| Module::Build::API - API Reference for Module Authors |
Module::Build::API - API Reference for Module Authors
I list here some of the most important methods in Module::Build.
Normally you won't need to deal with these methods unless you want to
subclass Module::Build. But since one of the reasons I created
this module in the first place was so that subclassing is possible
(and easy), I will certainly write more docs as the interface
stabilizes.
current()This method returns a reasonable facsimile of the currently-executing
Module::Build object representing the current build. You can use
this object to query its notes() method, inquire about installed
modules, and so on. This is a great way to share information between
different parts of your build process. For instance, you can ask
the user a question during perl Build.PL, then use their answer
during a regression test:
# In Build.PL:
my $color = $build->prompt("What is your favorite color?");
$build->notes(color => $color);
# In t/colortest.t:
use Module::Build;
my $build = Module::Build->current;
my $color = $build->notes('color');
...
The way the current() method is currently implemented, there may be
slight differences between the $build object in Build.PL and the
one in t/colortest.t. It is our goal to minimize these differences
in future releases of Module::Build, so please report any anomalies
you find.
One important caveat: in its current implementation, current() will
NOT work correctly if you have changed out of the directory that
Module::Build was invoked from.
new()Creates a new Module::Build object. Arguments to the new() method are
listed below. Most arguments are optional, but you must provide
either the module_name argument, or dist_name and one of
dist_version or dist_version_from. In other words, you must
provide enough information to determine both a distribution name and
version.
An array reference of files to be cleaned up when the clean action
is performed. See also the add_to_cleanup()
method.
A bool indicating the module is still functional without its xs parts. When an XS module is build with --pureperl_only, it will otherwise fail.
This parameter determines whether Module::Build will add itself automatically to configure_requires (and build_requires) if Module::Build is not already there. The required version will be the last 'major' release, as defined by the decimal version truncated to two decimal places (e.g. 0.34, instead of 0.3402). The default value is true.
This parameter supports the setting of features (see
feature($name)) automatically based on a set of prerequisites. For
instance, for a module that could optionally use either MySQL or
PostgreSQL databases, you might use auto_features like this:
my $build = Module::Build->new
(
...other stuff here...
auto_features => {
pg_support => {
description => "Interface with Postgres databases",
requires => { 'DBD::Pg' => 23.3,
'DateTime::Format::Pg' => 0 },
},
mysql_support => {
description => "Interface with MySQL databases",
requires => { 'DBD::mysql' => 17.9,
'DateTime::Format::MySQL' => 0 },
},
}
);
For each feature named, the required prerequisites will be checked, and
if there are no failures, the feature will be enabled (set to 1).
Otherwise the failures will be displayed to the user and the feature
will be disabled (set to 0).
See the documentation for requires for the details of how requirements can be specified.
An optional autosplit argument specifies a file which should be run
through the AutoSplit::autosplit() function.
If multiple files should be split, the argument may be given as an
array of the files to split.
In general I don't consider autosplitting a great idea, because it's not always clear that autosplitting achieves its intended performance benefits. It may even harm performance in environments like mod_perl, where as much as possible of a module's code should be loaded during startup.
The Module::Build class or subclass to use in the build script.
Defaults to ``Module::Build'' or the class name passed to or created by
a call to subclass(). This property is useful if you're
writing a custom Module::Build subclass and have a bootstrapping
problem--that is, your subclass requires modules that may not be
installed when perl Build.PL is executed, but you've listed in
build_requires so that they should be available when ./Build is
executed.
Modules listed in this section are necessary to build and install the given module, but are not necessary for regular usage of it. This is actually an important distinction - it allows for tighter control over the body of installed modules, and facilitates correct dependency checking on binary/packaged distributions of the module.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
Modules listed in this section must be installed before configuring
this distribution (i.e. before running the Build.PL script).
This might be a specific minimum version of Module::Build or any
other module the Build.PL needs in order to do its stuff. Clients
like CPAN.pm or CPANPLUS will be expected to pick
configure_requires out of the META.yml file and install these
items before running the Build.PL.
Module::Build may automatically add itself to configure_requires. See auto_configure_requires for details.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
Modules listed in this section must be installed before testing the distribution.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
If true, this parameter tells Module::Build to create a .packlist
file during the install action, just like ExtUtils::MakeMaker does.
The file is created in a subdirectory of the arch installation
location. It is used by some other tools (CPAN, CPANPLUS, etc.) for
determining what files are part of an install.
The default value is true. This parameter was introduced in Module::Build version 0.2609; previously no packlists were ever created by Module::Build.
An optional c_source argument specifies a directory which contains
C source files that the rest of the build may depend on. Any .c
files in the directory will be compiled to object files. The
directory will be added to the search path during the compilation and
linking phases of any C or XS files.
[version 0.3604]
A list of directories can be supplied using an anonymous array reference of strings.
Modules listed in this section conflict in some serious way with the
given module. Module::Build (or some higher-level tool) will
refuse to install the given module if the given module/version is also
installed.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
This parameter tells Module::Build to automatically create a
LICENSE file at the top level of your distribution, containing the
full text of the author's chosen license. This requires
Software::License on the author's machine, and further requires
that the license parameter specifies a license that it knows about.
This parameter lets you use Module::Build::Compat during the
distdir (or dist) action to automatically create a Makefile.PL
for compatibility with ExtUtils::MakeMaker. The parameter's value
should be one of the styles named in the the Module::Build::Compat manpage
documentation.
This parameter tells Module::Build to automatically create a README
file at the top level of your distribution. Currently it will simply
use Pod::Text (or Pod::Readme if it's installed) on the file
indicated by dist_version_from and put the result in the README
file. This is by no means the only recommended style for writing a
README, but it seems to be one common one used on the CPAN.
