I need to get the output of normal Perl code to the screen and into a logfile at the same time. However a problem is that the runtime of the tool can be hours. Using Capture::Tiny's tee that means the log file will only be written to once the script terminates, which is not very useful.
To further complicate things, i need to capture the output of straight perl from the same process, as well as that of processes called with system().
Lastly, due to employer restrictions it needs to work on Win32 as well.
What other options do i have?
Use PerlIO::Util.
Just tested it under Strawberry Perl 5.12.1 32 bit and it works perfectly, so it'll be cross platform. The below code does exactly as you'd expect. And since it modifies the actual STDOUT and STDERR file handles, any writes to them will automatically be teed.
use strict;
use warnings;
use IO::Handle;
use PerlIO::Util;
use 5.012;
for (*STDOUT, *STDERR) {
$_->autoflush; $_->push_layer(tee => ">>stdout.txt");
}
for (1..10) {
say $_;
warn $_ unless $_ % 2;
}
Since none of the presented solutions were satisfactory i sat down and solved the problem on my own:
Capture::Tiny::Extended
If your program runs on a Linux/Unix platform, then you can use tee command. Tee reads stdin and writes to stdout and to a specified file.
Example:
myprogram.pl 2>&1 |tee mylog.txt
The only caveat is that stdout and stderr will be merged in the same file.
Since you are on a Windows platform, you can search Google por tee.exe, or you can try this minimalistic perl version of tee:
$|=1;
if ( !$ARGV[0] ) {
print "Usage: some_command \| tee.pl [-a] logfile\n";
exit(1);
}
# Append mode
my $mode='>';
if ($ARGV[0] eq '-a')
{
$mode='>>';
shift;
}
my $LOGFILE=$ARGV[0];
while (<STDIN>) {
print;
open( OUT, "$mode $LOGFILE");
print OUT $_;
close OUT;
# Your logic here!
}
Example:
perl myprogram.pl 2>&1 |perl tee.pl mylog.txt
I would really try to avoid modifying source code just to capture STDOUT and/or STDERR more and more if you are going to make system calls.
You can use IO::Tee.
- Create an special tee filehandle.
- Edit your program. Change all prints to stdout into prints to this filehandle.
- When required, redefine the tee filehandle to print to stdout only, or to print to 2 or more files.
- Use `` instead os system() to capture programs output and print them to the special filehandle.
If you prefer not using any module, create your own "myprint" function. It could print to stdout and, if a global flag is enabled, print to a logfile too.
sub myPrint
{
print @_;
if ($LOGMODE)
{
open(LOGFILE, ">>$logfile");
print LOGFILE @_;
close LOGFILE;
}
}
package Logger ;
# docs at the end ...
# capture conditionally the output of the command
# $objLogger->LogDebugMsg ( "Running $cmd : \n $cmd " ) ;
# $objLogger->LogDebugMsg ( `$cmd 2>&1` ) ;
use lib '.' ; use strict ; use warnings ; use Carp qw(cluck);
our ( $MyBareName , $LibDir , $RunDir ) = () ;
BEGIN {
$RunDir = '' ;
$0 =~ m/^(.*)(\\|\/)(.*)\.([a-z]*)/;
$RunDir = $1 if defined $1 ;
push ( @INC , $RunDir) ;
#debug print join ( ' ' , @INC ) ;
} #eof sub
use Timer ; use FileHandler ;
# the hash holding the vars
our $confHolder = () ;
# ===============================================================
# START OO
# the constructor
sub new {
my $self = shift;
#get the has containing all the settings
$confHolder = ${ shift @_ } ;
# Set the defaults ...
Initialize () ;
return bless({}, $self);
} #eof new
BEGIN {
# strip the remote path and keep the bare name
$0=~m/^(.*)(\\|\/)(.*)\.([a-z]*)/;
my ( $MyBareName , $RunDir ) = () ;
$MyBareName = $3;
$RunDir= $1 ;
push ( @INC,$RunDir ) ;
} #eof BEGIN
sub AUTOLOAD {
my $self = shift ;
no strict 'refs';
my $name = our $AUTOLOAD;
*$AUTOLOAD = sub {
my $msg = "BOOM! BOOM! BOOM! \n RunTime Error !!!\nUndefined Function $name(@_)\n" ;
print "$self , $msg";
};
goto &$AUTOLOAD; # Restart the new routine.
