "prefix" parameters:

      ./Build install --install_base /foo/bar

    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 "--prefix" in Module::Build 0.28 and
    "INSTALL_BASE" in "ExtUtils::MakeMaker" 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 "ExtUtils::MakeMaker". Prior versions have differing (and in
    some cases quite strange) installation behaviors.

    The following installation flags are equivalent between
    "ExtUtils::MakeMaker" and "Module::Build".

        MakeMaker             Module::Build
        PREFIX=...            --prefix ...
        INSTALL_BASE=...      --install_base ...
        DESTDIR=...           --destdir ...
        LIB=...               --install_path lib=...
        INSTALLDIRS=...       --installdirs ...
        INSTALLDIRS=perl      --installdirs core
        UNINST=...            --uninst ...
        INC=...               --extra_compiler_flags ...
        POLLUTE=1             --extra_compiler_flags -DPERL_POLLUTE

    For example, if you are currently installing "MakeMaker" modules with
    this command:

        perl Makefile.PL PREFIX=~
        make test
        make install UNINST=1

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

        perl Build.PL --prefix ~
        ./Build test
        ./Build install --uninst 1

   "prefix" vs "install_base"
    The behavior of "prefix" 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 "prefix" will place
    your modules.

    In contrast, "install_base" has predictable, easy to explain
    installation locations. Now that "Module::Build" and "MakeMaker" both
    have "install_base" there is little reason to use "prefix" other than to
    preserve your existing installation locations. If you are starting a
    fresh Perl installation we encourage you to use "install_base". If you
    have an existing installation installed via "prefix", consider moving it
    to an installation structure matching "install_base" and using that
    instead.

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

      ./Build test --test_files t/mytest.t

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

      ./Build test --test_files t/mytest.t --verbose 1

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

      alias t './Build test --verbose 1 --test_files'

    So then I can just execute "t t/mytest.t" 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 "create_makefile_pl" parameter to
    "Module::Build->new()" in the "Build.PL" script, which can create
    various flavors of Makefile.PL during the "dist" 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::Build::Compat" module, which is part of "Module::Build"'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 "build_elements" property specifies the steps "Module::Build" will
    take when building a distribution. To change the build order, change the
    order of the entries in that property:

      # Process pod files first
      my @e = @{$build->build_elements};
      my ($i) = grep {$e[$_] eq 'pod'} 0..$#e;
      unshift @e, splice @e, $i, 1;

    Currently, "build_elements" has the following default value:

      [qw( PL support pm xs pod script )]

    Do take care when altering this property, since there may be non-obvious
    (and non-documented!) ordering dependencies in the "Module::Build" 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 "Foo::Bar"
    module and you'd like for it to end up as Foo/Bar.dat somewhere in
    perl's @INC path so "Foo::Bar" can access it easily at runtime. The
    following code from a sample "Build.PL" file demonstrates how to
    accomplish this:

      use Module::Build;
      my $build = Module::Build->new
        (
         module_name => 'Foo::Bar',
         ...other stuff here...
        );
      $build->add_build_element('dat');
      $build->create_build_script;

    This will find all .dat files in the lib/ directory, copy them to the
    blib/lib/ directory during the "build" action, and install them during
    the "install" action.

    If your extra files aren't located in the "lib/" directory in your
    distribution, you can explicitly say where they are, just as you'd do
    with .pm or .pod files:

      use Module::Build;
      my $build = new Module::Build
        (
         module_name => 'Foo::Bar',
         dat_files => {'some/dir/Bar.dat' => 'lib/Foo/Bar.dat'},
         ...other stuff here...
        );
      $build->add_build_element('dat');
      $build->create_build_script;

    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 "Module::Build" and create a special method to process
    them, named "process_${kind}_files()":

      use Module::Build;
      my $class = Module::Build->subclass(code => <<'EOF');
        sub process_dat_files {
          my $self = shift;
          ... locate and process *.dat files,
          ... and create something in blib/lib/
        }
      EOF
      my $build = $class->new
        (
         module_name => 'Foo::Bar',
         ...other stuff here...
        );
      $build->add_build_element('dat');
      $build->create_build_script;

    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 "install" action (see
    "INSTALL PATHS" in Module::Build.

    If you need to create a new custom type of installable element, e.g.
    "conf", then you need to tell Module::Build where things in blib/conf/
    should be installed. To do this, use the "install_path" parameter to the
    "new()" method:

      my $build = Module::Build->new
        (
         ...other stuff here...
         install_path => { conf => $installation_path }
        );

    Or you can call the "install_path()" method later:

      $build->install_path(conf => $installation_path);

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

      perl Build.PL --install_path conf=/foo/path/etc

    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 "install" 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 "SVN-Notify-Mirror" 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 "./Build install", 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 "Module::Build" on the fly using the "subclass()"
    method and override the methods that perform the actions. You may need
    to read through "Module::Build::Authoring" and "Module::Build::API" 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 "install" action:

      # Build.PL
      use Module::Build;
      my $class = Module::Build->subclass(
          class => "Module::Build::Custom",
          code => <<'SUBCLASS' );

      sub ACTION_install {
          my $self = shift;
          # YOUR CODE HERE
          $self->SUPER::ACTION_install;
      }
      SUBCLASS

      $class->new(
          module_name => 'Your::Module',
          # rest of the usual Module::Build parameters
      )->create_build_script;

  Adding an action
    You can add a new "./Build" action simply by writing the method for it
    in your subclass. Use "depends_on" to declare that another action must
    have been run before your action.

    For example, let's say you wanted to be able to write "./Build commit"
    to test your code and commit it to Subversion.

      # Build.PL
      use Module::Build;
      my $class = Module::Build->subclass(
          class => "Module::Build::Custom",
          code => <<'SUBCLASS' );

      sub ACTION_commit {
          my $self = shift;

          $self->depends_on("test");
          $self->do_system(qw(svn commit));
      }
      SUBCLASS

  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
    "configure_requires" to your minimum version of Module::Build. See
    Module::Build::Authoring.

    But not every build system honors "configure_requires" 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.

        cd Module-Build
        perl Build.PL --install_base /path/to/Your-Project/inc/Module-Build
        ./Build test
        ./Build install

    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.

        my $Bundled_MB = 0.30;  # or whatever version it was.

        # Find out what version of Module::Build is installed or fail quietly.
        # This should be cross-platform.
        my $Installed_MB =
            `$^X -e "eval q{require Module::Build; print Module::Build->VERSION} or exit 1"`;

        # some operating systems put a newline at the end of every print.
        chomp $Installed_MB;

        $Installed_MB = 0 if $?;

        # Use our bundled copy of Module::Build if it's newer than the installed.
        unshift @INC, "inc/Module-Build/lib/perl5" if $Bundled_MB > $Installed_MB;

        require Module::Build;

    And write the rest of your Build.PL normally. Module::Build will
    remember your change to @INC and use it when you run ./Build.

    In the future, we hope to provide a more automated solution for this
    scenario; see "inc/latest.pm" in the Module::Build distribution for one
    indication of the direction we're moving.

AUTHOR
    Ken Williams <kwilliams AT cpan.org>

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)