If you generate a README in this way, it's probably a good idea to create a separate INSTALL file if that information isn't in the generated README.
This should be a short description of the distribution. This is used when
generating metadata for META.yml and PPD files. If it is not given
then Module::Build looks in the POD of the module from which it gets
the distribution's version. If it finds a POD section marked ``=head1
NAME'', then it looks for the first line matching \s+-\s+(.+),
and uses the captured text as the abstract.
This should be something like ``John Doe <jdoe@example.com>'', or if
there are multiple authors, an anonymous array of strings may be
specified. This is used when generating metadata for META.yml and
PPD files. If this is not specified, then Module::Build looks at
the module from which it gets the distribution's version. If it finds
a POD section marked ``=head1 AUTHOR'', then it uses the contents of
this section.
Specifies the name for this distribution. Most authors won't need to
set this directly, they can use module_name to set dist_name to
a reasonable default. However, some agglomerative distributions like
libwww-perl or bioperl have names that don't correspond directly
to a module name, so dist_name can be set independently.
Specifies an optional suffix to include after the version number in the distribution directory (and tarball) name. The only suffix currently recognized by PAUSE is 'TRIAL', which indicates that the distribution should not be indexed. For example:
Foo-Bar-1.23-TRIAL.tar.gz
This will automatically do the ``right thing'' depending on dist_version and
release_status. When dist_version does not have an underscore and
release_status is not 'stable', then dist_suffix will default to 'TRIAL'.
Otherwise it will default to the empty string, disabling the suffix.
In general, authors should only set this if they must override the default behavior for some particular purpose.
Specifies a version number for the distribution. See module_name
or dist_version_from for ways to have this set automatically from a
$VERSION variable in a module. One way or another, a version
number needs to be set.
Specifies a file to look for the distribution version in. Most authors won't need to set this directly, they can use module_name to set it to a reasonable default.
The version is extracted from the specified file according to the same
rules as the ExtUtils::MakeMaker manpage and CPAN.pm. It involves finding
the first line that matches the regular expression
/([\$*])(([\w\:\']*)\bVERSION)\b.*\=/
eval()-ing that line, then checking the value of the $VERSION
variable. Quite ugly, really, but all the modules on CPAN depend on
this process, so there's no real opportunity to change to something
better.
If the target file of dist_version_from contains more than one package declaration, the version returned will be the one matching the configured module_name.
A boolean flag indicating whether the Build.PL file must be executed to determine prerequisites, or whether they can be determined solely from consulting its metadata file. The main reason to set this to a true value is that your module adds or removes prerequisites dynamically in Build.PL. If the flag is omitted, it will be treated as 1 (true), because this is a safer way to behave.
Currently Module::Build doesn't actually do anything with this flag
- it's up to higher-level tools like CPAN.pm to do something useful
with it. It can also be very helpful for static analysis. See
dynamic_config in the CPAN::Meta::Spec manpage for details on the metadata field.
These parameters can contain array references (or strings, in which case they will be split into arrays) to pass through to the compiler and linker phases when compiling/linking C code. For example, to tell the compiler that your code is C++, you might do:
my $build = Module::Build->new
(
module_name => 'Foo::Bar',
extra_compiler_flags => ['-x', 'c++'],
);
To link your XS code against glib you might write something like:
my $build = Module::Build->new
(
module_name => 'Foo::Bar',
dynamic_config => 1,
extra_compiler_flags => scalar `glib-config --cflags`,
extra_linker_flags => scalar `glib-config --libs`,
);
Any extra arguments to pass to Pod::Man->new() when building
man pages. One common choice might be utf8 => 1 to get Unicode
support.
You can pass arbitrary command line options to Build.PL or
Build, and they will be stored in the Module::Build object and can
be accessed via the args() method. However, sometimes you want
more flexibility out of your argument processing than this allows. In
such cases, use the get_options parameter to pass in a hash
reference of argument specifications, and the list of arguments to
Build.PL or Build will be processed according to those
specifications before they're passed on to Module::Build's own
argument processing.
The supported option specification hash keys are:
=s for strings,
+ for additive options, and ! for negatable options. If the
type is not specified, it will be considered a boolean, i.e. no
argument is taken and a value of 1 will be assigned when the option is
encountered.
args() method.
args().
You can combine references to your own variables or subroutines with
unreferenced specifications, for which the result will also be stored in the
hash returned by args(). For example:
my $loud = 0;
my $build = Module::Build->new
(
module_name => 'Foo::Bar',
get_options => {
Loud => { store => \$loud },
Dbd => { type => '=s' },
Quantity => { type => '+' },
}
);
print STDERR "HEY, ARE YOU LISTENING??\n" if $loud;
print "We'll use the ", $build->args('Dbd'), " DBI driver\n";
print "Are you sure you want that many?\n"
if $build->args('Quantity') > 2;
The arguments for such a specification can be called like so:
perl Build.PL --Loud --Dbd=DBD::pg --Quantity --Quantity --Quantity
WARNING: Any option specifications that conflict with Module::Build's own options (defined by its properties) will throw an exception. Use capitalized option names to avoid unintended conflicts with future Module::Build options.
Consult the Getopt::Long documentation for details on its usage.
Specifies any additional directories in which to search for C header files. May be given as a string indicating a single directory, or as a list reference indicating multiple directories.
You can set paths for individual installable elements by using the
install_path parameter:
my $build = Module::Build->new
(
...other stuff here...
install_path => {
lib => '/foo/lib',
arch => '/foo/lib/arch',
}
);
Determines where files are installed within the normal perl hierarchy
as determined by Config.pm. Valid values are: core, site,
vendor. The default is site. See
INSTALL PATHS in the Module::Build manpage
Specifies the licensing terms of your distribution.