}
sub DESTROY {
my $self = shift;
#debug print "the DESTRUCTOR is called \n" ;
return ;
}
END {
close(STDOUT) || die "can't close STDOUT: $! \n\n" ;
close(STDERR) || die "can't close STDERR: $! \n\n" ;
}
# STOP OO
# =============================================================================
sub Initialize {
$confHolder = { Foo => 'Bar' , } unless ( $confHolder ) ;
# if the log dir does not exist create it
my $LogDir = '' ;
$LogDir = $confHolder->{'LogDir'} ;
# create the log file in the current directory if it is not specified
unless ( defined ( $LogDir )) {
$LogDir = $RunDir ;
}
use File::Path qw(mkpath);
if( defined ($LogDir) && !-d "$LogDir" ) {
mkpath("$LogDir") ||
cluck ( " Cannot create the \$LogDir : $LogDir $! !!! " ) ;
}
# START set default value if value not specified =========================
# Full debugging ....
$confHolder->{'LogLevel'} = 4
unless ( defined ( $confHolder->{'LogLevel'} ) ) ;
$confHolder->{'PrintErrorMsgs'} = 1
unless ( defined ( $confHolder->{'PrintErrorMsgs'} ) ) ;
$confHolder->{'PrintDebugMsgs'} = 1
unless ( defined ($confHolder->{'PrintDebugMsgs'})) ;
$confHolder->{'PrintTraceMsgs'} = 1
unless ( defined ( $confHolder->{'PrintTraceMsgs'} )) ;
$confHolder->{'PrintWarningMsgs'} = 1
unless ( defined ( $confHolder->{'PrintWarningMsgs'} ) ) ;
$confHolder->{'LogMsgs'} = 1
unless ( defined ( $confHolder->{'LogMsgs'} ) ) ;
$confHolder->{'LogTimeToTextSeparator'} = '---'
unless ( defined ( $confHolder->{'LogTimeToTextSeparator'} ) ) ;
#
# STOP set default value if value not specified =========================
} #eof sub Initialize
# =============================================================================
# START functions
# logs an warning message
sub LogErrorMsg {
my $self = shift ;
my $msg = "@_" ;
my $msgType = "ERROR" ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'LogMsgs'} == 0 ) ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'PrintErrorMsgs'} == 0 ) ;
$self->LogMsg( $msgType , "$msg" ) if ( $confHolder->{'PrintErrorMsgs'} == 1 ) ;
} #eof sub
# logs an warning message
sub LogWarningMsg {
my $self = shift ;
my $msg = "@_" ;
my $msgType = 'WARNING' ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'LogMsgs'} == 0 ) ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'PrintWarningMsgs'} == 0 ) ;
$self->LogMsg( $msgType , "$msg" ) if ( $confHolder->{'PrintWarningMsgs'} == 1 ) ;
} #eof sub
# logs an info message
sub LogInfoMsg {
my $self = shift ;
my $msg = "@_" ;
my $msgType = 'INFO' ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'LogMsgs'} == 0 ) ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'PrintInfoMsgs'} == 0 ) ;
$self->LogMsg( $msgType , "$msg" ) if ( $confHolder->{'PrintInfoMsgs'} == 1 ) ;
} #eof sub
# logs an trace message
sub LogTraceMsg {
my $self = shift ;
my $msg = "@_" ;
my $msgType = 'TRACE' ;
my ($package, $filename, $line) = caller();
# Do not print anything if the PrintDebugMsgs = 0
return if ( $confHolder->{'PrintTraceMsgs'} == 0 ) ;
$msg = "$msg : FROM Package: $package FileName: $filename Line: $line " ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'LogMsgs'} == 0 ) ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'PrintTraceMsgs'} == 0 ) ;
$self->LogMsg( $msgType , "$msg" ) if ( $confHolder->{'PrintTraceMsgs'} == 1 ) ;
} #eof sub
# logs an Debug message
sub LogDebugMsg {
my $self = shift ;
my $msg = "@_" ;
my $msgType = 'DEBUG' ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'LogMsgs'} == 0 ) ;
