in reply to Firebird databases backup script

@Anonymous Monk
Once again thanks for your help. Glob solves line break issue but... brings another one problem. 

#Create database filenames table @files
my @ext = ("fb", "gdb", "ib");
my $data = "/opt/databases";

foreach (@ext) {
        my $load = glob "$data*.$_";
        push (@files, $load);
}

foreach (@files) {
print "Found database: $_ \n";
}

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/opt/databases contains 5 files. Two with fb extension, three with gdb. Foreach loop should (as i think) push to @files table all filenames with extensions from @ext. Now this code works only for first extension on table @ext and second issue it inserts me in table @files first and last item empty. The execution result looks: 
Found database:
Found database: /opt/databases/DEMO.fb
Found database: /opt/databases/demo2.fb
Found database:

[download]
The first and last are unwanted, they breaks the script at gbak - it dies due to empty filename to backup.
Second thing - why foreach loop breaks after first item from list and don`t push to @files other files as i think it should?

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Re^2: Firebird databases backup script
by Anonymous Monk on Mar 02, 2012 at 01:00 UTC
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      Thank you. Now I see where I`m wrong. More than one result is output of glob but I insert them to variable but should be inserted to table.
      I`ve fixed it to @files 
      foreach (@ext) {
        my @load = glob "$data*.$_";
        push (@files, @load);
}

      [download]
      but still first element of @files table is empty.
      The output: 
       
2012-03-02-09-46-09: Found database:
 2012-03-02-09-46-09: Found database: /opt/databases/DEMO.fb
 2012-03-02-09-46-09: Found database: /opt/databases/demo2.fb
 2012-03-02-09-46-09: Found database: /opt/databases/demo.gdb
 2012-03-02-09-46-09: Found database: /opt/databases/demo2.gdb
 2012-03-02-09-46-09: Found database: /opt/databases/demo3.gdb
 2012-03-02-09-46-09: Found database: /opt/databases/simplemarketing.g
+db
 2012-03-02-09-46-09: Found database: /opt/databases/SimpleMarketing2.
+gdb

      [download]
      The script dies at first element because gbak can`t perform backup on empty file as source.
      For now to cut out the first empty element from @files i`ve just used  shift(@files); but I`m not sure is this a good idea. I don`t know why it push first element empty to @files and if in some conditions e.g. on other server the first element will not be empty the shift will be cutting out one of databases from backup.
      Is there a better way to check array for empty elements and if exist shift them? I have two ideas - insert if in foreach loop or do another one foreach loop for @files to remove the empty elements. In both ideas I don`t know how to correctly detect empty elements.
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        Hello!

        For now to cut out the first empty element from @files i`ve just used shift(@files);

        No, it's not a good idea, better make sure the path is valid before adding it, or at least before calling gbak.

        Using a file search and backup what it finds is also not a good idea for production code, maybe only as an learning exercise, for the reason you gave yourself, it may skip some databases without even noticing. Better to make a config with all databases to backup, check everything that you think (or even what you don't thing :) ) that it can go wrong and log the errors. 

        use strict;
use warnings;

my @files;
my @ext = (qw{fb gdb ib fdb});

my $data = "/opt/databases/";                     # notice the final /

foreach my $ext (@ext) {
    my @load = glob "$data*.$ext";
    push (@files, @load);
}

foreach my $db (@files) {
    if (-f $db) {
        print "Found database: $db \n";
    }
    else {
        print "skiping '$db'...\n";
    }
}

# Alternatively:

foreach my $ext (@ext) {
    my @load = glob "$data*.$ext";
    foreach my $file (@load) {
        if (-f $file) {
            push (@files, $file);
        }
        else {
            print "Something is wrong, with '$file'!\n";
        }
    }
}

foreach my $db (@files) {
    print "Found database: $db \n";
}

        [download]

        Here is a piece from my backup script based on "IPC::Run3 - run a subprocess with input/ouput redirection", learned from Re^3: Using SYSTEM2 on Windows, thanks to ikegami :)

        use strict;
use warnings;
use IPC::Run3 qw( run3 );

my $FBUSER = 'SYSDBA';
my $FBPASS = 'masterkey'; # this is secret ;)
my $gbak = 'gbak';
my $host = 'localhost';
my $db = '/opt/databases/test.fdb';
my $bk = '/opt/databases/backup/test.fbk';

# Backup the database on remote (or local) server
my $cmd = qq{$gbak -backup -service "$host:service_mgr" "$db" "$bk" -u
+ser "$FBUSER" -pass "$FBPASS"};

run3 $cmd, undef, \my @out, \my @err;

print "STDOUT: $_" for @out;
if (scalar @err > 0) {
    print "\n--- Errors ----------------------------------------------
+---\n";
    print " $_" for @err;
    print "-----------------------------------------------------------
+-\n\n";
}
else {
    print " Backup completed successfully.\n";
}

        [download]

        Regards, Ştefan

        Update: refactored code that was silently skipping elements from the list.

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