NAME

Devel::Events - Extensible instrumentation framework

VERSION

version 0.10

SYNOPSIS

        use Devel::Events::Generator::Foo;
        use Devel::Events::Handler::Bar;
        use Devel::Events::Filter::Blort;
        my $h = Devel::Events::Generator->new(
                handler => Devel::Event::Filter->new(
                        handler => Devel::Events::Handler::Bar->new(),
                ),
        );

DESCRIPTION

Devel::Events is an event generation, filtering and analaysis framework for instrumenting and auditing perl code.

The design's purpose is to decouple the mechanics of code instrumentation from the analysis, making it easier to write debugging/profiling tools.

Devel::Events::Generator object fire events, which can be mangled by Devel::Event::Filter objects. Eventually any number of Devel::Event::Handler objects can receive a given event, and perform analysis based on it.

For example Devel::Event::Handler::ObjectTracker can be used to detect leaks.

COMPONENT OVERVIEW

There are two main types of components - generators and handlers.

Filters are special types of handlers that always delegate to another handler.

The multiplex handler may be used to delegate to any number of handlers, and can be the handler for several generators.

Using these basic components complex chains of handlers can be built to properly analyze the events you are interested in.

Generators

Devel::Events::Generator::Objects: Generate "object_bless" and "object_destroy" events by overriding "CORE::GLOBAL::bless" and tracking every object using Variable::Magic.
Devel::Events::Generator::SubTrace: Uses the perl debugger hook to generate "enter_sub" and "leave_sub" events.
Devel::Events::Generator::LineTrace: Fires an "executing_line" event for every line using the perl debugger hook.
Devel::Events::Generator::Require: Fires events for "require" and c<use> calls.

Handlers

Devel::Events::Handler::Multiplex: Repeat events to multiple handlers.
Devel::Events::Handler::Callback: Make a handler object out of a callback.
Devel::Events::Handler::Log::Memory: Log all events to an array.
Provides filtering and slicing methods to ease analysis.
Devel::Events::Handler::ObjectTracker: Handles "object_bless" and "object_destroy" events (as generated by Devel::Events::Generator::Objects) to track the lifetime of objects. When objects lifetimes extend beyond the scope they're supposed to be destroyed in leaks can be detected.}

Filters

Devel::Events::Filter::Stamp: Add various stamp data (time, process ID, thread ID if threads are loaded) to events.
Devel::Events::Filter::Stringify: Stringify (by default using "StrVal" in overload, to avoid side effects) all event data to avoid leaking.
Devel::Events::Filter::Size: Add size reports to events using Devel::Size
Devel::Events::Filter::RemoveFields: Remove certain fields from events.
Devel::Events::Filter::Warn: Runs "warn "@event"" before delegating to the sub handler. Useful for debugging handler chains.

EVENT STRUCTURE

All events are passed as lists.

The default components will generate lists containing a single string which is the event name, and then a list of key/value pairs.

SUPPORT

Bugs may be submitted through the RT bug tracker <https://rt.cpan.org/Public/Dist/Display.html?Name=Devel-Events> (or bug-Devel-Events@rt.cpan.org <mailto:bug-Devel-Events@rt.cpan.org>).

AUTHOR

יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

CONTRIBUTOR

Karen Etheridge <ether@cpan.org>

COPYRIGHT AND LICENCE

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.