As of Module::Build version 0.36_14, you may use a the Software::License manpage subclass name (e.g. 'Apache_2_0') instead of one of the keys below.
The legacy list of valid license values include:
Note that you must still include the terms of your license in your code and documentation - this field only sets the information that is included in distribution metadata to let automated tools figure out your licensing restrictions. Humans still need something to read. If you choose to provide this field, you should make sure that you keep it in sync with your written documentation if you ever change your licensing terms.
You may also use a license type of unknown if you don't wish to
specify your terms in the metadata.
Also see the create_license parameter.
A hash of key/value pairs that should be added to the META.yml file
during the distmeta action. Any existing entries with the same
names will be overridden.
See the MODULE METADATA section for details.
A hash of key/value pairs that should be merged into the META.yml
file during the distmeta action. Any existing entries with the
same names will be overridden.
The only difference between meta_add and meta_merge is their
behavior on hash-valued and array-valued entries: meta_add will
completely blow away the existing hash or array value, but
meta_merge will merge the supplied data into the existing hash or
array value.
See the MODULE METADATA section for details.
The module_name is a shortcut for setting default values of
dist_name and dist_version_from, reflecting the fact that the
majority of CPAN distributions are centered around one ``main'' module.
For instance, if you set module_name to Foo::Bar, then
dist_name will default to Foo-Bar and dist_version_from will
default to lib/Foo/Bar.pm. dist_version_from will in turn be
used to set dist_version.
Setting module_name won't override a dist_* parameter you
specify explicitly.
The needs_compiler parameter indicates whether a compiler is required to
build the distribution. The default is false, unless XS files are found or
the c_source parameter is set, in which case it is true. If true,
the ExtUtils::CBuilder manpage is automatically added to build_requires if needed.
For a distribution where a compiler is optional, e.g. a dual XS/pure-Perl
distribution, needs_compiler should explicitly be set to a false value.
An optional parameter specifying a set of .PL files in your
distribution. These will be run as Perl scripts prior to processing
the rest of the files in your distribution with the name of the file
they're generating as an argument. They are usually used as templates
for creating other files dynamically, so that a file like
lib/Foo/Bar.pm.PL might create the file lib/Foo/Bar.pm.
The files are specified with the .PL files as hash keys, and the
file(s) they generate as hash values, like so:
my $build = Module::Build->new
(
module_name => 'Foo::Bar',
...
PL_files => { 'lib/Foo/Bar.pm.PL' => 'lib/Foo/Bar.pm' },
);
Note that the path specifications are always given in Unix-like format, not in the style of the local system.
If your .PL scripts don't create any files, or if they create files
with unexpected names, or even if they create multiple files, you can
indicate that so that Module::Build can properly handle these created
files:
PL_files => {
'lib/Foo/Bar.pm.PL' => 'lib/Foo/Bar.pm',
'lib/something.PL' => ['/lib/something', '/lib/else'],
'lib/funny.PL' => [],
}
Here's an example of a simple PL file.
my $output_file = shift;
open my $fh, ">", $output_file or die "Can't open $output_file: $!";
print $fh <<'END';
#!/usr/bin/perl
print "Hello, world!\n";
END
PL files are not installed by default, so its safe to put them in lib/ and bin/.
An optional parameter specifying the set of .pm files in this
distribution, specified as a hash reference whose keys are the files'
locations in the distributions, and whose values are their logical
locations based on their package name, i.e. where they would be found
in a ``normal'' Module::Build-style distribution. This parameter is
mainly intended to support alternative layouts of files.
For instance, if you have an old-style MakeMaker distribution for a
module called Foo::Bar and a Bar.pm file at the top level of the
distribution, you could specify your layout in your Build.PL like
this:
my $build = Module::Build->new
(
module_name => 'Foo::Bar',
...
pm_files => { 'Bar.pm' => 'lib/Foo/Bar.pm' },
);
Note that the values should include lib/, because this is where
they would be found in a ``normal'' Module::Build-style distribution.
Note also that the path specifications are always given in Unix-like format, not in the style of the local system.
Just like pm_files, but used for specifying the set of .pod
files in your distribution.
This is just like the requires argument, except that modules listed in this section aren't essential, just a good idea. We'll just print a friendly warning if one of these modules aren't found, but we'll continue running.
If a module is recommended but not required, all tests should still pass if the module isn't installed. This may mean that some tests may be skipped if recommended dependencies aren't present.
Automated tools like CPAN.pm should inform the user when recommended modules aren't installed, and it should offer to install them if it wants to be helpful.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
Normally, Module::Build does not search subdirectories when looking
for tests to run. When this options is set it will search recursively
in all subdirectories of the standard 't' test directory.
The CPAN Meta Spec version 2 adds release_status to allow authors
to specify how a distribution should be indexed. Consistent with the
spec, this parameter can only have one three values: 'stable',
'testing' or 'unstable'.
Unless explicitly set by the author, release_status will default
to 'stable' unless dist_version contains an underscore, in which
case it will default to 'testing'.
It is an error to specify a release_status of 'stable' when
dist_version contains an underscore character.
An optional requires argument specifies any module prerequisites
that the current module depends on.
One note: currently Module::Build doesn't actually require the
user to have dependencies installed, it just strongly urges. In the
future we may require it. There's also a recommends section for
things that aren't absolutely required.
Automated tools like CPAN.pm should refuse to install a module if one of its dependencies isn't satisfied, unless a ``force'' command is given by the user. If the tools are helpful, they should also offer to install the dependencies.
A synonym for requires is prereq, to help succour people
transitioning from ExtUtils::MakeMaker. The requires term is
preferred, but the prereq term will remain valid in future
distributions.
