I needed to get a stack trace when a CGI program was throwing errors, so I turned to Devel::StackTrace and printed the result using CGI::Carp's set_message subroutine. That was a good start, but the result wasn't very easy to read.

So I wrote the below to colorize the output of the stack trace. The colors can be configured with the %TRACE_COLORS hash. Setting $VERBOSE to a true value will cause the arguments to the subroutines to be printed with Data::Dumper--useful if you're going to passing references. Otherwise, it'll print out the raw args.

Remember, you need to import both fatalsToBrowser and set_message from CGI::Carp for this to work.

use CGI::Carp qw( fatalsToBrowser set_message );
BEGIN {
        my %TRACE_COLORS = (
                subroutine  => 'blue',
                args        => 'red',
                file        => 'blue',
                line        => 'green',
        );
        my $VERBOSE = 1;
        sub print_stack_trace 
        {
                my $msg = shift;
                use Devel::StackTrace;
                print "<h1>Error</h1>\n";
                print "<pre>$msg</pre>\n";
                print "<hr>\n";
                print "<h3>Stacktrace</h3>\n";
                print qq(<pre>\n);

                my $trace = Devel::StackTrace->new();
                while( my $frame = $trace->next_frame() ) {
                        print qq(<font color="$TRACE_COLORS{subroutine
+}">);
                        print $frame->subroutine;
                        print qq#</font>(#;

                        if($VERBOSE) {
                                print qq(<font color="$TRACE_COLORS{ar
+gs}">);
                                use Data::Dumper 'Dumper';
                                print Dumper(+($frame->args));
                                print qq(</font>);
                        }
                        else {
                                print join ', ',
                                map {
                                        qq(<font color="$TRACE_COLORS{
+args}">').
                                        $_ .
                                        qq('</font>)
                                } $frame->args;
                        }
                        print qq#)\n\t called at #;
                        print qq(<font color="$TRACE_COLORS{file}">);
                        print $frame->filename;
                        print qq(</font> );
                        print qq(line );
                        print qq(<font color="$TRACE_COLORS{line}">);
                        print $frame->line;
                        print qq(</font>);
                        print qq(\n);
                }

                print "</pre>\n";
        }

        set_message(\&print_stack_trace);
}

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In reply to Colorized HTML stack trace by hardburn

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