如何通过命令行开关为我的Perl程序启用调试模式？

有许多模块可以处理日志记录. Log4Perl是一个非常流行的记录模块.

如果你真的,真的想通过避免CPAN来限制自己(这是一个坏主意),你可以很容易地将一个记录模块放在一起.

这是我为你砍的一小部分.它需要测试和真实的文档等等.我还使用了一些高级技术,比如自定义import()方法.围绕我使用单个变量来存储整个应用程序的DEBUG设置也存在一些问题.但它的确有效.我在一个项目中使用了类似的模块,并对它非常满意.

package QLOG;

use strict;
use warnings;
use Carp qw(croak);

our %DEBUG_OPTIONS;
our %VALID_DEBUG_OPTIONS;
our %DEBUG_CONFLICTS;

sub import {

    my $pkg = shift;
    my $target = caller();

    my %opts = @_;


    # Configure options

    croak "Must supply an array ref of valid modes"
       unless exists $opts{options};

    @VALID_DEBUG_OPTIONS{ @{$opts{options}} } = ();

    # Configure conflicts

    if( exists $opts{conflicts} ) {
        @DEBUG_CONFLICTS{ keys %{$opts{conflicts}} } 
            = values %{$opts{conflicts}}
    }

    # Export DEBUG method

    {   no strict 'refs';
        *{$target.'::DEBUG'} = &;DEBUG;
    }

    return;
}

sub DEBUG {
    my $mode = shift;

    croak "DEBUG mode undefined"
        unless defined $mode;

    return unless
        ( $mode eq 'ANY' and %DEBUG_OPTIONS )
        or exists $DEBUG_OPTIONS{$mode};

    warn "$_n" for @_;

    return 1;
}


sub set_options {

    for my $opt ( @_ ) {
        die "Illegal option '$opt'"
           unless exists $VALID_DEBUG_OPTIONS{$opt};

        $DEBUG_OPTIONS{$opt}++;
    }

    return;
}

sub check_option_conflicts {

    for my $opt ( keys %DEBUG_OPTIONS ) {

        if (exists $DEBUG_CONFLICTS{$opt}) {

            for ( @{$DEBUG_CONFLICTS{$opt}} ) {

                die "Debug option $opt conflicts with $_" 
                    if exists $DEBUG_OPTIONS{$_} 
            }
        }
    }

    return;
}


1;

然后像这样使用它：

#!/usr/bin/perl 

use strict;
use warnings;


use Getopt::Long;

use QLOG
    options => [qw(
        VERBOSE
        SUPPRESS_ERROR_MSGS
        IGNORE_VALIDATION
        SETPPING_COMPUTATION
    )],conflicts => {
        VERBOSE => [qw(
            SUPPRESS_ERROR_MSGS
            SETPPING_COMPUTATION
        )],};




process_args();

DEBUG VERBOSE => 'Command line data parsed.';

main();

### ---------------

sub main {

    DEBUG VERBOSE => 'BEGIN main()';

    if( DEBUG 'ANY' ) {
        print "debug_mode is ONn";
    }
    else {
        print "debug_mode is OFFn";
    }

    warn "Error which could be surpressedn"
        unless DEBUG 'SUPPRESS_ERROR_MSGS';
}


# Get arguments and process flags like 'v' and 'sc' into strings specified
# in QLOG configuration above.
# This processing makes the nice DEBUG VERBOSE => 'blah'; syntax work.
sub process_args {

    # Use Getopt::Long to parse @ARGV

    my @debug_options;
    GetOptions (
        'debug-options=s@' => @debug_options,'help'             => &;usage,) or usage();

    # Convert option flags to strings.
    my %option_lut = qw(
        v  VERBOSE  
        s  SUPPRESS_ERROR_MSGS
        i  IGNORE_VALIDATION 
        c  SETPPING_COMPUTATION 
    );

    my @options = map {          # This chained map 
        exists $option_lut{$_}   #    looks in the lut for a flag
        ? $option_lut{$_}        #       translates it if found
        : $_                     #       or passes on the original if not.
    } 
    map {                        # Here we split 'cv' into ('c','v')
       split //
    } @debug_options;

    # Really should use Try::Tiny here.
    eval {    
        # Send a list of strings to QLOG
        # QLOG will make sure they are allowed.
        QLOG::set_options( @options );

        QLOG::check_option_conflicts(); 

        1;          # Ensure true value returned if no exception occurs.
    } or usage($@);

    return;
}

sub usage {

    my $message = shift || '';
    $message = '' if $message eq 'help';

    print <<"END";
$message

Use this proggy right.

END

    exit;
}

您可能希望添加一个方法以使您的调试消息可以抑制.

就像是：

sub SUPPRESSED_BY {
     my $mode = shift;

     return if exists $DEBUG_OPTIONS{$mode);

     return @_; 
}

导出符号然后使用它：

DEBUG VERBOSE => SUPPRESSED_BY SUPPRESS_ERRORS => 'My message here';

将日志记录模块放在一起的容易性导致存在大量可用的这种模块.有很多方法可以完成这项任务,并且在检测代码时需要有不同的变化,甚至更多.我甚至编写了一些记录模块来满足各种需求.

无论如何,当你首先潜入Perl时,这应该会给你一个严重的扣篮.

随意问我’到底是什么？’输入问题.我意识到我在向你扔了很多东西.