See the documentation for PREREQUISITES in the Module::Build::Authoring manpage for the details of how requirements can be specified.
An optional parameter specifying a set of files that should be installed as executable Perl scripts when the module is installed. May be given as an array reference of the files, as a hash reference whose keys are the files (and whose values will currently be ignored), as a string giving the name of a directory in which to find scripts, or as a string giving the name of a single script file.
The default is to install any scripts found in a bin directory at the top level of the distribution, minus any keys of PL_files.
For backward compatibility, you may use the parameter scripts
instead of script_files. Please consider this usage deprecated,
though it will continue to exist for several version releases.
An optional parameter specifying directories of static data files to
be installed as read-only files for use with the File::ShareDir manpage. The
share_dir property supports both distribution-level and
module-level share files.
The simplest use of share_dir is to set it to a directory name or an
arrayref of directory names containing files to be installed in the
distribution-level share directory.
share_dir => 'share'
Alternatively, if share_dir is a hashref, it may have dist or
module keys providing full flexibility in defining how share
directories should be installed.
share_dir => {
dist => [ 'examples', 'more_examples' ],
module => {
Foo::Templates => ['share/html', 'share/text'],
Foo::Config => 'share/config',
}
}
If share_dir is set, then File::ShareDir will automatically be added
to the requires hash.
If a true value is specified for this parameter, the Module::Signature manpage will be used (via the 'distsign' action) to create a SIGNATURE file for your distribution during the 'distdir' action, and to add the SIGNATURE file to the MANIFEST (therefore, don't add it yourself).
The default value is false. In the future, the default may change to
true if you have Module::Signature installed on your system.
An optional parameter specifying parameters to be passed to TAP::Harness when
running tests. Must be given as a hash reference of parameters; see the
TAP::Harness documentation for details. Note that specifying
this parameter will implicitly set use_tap_harness to a true value. You
must therefore be sure to add TAP::Harness as a requirement for your module in
build_requires.
An optional parameter specifying a set of files that should be used as
Test::Harness-style regression tests to be run during the test
action. May be given as an array reference of the files, or as a hash
reference whose keys are the files (and whose values will currently be
ignored). If the argument is given as a single string (not in an
array reference), that string will be treated as a glob() pattern
specifying the files to use.
The default is to look for a test.pl script in the top-level
directory of the distribution, and any files matching the glob pattern
*.t in the t/ subdirectory. If the recursive_test_files
property is true, then the t/ directory will be scanned recursively
for *.t files.
An optional parameter indicating whether or not to use TAP::Harness for
testing rather than Test::Harness. Defaults to false. If set to true, you must
therefore be sure to add TAP::Harness as a requirement for your module in
build_requires. Implicitly set to a true value if tap_harness_args is
specified.
Just like pm_files, but used for specifying the set of .xs
files in your distribution.
new_from_context(%args)When called from a directory containing a Build.PL script (in other words,
the base directory of a distribution), this method will run the Build.PL and
call resume() to return the resulting Module::Build object to the caller.
Any key-value arguments given to new_from_context() are essentially like
command line arguments given to the Build.PL script, so for example you
could pass verbose => 1 to this method to turn on verbosity.
resume()You'll probably never call this method directly, it's only called from the
auto-generated Build script (and the new_from_context method). The
new() method is only called once, when the user runs perl Build.PL.
Thereafter, when the user runs Build test or another action, the
Module::Build object is created using the resume() method to
re-instantiate with the settings given earlier to new().
subclass()This creates a new Module::Build subclass on the fly, as described
in the SUBCLASSING in the Module::Build::Authoring manpage section. The caller
must provide either a class or code parameter, or both. The
class parameter indicates the name to use for the new subclass, and
defaults to MyModuleBuilder. The code parameter specifies Perl
code to use as the body of the subclass.
package 'My::Build';
use base 'Module::Build';
__PACKAGE__->add_property( 'pedantic' );
__PACKAGE__->add_property( answer => 42 );
__PACKAGE__->add_property(
'epoch',
default => sub { time },
check => sub {
return 1 if /^\d+$/;
shift->property_error( "'$_' is not an epoch time" );
return 0;
},
);
Adds a property to a Module::Build class. Properties are those attributes of a
Module::Build object which can be passed to the constructor and which have
accessors to get and set them. All of the core properties, such as
module_name and license, are defined using this class method.
The first argument to add_property() is always the name of the property.
The second argument can be either a default value for the property, or a list
of key/value pairs. The supported keys are:
default
default => sub { sub { ... } },
check$_ variable. If the value is correct, the check code reference
should return true. If the value is not correct, it sends an error message to
property_error() and returns false.
When this method is called, a new property will be installed in the Module::Build class, and an accessor will be built to allow the property to be get or set on the build object.
print $build->pedantic, $/; $build->pedantic(0);
If the default value is a hash reference, this generates a special-case accessor method, wherein individual key/value pairs may be set or fetched:
print "stuff{foo} is: ", $build->stuff( 'foo' ), $/;
$build->stuff( foo => 'bar' );
print $build->stuff( 'foo' ), $/; # Outputs "bar"
Of course, you can still set the entire hash reference at once, as well:
$build->stuff( { foo => 'bar', baz => 'yo' } );
In either case, if a check has been specified for the property, it will be
applied to the entire hash. So the check code reference should look something
like:
check => sub {
return 1 if defined $_ && exists $_->{foo};
shift->property_error(qq{Property "stuff" needs "foo"});
return 0;
},
add_build_element($type)Adds a new type of entry to the build process. Accepts a single
string specifying its type-name. There must also be a method defined
to process things of that type, e.g. if you add a build element called
'foo', then you must also define a method called
process_foo_files().
