/ 
lib-root-0.10
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/ lib::root

NAME

lib::root - find perl root and push lib modules path to @INC

VERSION

version 0.10

SYNOPSIS

lib::root looks for a .libroot file on parent directories and pushes ./*/lib to @INC.

When a file does use lib::root, lib::root will try to read the file parent directories and look for a rootfile (default is .libroot) that is usually located inside a /some/dir/perl that contains many modules used by your app. Many apps have a /some/dir/perl/.perl-version file inside a perl directory, when that is the case, the app can piggy back on that filename and look for that file instead of .libroot with the example below:

use lib::root rootfile => '.perl-version';

To use the defaults, create an empty file named .libroot and place it in your /app/dir/perl/.libroot

use lib::root;

... or use another custom file to determine a libroot

use lib::root; # rootfile defaults to .libroot
use lib::root rootfile => '.perl-version';

... or add a callback if needed

use lib::root callback => sub { ... };

... or look for a given file in approot and use a perl root dir to push to inc

use lib::root rootfile => '.app-root', perldir => 'perl';

WHY IS THIS USEFUL

lib::root can be useful when your application perl modules are not installed globally.

When your app uses lib::root, the lib::root will look for the .libroot file into parent directories relative to the file using it.

For example, your app has the following structure:

/dir/myapp/perl/MyApp-Thing/lib/...
/dir/myapp/perl/MyApp-Another/lib/...
/dir/myapp/perl/MyApp-Stuff/lib/...
/dir/myapp/perl/.perl-version
/dir/myapp/bin/some_script.pl
/dir/myapp/bin/another_script.pl
/dir/myapp/.app-root

... and the app needs to push all those perl/*/lib to @INC. There are some ways to do that

Add the directory to env PERLLIB

PERLLIB=$PERLLIB:/dir/myapp/perl/MyApp-Thing/lib:/dir/myapp/perl/MyApp-Another/lib

Or use -I

perl -I/dir/myapp/perl/MyApp-Thing/lib -I/dir/myapp/perl/MyApp-Another/lib

Or use a BEGIN block:

BEGIN { push @INC, glob "/dir/myapp/perl/*/lib"; }

Or use lib::root:

use lib::root rootfile => '.perl_is_here';

lib::root can also be instructed to look in a cousin dir relative to bin in the structure above

use lib::root perldir => '../perl';

Or use lib

use FindBin qw($Bin);
use lib "$Bin/../lib";
use lib "/home/user/MyApp/lib";

Or some other way ...

USAGE

For a project with the following strucutre:

/dir/myapp/perl/MyApp-Thing/lib/MyApp/Thing.pm
/dir/myapp/perl/MyApp-Another/lib/MyApp/Another.pm
/dir/myapp/perl/MyApp-Stuff/lib/MyApp/Stuff.pm
/dir/myapp/perl/.libroot
/dir/myapp/perl/.perl-version
/dir/myapp/bin/some_script.pl
/dir/myapp/bin/another_script.pl
/dir/myapp/.app-root

EXAMPLE 1 - DEFAULT USAGE

When using /dir/myapp/perl/MyApp-Thing/lib/MyApp/Thing.pm its possible to include perl/*/lib to @INC by adding the following to Thing.pm

use lib::root;

The above will detect the location of Thing.pm and go recursively to parent directories and look for the default .libroot file. Given that the .libroot file exists under /dir/myapp/perl/.libroot (/dir/myapp/perl/) , lib::root will do: push @INC, glob "/dir/myapp/perl/*/lib";

EXAMPLE 2 - CUSTOM lib::root FILE

Some plenv projects have a .perl-version file sitting under the perl dir ie. /perl/.perl-version (see structure above). If thats the case, lib::root can piggy back on the .perl-version file with:

use lib::root rootfile => '.perl-version';

EXAMPLE 3 - CALLING FROM SCRIPT OUTSIDE perl DIRECTORY

If the project has bin directories like the structure above, and the file /dir/myapp/bin/some_script.pl needs to use lib::root, the file is outside the perl dir. It will use the .app-root file with a custom perl perldir to push libs to @INC, ie:

use lib::root rootfile => '.app-root', perldir => 'perl';

The lib::root call insite the script in bin will look for a directory that contains .app-root and then it will use the child directory perl (the perldir option) to push the modules to @INC;

The same could be done to make the .pm files above also use the .app-root instead of the .libroot. Or, also, use .libroot with a custom perldir, ie:

use lib::root perldir => 'perl';
use lib::root perldir => 'dir1/dir2/dir3/perl';
use lib::root perldir => '../perl';

EXAMPLE 4 - CALLBACKS

If necessary, lib::root also accepts a callback as an option. The callback is executed after libs are pushed to @INC ie:

use lib::root callback => sub { ... };

EXAMPLE 5 - GET ROOT DIR

IT is also possible to get the root dir calling the root sub:

my $rootdir = lib::root->root;

EXAMPLE 5 - GET ROOT DIR

IT is also possible to get the root dir calling the root sub:

my $rootdir = lib::root->root;

ACCEPTED PARAMETERS

All the parameters are optional. The default libroot file is .libroot

rootfile parameter

The rootfile parameter defines the which file lib::root must look for in parent directories.

That file (.libroot or other) must exist inside a perl $directory because lib::root will use that $dir to push to @INC.

Once lib::root finds the .libroot file inside $dir, it will push $dir/*/lib to @INC.

The default libroot file is .libroot, however you may override it with a different name, or maybe use one that already exists, for example the very used cpanfile or .perl-version

use lib::root rootfile => '.perl-version';
use lib::root rootfile => 'cpanfile';
use lib::root; #defaults to .libroot

The file must exists or lib::root will throw a warning and will not be able to push to @INC.

Example of such warning:

lib::root error: Could not find rootfile [ .libroot ]. lib::root loaded from [ /home/user/myapp/perl/MyApp/lib/MyApp.pm ].

perldir parameter

As mentioned in "rootfile parameter" section, lib::root will find the $dir that contains .libroot. Then push $dir/*/lib to @INC. However, your app might have a different structure and needs some extra directories ie. $dir/some/extra/dir/perl/*/lib to @INC.

You can add that extra dir with the perldir parameter:

use lib::root perldir => 'some/extra/dir/perl'; #push $librootdir/some/extra/dir/perl/*/lib to @INC
use lib::root rootfile => 'cpanfile', perldir => 'local/myapp'; #push $dir/local/myapp/*/lib

callback parameter

lib::root accepts a callback that will be executed after paths are pushed to @INC. However the callback will only execute if libroot found the rootfile and pushed to @INC.

use lib::root callback => sub { warn "lib::root pushed to @INC" };

rootdir function

After using lib::root it is possible to retrieve the directory that contains the rootfile.

Use the root function to get the rootdir. returns a Path::Tiny object. ie:

use lib::root;
print lib::root->rootdir; # /home/user/myapp/perl/ (Path::Tiny object)

rootdir function is an alias for the root function. If you prefer to use root:

use lib::root;
print lib::root->root; # /home/user/myapp/perl/ (Path::Tiny object)

INSTALLATION

To install this module via cpanm:

cpanm lib::root

Or via cpan shell:

cpan> install lib::root

SEE ALSO

Similar ideas have been implemented before in the modules below and possibly others

LICENSE

Copyright (C) Hernan Lopes.

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

AUTHOR

Hernan Lopes