NAME

    Devel::Trace::Subs - Generate, track, store and print code flow and
    stack traces.

SYNOPSIS

        use Devel::Trace::Subs qw(trace trace_dump install_trace remove_trace);

    Add a trace() call to the top of all your subs

        trace(); # or even better: $trace() if $ENV{DTS_ENABLE};

    Enable the module anywhere in the stack (preferably the calling script)

        $ENV{DTS_ENABLE} = 1;

    From anywhere (typically near the end of the calling script) dump the
    output

        trace_dump();

    Automate the installation into a file (or all files in a directory)

        install_trace(file => 'filename'); # or directory, or 'Module::Name'

    Remove the effects of install_trace()

        remove_trace(file => 'filename')

    See EXAMPLES for further details.

DESCRIPTION

    This module facilitates keeping track of a project's code flow and
    stack trace information in calls between subroutines.

    Optionally, you can use this module to automatically inject the
    appropriate trace() calls into all subs in individual files, all Perl
    files within a directory structure, or even in production files by
    specifying its Module::Name.

    It also has the facility to undo what was done by the automatic
    installation mentioned above.

EXPORT

    None by default. See EXPORT_OK.

EXPORT_OK

    trace, trace_dump, install_trace, remove_trace

FUNCTIONS

 trace

    Parameters: None

    In order to enable tracing, you must set $ENV{DTS_ENABLE} to a true
    value somewhere in the call stack (preferably in the calling script).
    Simply set to a false value (or remove it) to disable this module.

    Puts the call onto the stack trace. Call it in scalar context to
    retrieve the data structure as it currently sits.

    Note: It is best to write the call to this function within an if
    statement, eg: trace() if $ENV{DTS_ENABLE};. That way, if you decide to
    disable tracing, you'll short circuit the process of having the
    module's trace() function being loaded and doing this for you.

    If you set $ENV{DTS_FLUSH_FLOW} to a true value, we'll print to STDOUT
    a single line of code flow during each trace() call. This helps in
    figuring out where a program is having trouble, but the program itself
    isn't outputting anything useful.

 trace_dump

    Dumps the output of the collected data.

    All of the following parameters are optional.

    want => 'string', type => 'html', file => 'file.ext'

    want: Takes either 'flow' or 'stack', and will output the respective
    data collection. If this parameter is omitted, both code flow and stack
    trace information is dumped.

    type: Has only a single value, 'html'. This will dump the output in
    HTML format.

    file: Takes the name of a file as a parameter. The dump will write
    output to the file specified. The program will die if the file can not
    be opened for writing.

 install_trace

    Automatically injects the necessary code into Perl files to facilitate
    stack tracing.

    Parameters:

    file => 'filename' - Mandatory: 'filename' can be the name of a single
    file, a directory, or even a 'Module::Name'. If the filename is a
    directory, we'll iterate recursively through the directory, and make
    the changes to all .pl and .pm files underneath of it (by default). If
    filename is a 'Module::Name', we'll load the file for that module
    dynamically, and modify it. CAUTION: this will edit live production
    files.

    extensions => ['*.pl', '*.pm'] - Optional: By default, we change all
    *.pm and *.pl files. Specify only the extensions you want by adding
    them into this array reference. Anything that File::Find::Rule::name()
    accepts can be passed in here.

    inject => ['your code here;', 'more code;'] - The lines of code
    supplied here will override the default. Note that remove_trace() will
    not remove these lines, and for uninstall, you'll have to manually
    delete them.

 remove_trace

    Automatically remove all remnants of this module from a file or files,
    that were added by this module's install_trace() function.

    Parameters: file => 'filename'

    Where 'filename' can be the name of a file, a directory or a
    'Module::Name'.

EXAMPLES

    One-liner to install into a live module:

        sudo perl -MDevel::Trace::Subs=install_trace -e 'install_trace(file => "Data::Dump");'

    One-liner to test that it worked:

        perl -MData::Dump -MDevel::Trace::Subs=trace_dump -e '$ENV{DTS_TRACE}=1; dd {a=>1}; trace_dump();'

    One-liner to uninstall:

        sudo perl -MDevel::Trace::Subs=remove_trace -e 'remove_trace(file => "Data::Dump");'

    Install into all *.pm files in a directory structure:

        use warnings;
        use strict;
    
        use Devel::Trace::Subs qw(install_trace);
    
        install_trace(
                    file => '/path/to/files/',
                    extensions => ['*.pm'],
                 );

AUTHOR

    Steve Bertrand, <steveb at cpan.org>

BUGS

    Please report any bugs or feature requests to bug-devel-trace-flow at
    rt.cpan.org, or through the web interface at
    http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Devel-Trace-Subs. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

REPOSITORY

    https://github.com/stevieb9/devel-trace-subs

BUILD REPORTS

    CPAN Testers: http://matrix.cpantesters.org/?dist=Devel-Trace-Subs

SUPPORT

    You can find documentation for this module with the perldoc command.

        perldoc Devel::Trace::Subs

    You can also look for information at:

      * RT: CPAN's request tracker (report bugs here)

      http://rt.cpan.org/NoAuth/Bugs.html?Dist=Devel-Trace-Subs

      * Search CPAN

      http://search.cpan.org/dist/Devel-Trace-Subs/

LICENSE AND COPYRIGHT

    Copyright 2016 Steve Bertrand.

    This program is free software; you can redistribute it and/or modify it
    under the terms of either: the GNU General Public License as published
    by the Free Software Foundation; or the Artistic License.

    See http://dev.perl.org/licenses/ for more information.