See also Adding new file types to the build process in the Module::Build::Cookbook manpage.
add_to_cleanup(@files)You may call $self->add_to_cleanup(@patterns) to tell
Module::Build that certain files should be removed when the user
performs the Build clean action. The arguments to the method are
patterns suitable for passing to Perl's glob() function, specified
in either Unix format or the current machine's native format. It's
usually convenient to use Unix format when you hard-code the filenames
(e.g. in Build.PL) and the native format when the names are
programmatically generated (e.g. in a testing script).
I decided to provide a dynamic method of the $build object, rather
than just use a static list of files named in the Build.PL, because
these static lists can get difficult to manage. I usually prefer to
keep the responsibility for registering temporary files close to the
code that creates them.
args()my $args_href = $build->args; my %args = $build->args; my $arg_value = $build->args($key); $build->args($key, $value);
This method is the preferred interface for retrieving the arguments passed via command line options to Build.PL or Build, minus the Module-Build specific options.
When called in a scalar context with no arguments, this method returns a reference to the hash storing all of the arguments; in an array context, it returns the hash itself. When passed a single argument, it returns the value stored in the args hash for that option key. When called with two arguments, the second argument is assigned to the args hash under the key passed as the first argument.
Invokes the the AutoSplit manpage module on the $from file, sending the
output to the lib/auto directory inside $to. $to is
typically the blib/ directory.
base_dir()Returns a string containing the root-level directory of this build,
i.e. where the Build.PL script and the lib directory can be
found. This is usually the same as the current working directory,
because the Build script will chdir() into this directory as
soon as it begins execution.
build_requires()Returns a hash reference indicating the build_requires
prerequisites that were passed to the new() method.
$action, or false
otherwise. This is handy for actions defined (or maybe not!) in subclasses.
[version 0.32_xx]
cbuilder()Returns the internal ExtUtils::CBuilder object that can be used for compiling & linking C code. If no such object is available (e.g. if the system has no compiler installed) an exception will be thrown.
This method returns a hash reference indicating whether a version
dependency on a certain module is satisfied. The $module argument
is given as a string like "Data::Dumper" or "perl", and the
$version argument can take any of the forms described in requires
above. This allows very fine-grained version checking.
The returned hash reference has the following structure:
{
ok => $whether_the_dependency_is_satisfied,
have => $version_already_installed,
need => $version_requested, # Same as incoming $version argument
message => $informative_error_message,
}
If no version of $module is currently installed, the have value
will be the string "<none>". Otherwise the have value will
simply be the version of the installed module. Note that this means
that if $module is installed but doesn't define a version number,
the have value will be undef - this is why we don't use undef
for the case when $module isn't installed at all.
This method may be called either as an object method
($build->check_installed_status($module, $version))
or as a class method
(Module::Build->check_installed_status($module, $version)).
Like check_installed_status(),
but simply returns true or false depending on whether module
$module satisfies the dependency $version.
If the check succeeds, the return value is the actual version of
$module installed on the system. This allows you to do the
following:
my $installed = $build->check_installed_version('DBI', '1.15');
if ($installed) {
print "Congratulations, version $installed of DBI is installed.\n";
} else {
die "Sorry, you must install DBI.\n";
}
If the check fails, we return false and set $@ to an informative
error message.
If $version is any non-true value (notably zero) and any version of
$module is installed, we return true. In this case, if $module
doesn't define a version, or if its version is zero, we return the
special value ``0 but true'', which is numerically zero, but logically
true.
In general you might prefer to use check_installed_status if you
need detailed information, or this method if you just need a yes/no
answer.
Compares two module versions $v1 and $v2 using the operator
$op, which should be one of Perl's numeric operators like != or
>= or the like. We do at least a halfway-decent job of
handling versions that aren't strictly numeric, like 0.27_02, but
exotic stuff will likely cause problems.
In the future, the guts of this method might be replaced with a call
out to version.pm.
config($key)config() [deprecated]With a single argument $key, returns the value associated with that
key in the Config.pm hash, including any changes the author or user
has specified.
With $key and $value arguments, sets the value for future
callers of config($key).
With no arguments, returns a hash reference containing all such key-value pairs. This usage is deprecated, though, because it's a resource hog and violates encapsulation.
config_data($name)With a single argument, returns the value of the configuration
variable $name. With two arguments, sets the given configuration
variable to the given value. The value may be any Perl scalar that's
serializable with Data::Dumper. For instance, if you write a
module that can use a MySQL or PostgreSQL back-end, you might create
configuration variables called mysql_connect and
postgres_connect, and set each to an array of connection parameters
for DBI->connect().
Configuration values set in this way using the Module::Build object
will be available for querying during the build/test process and after
installation via the generated ...::ConfigData module, as
...::ConfigData->config($name).
The feature() and config_data() methods represent
Module::Build's main support for configuration of installed modules.
See also SAVING CONFIGURATION INFORMATION in the Module::Build::Authoring manpage.
conflicts()Returns a hash reference indicating the conflicts prerequisites
that were passed to the new() method.
contains_pod($file) [deprecated][Deprecated] Please see the Module::Metadata manpage instead.
Returns true if the given file appears to contain POD documentation. Currently this checks whether the file has a line beginning with '=pod', '=head', or '=item', but the exact semantics may change in the future.
copy_if_modified(%parameters)Takes the file in the from parameter and copies it to the file in
the to parameter, or the directory in the to_dir parameter, if
the file has changed since it was last copied (or if it doesn't exist
in the new location). By default the entire directory structure of
from will be copied into to_dir; an optional flatten
parameter will copy into to_dir without doing so.
Returns the path to the destination file, or undef if nothing
needed to be copied.
Any directories that need to be created in order to perform the copying will be automatically created.
