Manual Reference Pages  - Apache::TestTrace (3)


Apache::TestTrace - Helper output generation functions



    use Apache::TestTrace;

    debug "foo bar";

    info_sub "missed it";

    error_mark "something is wrong";

    # test sub that exercises all the tracing functions
    sub test {
        print $Apache::TestTrace::LogFH
              "TraceLevel: $Apache::TestTrace::Level\n";
        $_->($_,[1..3],$_) for qw(emerg alert crit error
                                  warning notice info debug todo);
        print $Apache::TestTrace::LogFH "\n\n"

    # demo the trace subs using default setting

        # override the default trace level with ’crit’
        local $Apache::TestTrace::Level = ’crit’;
        # now only ’crit’ and higher levels will do tracing lower level

        # set the trace level to ’debug’
        local $Apache::TestTrace::Level = ’debug’;
        # now only ’debug’ and higher levels will do tracing lower level

        open OUT, ">/tmp/foo" or die $!;
        # override the default Log filehandle
        local $Apache::TestTrace::LogFH = \*OUT;
        # now the traces will go into a new filehandle
        close OUT;

    # override tracing level via -trace opt
    % t/TEST -trace=debug

    # override tracing level via env var


This module exports a number of functions that make it easier generating various diagnostics messages in your programs in a consistent way and saves some keystrokes as it handles the new lines and sends the messages to STDERR for you.

This module provides the same trace methods as syslog(3)’s log levels. Listed from low level to high level: emerg(), alert(), crit(), error(), warning(), notice(), info(), debug(). The only different function is warning(), since warn is already taken by Perl.

The module provides another trace function called todo() which is useful for todo items. It has the same level as debug (the highest).

There are two more variants of each of these functions. If the _mark suffix is appended (e.g., error_mark) the trace will start with the filename and the line number the function was called from. If the _sub suffix is appended (e.g., error_info) the trace will start with the name of the subroutine the function was called from.

If you have Term::ANSIColor installed the diagnostic messages will be colorized, otherwise a special for each function prefix will be used.

If Data::Dumper is installed and you pass a reference to a variable to any of these functions, the variable will be dumped with Data::Dumper::Dumper().

Functions whose level is above the level set in $Apache::TestTrace::Level become NOPs. For example if the level is set to alert, only alert() and emerg() functions will generate the output. The default setting of this variable is warning. Other valid values are: emerg, alert, crit, error, warning, notice, info, debug.

Another way to affect the trace level is to set $ENV{APACHE_TEST_TRACE_LEVEL}, which takes effect if $Apache::TestTrace::Level is not set. So an explicit setting of $Apache::TestTrace::Level always takes precedence.

By default all the output generated by these functions goes to STDERR. You can override the default filehandler by overriding $Apache::TestTrace::LogFH with a new filehandler.

When you override this package’s global variables, think about localizing your local settings, so it won’t affect other modules using this module in the same run.


 o provide an option to disable the coloring altogether via some flag
   or import()


Stas Bekman with contributions from Doug MacEachern

perl v5.8.8 Apache::TestTrace (3) 2007-12-31
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