Unable to open text file in Perl - perl

Question

I am fetching some log files (which are in txt format) from another server and trying to parse them using my Perl script. The logs are being fetched correctly after which I set permissions to 777 for the log directory.
After this I attempt to open the log files, one by one for parsing, via my Perl script. Now, the strange thing and the problem which happens is, my script is sometimes able to open the file and sometimes NOT. To put it simply, it's unable to open the log files for parsing at times.
Also, I have cronned this perl script and the chances of file open failing are greater when it runs via cron rather than manually, although they have run successfully in both cases previously. I don't understand where the issue lies.
Here is the code which I use for opening the files,
$inputDir = "/path/to/dir";
#inputFiles = <$inputDir/*>;
# inputFiles array is list of files in the log directory
foreach my $logFile(#inputFiles)
{
# just to ensure file name is text
$logFile = $logFile."";
# process file only if filename contains "NOK"
if(index($logFile,"NOK") > -1)
{
# opens the file
open($ifile, '<', $logFile) or die "Error: Unable to open file for processing.";
# file parsing takes place
}
}
close($ifile);
I want to re-iterate that this code HAS run successfully and I haven't changed any part of it. Yet, it does not run every time without fail, because its unable to open the log file at times. Any ideas?

Answer 1

You should include the error message $! and the file name $logFile in your die string to see why the open failed, and for which file.
open($ifile, '<', $logFile) or die "Error: Unable to open $logFile: $!";
Also, this line:
$logFile = $logFile."";
...is quite redundant. If a conversion is necessary, perl will handle it.

Answer 2

Just as an example, this is what you code should look like. You may like to try this version
use strict;
use warnings;
my $inputDir = '/path/to/dir';
my #inputFiles = <$inputDir/*>;
foreach my $logFile (grep /NOK/, #inputFiles) {
open my $ifile, '<', $logFile or die qq(Unable to open "$logFile": $!);
# Process data from <$ifile>;
}

Answer 3

Maybe opening some files fails, because your program has too many open files. Your program opens all files in $inputDir and processes them in the loop. After that it closes the last file opened.
EDIT: after reading TLP's comment and reading perldoc -f close and perldoc -f open I see that TLP is right and the filehandle in $ifile is closed by a subsequent open($ifile,'<',$logFile) . However, if the file parsing code not shown by the topic creator creates another reference to $ifile the file handle would stay open.
Moving the call to close into the if block should solve your problem:
$inputDir = "/path/to/dir";
#inputFiles = <$inputDir/*>;
# inputFiles array is list of files in the log directory
foreach my $logFile(#inputFiles)
{
# process file only if filename contains "NOK"
if(index($logFile,"NOK") > -1)
{
# opens the file
# added my to $ifile to keep local to this scope
open(my $ifile, '<', $logFile) or die "Error: Unable to open file for processing.";
# file parsing takes place
# close current file
close($ifile);
}
}