The destination file is set to read-only. If the source file has the executable bit set, then the destination file will be made executable.
create_build_script()Creates an executable script called Build in the current directory
that will be used to execute further user actions. This script is
roughly analogous (in function, not in form) to the Makefile created
by ExtUtils::MakeMaker. This method also creates some temporary
data in a directory called _build/. Both of these will be removed
when the realclean action is performed.
Among the files created in _build/ is a _build/prereqs file
containing the set of prerequisites for this distribution, as a hash
of hashes. This file may be eval()-ed to obtain the authoritative
set of prerequisites, which might be different from the contents of
META.yml (because Build.PL might have set them dynamically).
But fancy developers take heed: do not put any fancy custom runtime
code in the _build/prereqs file, leave it as a static declaration
containing only strings and numbers. Similarly, do not alter the
structure of the internal $self->{properties}{requires} (etc.)
data members, because that's where this data comes from.
current_action()Returns the name of the currently-running action, such as ``build'' or
``test''. This action is not necessarily the action that was originally
invoked by the user. For example, if the user invoked the ``test''
action, current_action() would initially return ``test''. However,
action ``test'' depends on action ``code'', so current_action() will
return ``code'' while that dependency is being executed. Once that
action has completed, current_action() will again return ``test''.
If you need to know the name of the original action invoked by the user, see invoked_action() below.
depends_on(@actions)Invokes the named action or list of actions in sequence. Using this method is preferred to calling the action explicitly because it performs some internal record-keeping, and it ensures that the same action is not invoked multiple times (note: in future versions of Module::Build it's conceivable that this run-only-once mechanism will be changed to something more intelligent).
Note that the name of this method is something of a misnomer; it
should really be called something like
invoke_actions_unless_already_invoked() or something, but for
better or worse (perhaps better!) we were still thinking in
make-like dependency terms when we created this method.
See also dispatch(). The main
distinction between the two is that depends_on() is meant to call
an action from inside another action, whereas dispatch() is meant
to set the very top action in motion.
Returns true if the first directory logically contains the second
directory. This is just a convenience function because File::Spec
doesn't really provide an easy way to figure this out (but
Path::Class does...).
Invokes the build action $action. Optionally, a list of options
and their values can be passed in. This is equivalent to invoking an
action at the command line, passing in a list of options.
Custom options that have not been registered must be passed in as a hash reference in a key named ``args'':
$build->dispatch('foo', verbose => 1, args => { my_option => 'value' });
This method is intended to be used to programmatically invoke build actions, e.g. by applications controlling Module::Build-based builds rather than by subclasses.
See also depends_on(). The main
distinction between the two is that depends_on() is meant to call
an action from inside another action, whereas dispatch() is meant
to set the very top action in motion.
dist_dir()Returns the name of the directory that will be created during the
dist action. The name is derived from the dist_name and
dist_version properties.
dist_name()Returns the name of the current distribution, as passed to the
new() method in a dist_name or modified module_name
parameter.
dist_version()Returns the version of the current distribution, as determined by the
new() method from a dist_version, dist_version_from, or
module_name parameter.
This is a fairly simple wrapper around Perl's system() built-in
command. Given a command and an array of optional arguments, this
method will print the command to STDOUT, and then execute it using
Perl's system(). It returns true or false to indicate success or
failure (the opposite of how system() works, but more intuitive).
Note that if you supply a single argument to do_system(), it
will/may be processed by the system's shell, and any special
characters will do their special things. If you supply multiple
arguments, no shell will get involved and the command will be executed
directly.
extra_compiler_flags()extra_compiler_flags(@flags)Set or retrieve the extra compiler flags. Returns an arrayref of flags.
extra_linker_flags()extra_linker_flags(@flags)Set or retrieve the extra linker flags. Returns an arrayref of flags.
feature($name)With a single argument, returns true if the given feature is set.
With two arguments, sets the given feature to the given boolean value.
In this context, a ``feature'' is any optional functionality of an
installed module. For instance, if you write a module that could
optionally support a MySQL or PostgreSQL backend, you might create
features called mysql_support and postgres_support, and set them
to true/false depending on whether the user has the proper databases
installed and configured.
Features set in this way using the Module::Build object will be
available for querying during the build/test process and after
installation via the generated ...::ConfigData module, as
...::ConfigData->feature($name).
The feature() and config_data() methods represent
Module::Build's main support for configuration of installed modules.
See also SAVING CONFIGURATION INFORMATION in the Module::Build::Authoring manpage.
fix_shebang_line(@files)Modify any ``shebang'' line in the specified files to use the path to the
perl executable being used for the current build. Files are modified
in-place. The existing shebang line must have a command that contains
``perl''; arguments to the command do not count. In particular, this
means that the use of #!/usr/bin/env perl will not be changed.
For an explanation of shebang lines, see http://en.wikipedia.org/wiki/Shebang_%28Unix%29.
have_c_compiler()Returns true if the current system seems to have a working C compiler. We currently determine this by attempting to compile a simple C source file and reporting whether the attempt was successful.
install_base_relpaths()install_base_relpaths($type)Set or retrieve the relative paths that are appended to
install_base for any installable element. This is useful if you
want to set the relative install path for custom build elements.
With no argument, it returns a reference to a hash containing all elements and their respective values. This hash should not be modified directly; use the multiple argument below form to change values.
The single argument form returns the value associated with the
element $type.
The multiple argument form allows you to set the paths for element types.
$value must be a relative path using Unix-like paths. (A series of
directories separated by slashes, e.g. foo/bar.) The return value is a
localized path based on $value.