# Do not print anything if the PrintWarningMsgs = 0
return if ( $confHolder->{'PrintDebugMsgs'} == 0 ) ;
$self->LogMsg( $msgType , "$msg" ) if ( $confHolder->{'PrintDebugMsgs'} == 1 ) ;
} #eof sub
sub GetLogFile {
my $self = shift ;
#debug print "The log file is " . $confHolder->{ 'LogFile' } ;
my $LogFile = $confHolder->{ 'LogFile' } ;
#if the log file is not defined we create one
unless ( $confHolder->{ 'LogFile' } ) {
$LogFile = "$0.log" ;
}
return $LogFile ;
} #eof sub
sub BuildMsg {
my $self = shift ;
my $msgType = shift ;
my $objTimer= new Timer();
my $HumanReadableTime = $objTimer->GetHumanReadableTime();
my $LogTimeToTextSeparator = $confHolder->{'LogTimeToTextSeparator'} ;
my $msg = () ;
# PRINT TO STDOUT if
if ( $msgType eq 'WARNING'
|| $msgType eq 'INFO'
|| $msgType eq 'DEBUG'
|| $msgType eq 'TRACE' ) {
$msg = " $HumanReadableTime $LogTimeToTextSeparator $msgType : @_ \n" ;
}
elsif ( $msgType eq 'ERROR' ) {
$msg = " $HumanReadableTime $LogTimeToTextSeparator $msgType : @_ \n" ;
}
else {
$msg = " $HumanReadableTime $LogTimeToTextSeparator $msgType @_ \n" ;
}
return $msg ;
} #eof sub BuildMsg
sub LogMsg {
my $self = shift ;
my $msgType = shift ;
my $msg = $self->BuildMsg ( $msgType , @_ ) ;
my $LogFile = $self -> GetLogFile();
# Do not print anything if the LogLevel = 0
return if ( $confHolder->{'LogLevel'} == 0 ) ;
# PRINT TO STDOUT if
if (
$confHolder->{'PrintMsgs'} == 1
|| $confHolder->{'PrintInfoMsgs'} == 1
|| $confHolder->{'PrintDebugMsgs'} == 1
|| $confHolder->{'PrintTraceMsgs'} == 1
) {
print STDOUT $msg ;
}
elsif ( $confHolder->{'PrintErrorMsgs'} ) {
print STDERR $msg ;
}
if ( $confHolder->{'LogToFile'} == 1 ) {
my $LogFile = $self -> GetLogFile();
my $objFileHandler = new FileHandler();
$objFileHandler->AppendToFile( $LogFile , "$msg" );
} #eof if
#TODO: ADD DB LOGGING
} #eof LogMsg
# STOP functions
# =============================================================================
1;
__END__
=head1 NAME
Logger
=head1 SYNOPSIS
use Logger ;
=head1 DESCRIPTION
Provide a simple interface for dynamic logging. This is part of the bigger Morphus tool : google code morphus
Prints the following type of output :
2011.06.11-13:33:11 --- this is a simple message
2011.06.11-13:33:11 --- ERROR : This is an error message
2011.06.11-13:33:11 --- WARNING : This is a warning message
2011.06.11-13:33:11 --- INFO : This is a info message
2011.06.11-13:33:11 --- DEBUG : This is a debug message
2011.06.11-13:33:11 --- TRACE : This is a trace message : FROM Package: Morphus
FileName: E:\Perl\sfw\morphus\morphus.0.5.0.dev.ysg\sfw\perl\morphus.pl Line: 52
=head2 EXPORT
=head1 SEE ALSO
perldoc perlvars
No mailing list for this module
=head1 AUTHOR
yordan.georgiev@gmail.com
=head1 COPYRIGHT AND LICENSE
Copyright (C) 2011 Yordan Georgiev
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.1 or,
at your option, any later version of Perl 5 you may have available.
VersionHistory:
1.4.0 --- 2011.06.11 --- ysg --- Separated actions of building and printing msgs. Total refactoring. Beta .
1.3.0 --- 2011.06.09 --- ysg --- Added Initialize
1.2.0 --- 2011.06.07 --- ysg --- Added LogInfoErrorMsg print both to all possible
1.1.4 --- ysg --- added default values if conf values are not set
1.0.0 --- ysg --- Create basic methods
1.0.0 --- ysg --- Stolen shamelessly from several places of the Perl monks ...
=cut
![Prime Path[POJ3126] [SPFA/BFS]](https://oscimg.oschina.net/oscnet/e1200f32e838bf1d387d671dc8e6894c37d.jpg "Prime Path[POJ3126] [SPFA/BFS]")
