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Module::Build::Cookbook - Examples of Module::Build Usage |
Module::Build::Cookbook - Examples of Module::Build Usage
Module::Build isn't conceptually very complicated, but examples are
always helpful. I got the idea for writing this cookbook when
attending Brian Ingerson's ``Extreme Programming Tools for Module
Authors'' presentation at YAPC 2003, when he said, straightforwardly,
``Write A Cookbook.''
The definitional of how stuff works is in the main Module::Build
documentation. It's best to get familiar with that too.
In most cases, you can just issue the following commands from your shell:
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. If you know how to do that on your system, you can get installation working.
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
The Build script knows what perl was used to run Build.PL, so
you don't need to reinvoke the Build script with the complete perl
path each time. If you invoke it with the wrong perl path, you'll
get a warning.
If the current directory (usually called '.') isn't in your path, you
can do ./Build or perl Build to run the script:
/usr/bin/perl Build.PL ./Build ./Build test ./Build install
New versions of CPAN.pm understand how to use a Build.PL script, but old versions don't. If you want to help users who have old versions, do the following:
Create a file in your distribution named Makefile.PL, with the following contents:
use Module::Build::Compat; Module::Build::Compat->run_build_pl(args => \@ARGV); Module::Build::Compat->write_makefile();
Now CPAN will work as usual, ie: `perl Makefile.PL`, `make`, `make test`, and `make install`.
Alternatively, see the create_makefile_pl parameter to the <
Module::Build-new() >> method.
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 $b = Module::Build->new(
module_name => 'Foo::Bar',
license => 'perl',
requires => { 'Some::Module' => '1.23' },
);
$b->dispatch('build');
$b->dispatch('test', verbose => 1);
$b->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.
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
Module::Builde 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 actually 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.
If there's some new type of file (i.e. not a .pm file, or .xs
file, or one of the other things Module::Build knows how to
process) that you'd like to handle during the building of your module,
you can do something the following in your Build.PL file:
use Module::Build;
my $class = Module::Build->subclass( code => <<'EOC' );
sub process_foo_files {
my $self = shift;
... locate and process foo files, and create something in blib/
}
}
my $build = $class->new( ... );
$build->add_build_element('foo');
This creates a custom subclass of Module::Build that knows how to
build elements of type foo. It should place the elements in a
subdirectory of blib/ corresponding to items that Module::Build
knows how to install - to add new capabilities in that arena, see
Adding new types to the install process.
The build_elements property specifies the steps Module::Build
will take when building a distribution. To change the build order,
change the order of the entries in that property:
# Process pod files first
my @e = @{$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.
If you have more than one perl interpreter installed on your
system, you can choose which installation to target whenever you use
Module::Build. Usually it's as simple as using the right perl
in the perl Build.PL step - this perl will be remembered for the
rest of the life of the generated Build script.
Occasionally, however, we get it wrong. This is because there often
is no reliable way in perl to find a path to the currently-running
perl interpreter. When $^X doesn't tell us much (e.g. when it's
something like ``perl'' instead of an absolute path), we do some very
effective guessing, but there's still a small chance we can get it
wrong. Or not find one at all.
Therefore, if you want to explicitly tell Module::Build which perl
binary you're targetting, you can override $Config{perlpath}, like
so:
/foo/perl Build.PL --config perlpath=/foo/perl ./Build --config perlpath=/foo/perl ./Build test --config perlpath=/foo/perl
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 Foo.dat file containing some data
related to the Boo::Baz module. Assuming the data doesn't need to
be created on the fly, the best place for it to end up is probably as
Boo/Baz/Foo.dat somewhere in perl's @INC path so Boo::Baz 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 = new Module::Build
(
module_name => 'Boo::Baz',
...
);
$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 in the lib/ directory, 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 => 'Boo::Baz',
dat_files => {'some/dir/Foo.dat' => 'lib/Boo/Baz/Foo.dat'},
...
);
$build->add_build_element('dat');
$build->create_build_script;
If your extra files actually need to be created on the user's machine,
you'll probably have to override the build action to do so:
use Module::Build;
my $class = Module::Build->subclass(code => <<'EOF');
sub ACTION_build {
my $self = shift;
$self->SUPER::ACTION_build(@_);
... create the .dat files here ...
}
EOF
my $build = $class->new
(
module_name => 'Boo::Baz',
...
);
$build->add_build_element('dat');
$build->create_build_script;
Please note that these examples use some capabilities of Module::Build that first appeared in version 0.26. Before that it could certainly still be done, but the simple cases took a bit more work.
Ken Williams, ken@mathforum.org
perl(1), Module::Build(3)
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Module::Build::Cookbook - Examples of Module::Build Usage |