Assigning the value undef to an element causes it to be removed.
install_destination($type)Returns the directory in which items of type $type (e.g. lib,
arch, bin, or anything else returned by the install_types()
method) will be installed during the install action. Any settings
for install_path, install_base, and prefix are taken into
account when determining the return value.
install_path()install_path($type)Set or retrieve paths for specific installable elements. This is
useful when you want to examine any explicit install paths specified
by the user on the command line, or if you want to set the install
path for a specific installable element based on another attribute
like install_base().
With no argument, it returns a reference to a hash containing all elements and their respective values. This hash should not be modified directly; use the multiple argument below form to change values.
The single argument form returns the value associated with the
element $type.
The multiple argument form allows you to set the paths for element types.
The supplied $path should be an absolute path to install elements
of $type. The return value is $path.
Assigning the value undef to an element causes it to be removed.
install_types()Returns a list of installable types that this build knows about.
These types each correspond to the name of a directory in blib/,
and the list usually includes items such as lib, arch, bin,
script, libdoc, bindoc, and if HTML documentation is to be
built, libhtml and binhtml. Other user-defined types may also
exist.
invoked_action()This is the name of the original action invoked by the user. This value is set when the user invokes Build.PL, the Build script, or programmatically through the dispatch() method. It does not change as sub-actions are executed as dependencies are evaluated.
To get the name of the currently executing dependency, see current_action() above.
notes()notes($key)The notes() value allows you to store your own persistent
information about the build, and to share that information among
different entities involved in the build. See the example in the
current() method.
The notes() method is essentially a glorified hash access. With no
arguments, notes() returns the entire hash of notes. With one argument,
notes($key) returns the value associated with the given key. With two
arguments, notes($key, $value) sets the value associated with the given key
to $value and returns the new value.
The lifetime of the notes data is for ``a build'' - that is, the
notes hash is created when perl Build.PL is run (or when the
new() method is run, if the Module::Build Perl API is being used
instead of called from a shell), and lasts until perl Build.PL is
run again or the clean action is run.
orig_dir()Returns a string containing the working directory that was in effect
before the Build script chdir()-ed into the base_dir. This
might be useful for writing wrapper tools that might need to chdir()
back out.
os_type()If you're subclassing Module::Build and some code needs to alter its
behavior based on the current platform, you may only need to know
whether you're running on Windows, Unix, MacOS, VMS, etc., and not the
fine-grained value of Perl's $^O variable. The os_type() method
will return a string like Windows, Unix, MacOS, VMS, or
whatever is appropriate. If you're running on an unknown platform, it
will return undef - there shouldn't be many unknown platforms
though.
is_vmsish()is_windowsish()is_unixish()prefix_relpaths()prefix_relpaths($installdirs)Set or retrieve the relative paths that are appended to prefix for
any installable element. This is useful if you want to set the
relative install path for custom build elements.
With no argument, it returns a reference to a hash containing all
elements and their respective values as defined by the current
installdirs setting.
With a single argument, it returns a reference to a hash containing
all elements and their respective values as defined by
$installdirs.
The hash returned by the above calls should not be modified directly; use the three-argument below form to change values.
The two argument form returns the value associated with the
element $type.
The multiple argument form allows you to set the paths for element types.
$value must be a relative path using Unix-like paths. (A series of
directories separated by slashes, e.g. foo/bar.) The return value is a
localized path based on $value.
Assigning the value undef to an element causes it to be removed.
get_metadata()This method returns a hash reference of metadata that can be used to create a YAML datastream. It is provided for authors to override or customize the fields of META.yml. E.g.
package My::Builder; use base 'Module::Build';
sub get_metadata {
my $self, @args = @_;
my $data = $self->SUPER::get_metadata(@args);
$data->{custom_field} = 'foo';
return $data;
}
Valid arguments include:
fatal -- indicates whether missing required
metadata fields should be a fatal error or not. For META creation, it
generally should, but for MYMETA creation for end-users, it should not be
fatal.
auto -- indicates whether any necessary configure_requires should be
automatically added. This is used in META creation.
This method is a wrapper around the old prepare_metadata API now that we no longer use YAML::Node to hold metadata.
prepare_metadata() [deprecated][Deprecated] As of 0.36, authors should use get_metadata instead. This
method is preserved for backwards compatibility only.
It takes three positional arguments: a hashref (to which metadata will be added), an optional arrayref (to which metadata keys will be added in order if the arrayref exists), and a hashref of arguments (as provided to get_metadata). The latter argument is new as of 0.36. Earlier versions are always fatal on errors.
Prior to version 0.36, this method took a YAML::Node as an argument to hold assembled metadata.
prereq_failures()Returns a data structure containing information about any failed
prerequisites (of any of the types described above), or undef if
all prerequisites are met.
The data structure returned is a hash reference. The top level keys are the type of prerequisite failed, one of ``requires'', ``build_requires'', ``conflicts'', or ``recommends''. The associated values are hash references whose keys are the names of required (or conflicting) modules. The associated values of those are hash references indicating some information about the failure. For example:
{
have => '0.42',
need => '0.59',
message => 'Version 0.42 is installed, but we need version 0.59',
}
or
{
have => '<none>',
need => '0.59',
message => 'Prerequisite Foo isn't installed',
}
This hash has the same structure as the hash returned by the
check_installed_status() method, except that in the case of
``conflicts'' dependencies we change the ``need'' key to ``conflicts'' and
construct a proper message.
Examples:
# Check a required dependency on Foo::Bar
if ( $build->prereq_failures->{requires}{Foo::Bar} ) { ...
# Check whether there were any failures
if ( $build->prereq_failures ) { ...
