Perl: open files from array and read one by one - arrays

Question

I have an array in Perl that looks like this:
my #dynfiles = ('dyn.abc.transcript', 'dyn.def.transcript', 'dyn.ghi.transcript', 'dyn.jkl.transcript');
I'm trying to open these files and read them one by one. For this I have a code that looks like this:
foreach my $dynfile (#dynfiles) {
print "$dynfile\n";
open my $fh , '<', $dynfile or die "Could not open file\n";
my %data;
$data{$dynfile} = do {
local $/ = undef;
while (my $line = <$fh>) {
chomp $line;
if ($line =~ m/Errors:\s+0/) {
print "Dyn run status: PASS\n";
} else {
print "Dyn Run status : FAIL\n";
}
}
close $fh;
}
}
And I get this error as output:
dyn.bxt.transcript
Dyn run status: FAIL
dyn.cnl.transcript
17:25:19 : -E- Could not open dyn.cnl.transcript
So my concern is that it isn't reading the files in the array at all. Also, this file dyn.bxt.transcript had this string Errors : 0 in it, but I still get Dyn run status: FAIL in the output.
Am I doing anything wrong here? I'm using a simple pattern match, not sure where the problem is..Kindly help.
Thanks in advance!

Answer 1

After viewing reading your code and debugging in chat, I would probably go with something like this:
sub dynamo_check {
opendir(my $dh, $log_file) or die "can't opendir $log_file: $!";
my #dynfiles = grep { /^dynamo.*transcript$/ && -f "$log_file/$_" } readdir($dh);
close $dh;
foreach my $dynamofile (#dynfiles) {
print "Checking file: $dynamofile\n";
open my $fh, '<', $log_file . $dynamofile or die "$!\n";
my $passed = 0;
while(my $line = <$fh>) {
if ($line =~ m/Errors\s*:\s*0/i) {
$passed = 1;
last;
}
}
if ( $passed == 1 ) {
print "Dynamo run status: PASS\n";
$data{$dynamofile} = "pass";
}else {
print "Dynamo run status: FAIL\n";
$data{$dynamofile} = "fail";
}
}
print Dumper(\%data);
}
Summary of changes:
Add on $! to get a better error message as reference in perlvar
Use grep and readdir to find the files you want to read instead of hard coding it.
Prepend the directory path to the file name when we open the files.
Remove the do block;
Set the values in %data to pass or fail.
No need to use chomp here.
No need to set local $/ = undef;, we can go through the lines one by one and break out of the while loop with last when we find the Errors line.

Answer 2

First, let Perl tell you why it couldn't open a file:
open my $fh , '<', $dynfile or die "Could not open file $!\n";
I notice that your error message references dyn.bxt.transcript and dyn.cnl.transcript that are not in your #dynfiles. It helps is you build a complete and minimal script with sample inputs.
Then you are undefining the input record separator, after which you use a while which should only ever return the single line of the entire file. That's typically a bad thing.
Next, if looks as if your pattern doesn't match the string Errors : 0 that has a space in it.
if ($line =~ m/Errors\s*:\s+0/) {
I'm not sure what you're doing with the do. That returns the last evaluated expression, which in your case is close $fh. But, that %data hash disappears at the end of each iteration of the block. Again, strip out everything that isn't part of investigating this problem.

Answer 3

You can reduce the code using some well tested modules. For example using one of my favourite Path::Tiny, you could write:
use 5.014;
use warnings;
use Path::Tiny;
my #dynfiles = map { "dyn.$_.transcript" } qw(abc def ghi jkl);
say "Dyn run status: ",
(path($_)->slurp =~ /error\s*:\s*0\b/i)
? "PASS"
: "FAIL"
for (grep {-f} #dynfiles);