Perl::Metrics - The Perl Code Metrics System


  # Load or create the metrics database
  use Perl::Metrics '/var/cache/perl/metrics.sqlite';
  # Index and process a directory of code
  Perl::Metrics->process_directory( '/home/adam/code/mycpan' );


The Perl Code Metrics System is a module which provides a Perl document metrics processing engine, and a database in which to store the resulting metrics data.

The intent is to be able to take a large collection of Perl documents, and relatively easily parse the files and run a series of processes on the documents.

The resulting data can then be stored, and later used to generate useful information about the documents.

General Structure

Perl::Metrics consists of two primary components. Firstly, a Class::DBI/SQLite database that stores the metrics informationg.

See Perl::Metrics::File and Perl::Metrics::Metric for the two data classes stored in the database.

Secondly, a plugin structure for creating metrics packages that can interoperate with the system, allowing it to take care of document processing and data storage while the plugin can concentrate on the actual generation of the metrics.

See Perl::Metrics::Plugin for more information.

Getting Started

Perl::Metrics comes with on default plugin, Perl::Metrics::Plugin::Core, which provides a sampling of metrics.

To get started load the module, providing the database location as a param (it will create it if needed). Then call the process_directory method, providing it with an absolute path to a directory of Perl code on the local filesystem.

Perl::Metrics will quitely sit there working away, and then when it finishes you will have a nice database full of metrics data about your files.

Of course, how you actually USE that data is up to you, but you can query Perl::Metrics::File and Perl::Metrics::Metric for the data just like any other Class::DBI database once you have collected it all.


index_file $absolute_path

The index_file method takes a single absolute file path and creates an entry in the files index, referencing the file name to its hex_id for later use.

Note that this does not execute any metrics on the file, merely allows the system to "remember" the file for later.

index_directory $absolute_path

As for index_file, the index_directory method will recursively scan down a directory tree, locating all Perl files and adding them to the file index.

Returns the number of files added.


The process_index method is the primary method for generating metrics data. It triggering a metrics generation pass for all metrics on all files currently in the index.

process_directory $absolute_path

The process_directory method is a convenience method. It runs an index_directory call for the directory, and then triggers a process_index call after the index has been populated.


- Provide a more useful set of default plugins

- Provide the option to process for a subset of plugins

- Implemented automatic integration with PPI::Cache


Bugs should be reported via the CPAN bug tracker at

For other issues, contact the author.


Adam Kennedy <>


Copyright 2005 - 2008 Adam Kennedy.

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

The full text of the license can be found in the LICENSE file included with this module.