# Show messages for all failures
my $failures = $build->prereq_failures;
while (my ($type, $list) = each %$failures) {
while (my ($name, $hash) = each %$list) {
print "Failure for $name: $hash->{message}\n";
}
}
prereq_data()Returns a reference to a hash describing all prerequisites. The keys of the
hash will be the various prerequisite types ('requires', 'build_requires',
'test_requires', 'configure_requires', 'recommends', or 'conflicts') and the values will be
references to hashes of module names and version numbers. Only prerequisites
types that are defined will be included. The prereq_data action is just a
thin wrapper around the prereq_data() method and dumps the hash as a string
that can be loaded using eval().
prereq_report()Returns a human-readable (table-form) string showing all
prerequisites, the versions required, and the versions actually
installed. This can be useful for reviewing the configuration of your
system prior to a build, or when compiling data to send for a bug
report. The prereq_report action is just a thin wrapper around the
prereq_report() method.
Asks the user a question and returns their response as a string. The
first argument specifies the message to display to the user (for
example, "Where do you keep your money?"). The second argument,
which is optional, specifies a default answer (for example,
"wallet"). The user will be asked the question once.
If prompt() detects that it is not running interactively and there
is nothing on STDIN or if the PERL_MM_USE_DEFAULT environment variable
is set to true, the $default will be used without prompting.
To prevent automated processes from blocking, the user must either set PERL_MM_USE_DEFAULT or attach something to STDIN (this can be a pipe/file containing a scripted set of answers or /dev/null.)
If no $default is provided an empty string will be used instead. In
non-interactive mode, the absence of $default is an error (though
explicitly passing undef() as the default is valid as of 0.27.)
This method may be called as a class or object method.
recommends()Returns a hash reference indicating the recommends prerequisites
that were passed to the new() method.
requires()Returns a hash reference indicating the requires prerequisites that
were passed to the new() method.
Uses File::Find to traverse the directory $dir, returning a
reference to an array of entries matching $pattern. $pattern
may either be a regular expression (using qr// or just a plain
string), or a reference to a subroutine that will return true for
wanted entries. If $pattern is not given, all entries will be
returned.
Examples:
# All the *.pm files in lib/
$m->rscan_dir('lib', qr/\.pm$/)
# All the files in blib/ that aren't *.html files
$m->rscan_dir('blib', sub {-f $_ and not /\.html$/});
# All the files in t/
$m->rscan_dir('t');
runtime_params()runtime_params($key)The runtime_params() method stores the values passed on the command line
for valid properties (that is, any command line options for which
valid_property() returns a true value). The value on the command line may
override the default value for a property, as well as any value specified in a
call to new(). This allows you to programmatically tell if perl Build.PL
or any execution of ./Build had command line options specified that
override valid properties.
The runtime_params() method is essentially a glorified read-only hash. With
no arguments, runtime_params() returns the entire hash of properties
specified on the command line. With one argument, runtime_params($key)
returns the value associated with the given key.
The lifetime of the runtime_params data is for ``a build'' - that is, the
runtime_params hash is created when perl Build.PL is run (or when the
new() method is called, if the Module::Build Perl API is being used instead
of called from a shell), and lasts until perl Build.PL is run again or the
clean action is run.
script_files()Returns a hash reference whose keys are the perl script files to be
installed, if any. This corresponds to the script_files parameter to the
new() method. With an optional argument, this parameter may be set
dynamically.
For backward compatibility, the scripts() method does exactly the
same thing as script_files(). scripts() is deprecated, but it
will stay around for several versions to give people time to
transition.
This method can be used to compare a set of source files to a set of derived files. If any of the source files are newer than any of the derived files, it returns false. Additionally, if any of the derived files do not exist, it returns false. Otherwise it returns true.
The arguments may be either a scalar or an array reference of file names.
Asks the user a yes/no question using prompt() and returns true or
false accordingly. The user will be asked the question repeatedly
until they give an answer that looks like ``yes'' or ``no''.
The first argument specifies the message to display to the user (for
example, "Shall I invest your money for you?"), and the second
argument specifies the default answer (for example, "y").
Note that the default is specified as a string like "y" or "n",
and the return value is a Perl boolean value like 1 or 0. I thought
about this for a while and this seemed like the most useful way to do
it.
This method may be called as a class or object method.
In addition to the aforementioned methods, there are also some get/set accessor methods for the following properties:
PL_files()allow_mb_mismatch()allow_pureperl()auto_configure_requires()autosplit()base_dir()bindoc_dirs()blib()build_bat()build_class()build_elements()build_requires()build_script()bundle_inc()bundle_inc_preload()c_source()config_dir()configure_requires()conflicts()cover()cpan_client()create_license()create_makefile_pl()create_packlist()create_readme()debug()debugger()destdir()dynamic_config()extra_manify_args()get_options()html_css()include_dirs()install_base()installdirs()libdoc_dirs()license()magic_number()mb_version()meta_add()meta_merge()metafile()metafile2()module_name()mymetafile()mymetafile2()needs_compiler()orig_dir()perl()pm_files()pod_files()pollute()prefix()prereq_action_types()program_name()pureperl_only()quiet()recommends()recurse_into()recursive_test_files()requires()scripts()sign()tap_harness_args()test_file_exts()test_requires()use_rcfile()use_tap_harness()verbose()xs_files()
If you would like to add other useful metadata, Module::Build
supports this with the meta_add and meta_merge arguments to
new(). The authoritative list of supported metadata can be found at
the CPAN::Meta::Spec manpage but for convenience - here are a few of the more useful ones:
Ken Williams <kwilliams@cpan.org>
Copyright (c) 2001-2006 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.
perl(1), the Module::Build manpage(3), the Module::Build::Authoring manpage(3), the Module::Build::Cookbook manpage(3), the ExtUtils::MakeMaker manpage(3)
META.yml Specification: the CPAN::Meta::Spec manpage
| Module::Build::API - API Reference for Module Authors |