I am very new to perl. I am working on a script that runs everyday. I want to check that current time is less than a specific time. My current solution is that I extract hour and min from localtime and then compare it. But I was told to find a better solution.

Current code:

my $flag;
for (;;) {
    $flag = GetValue();
    my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
    if( $flag ) {
        #do action here
        last;
    } elsif ( $hour <= 17 ) {
        if( $min <=30 ) {
            print STDOUT "Keep running till 17:30 \n";
            sleep 300;
        } else {
            die "Error";
        }
    } else {
        die "Error";
    }
}

Basically, the statement $flag = GetValue(); sometimes returns undefined value unexpectedly and causes the script to fail. So we want to check if $flag defined. If it is defined then we execute some code and exit the for loop. Else we check the time. If the time is less that 17:30 then we want to wait for some time and try to get the value of flag again. I only need to change the logic of comparing current time to 17:30

I want my something like:

} elsif ( $current_time <= 17:30 ) {
   print STDOUT "Keep running till 17:30 \n";
   sleep 300;
}

How do I achieve this?

CodePudding user response：

The good and solid way to deal with date-times is to use a good library, like DateTime

my $dt_mark = DateTime
    -> now(time_zone => 'local')
    -> set(hour => 17, minute => 30);

for (;;) { 
   ...

   elsif ( DateTime->now(time_zone => 'local') <= $dt_mark ) {
      ...

One can avoid constructing a new object for every comparison but that would make the code more complicated. Note that DateTime is a large library and this could be an overkill.

If the purpose is indeed to merely compare the current time to a fixed hour-minute then perhaps

elsif ( $hour < 17 or ($hour == 17 and $min <= 30) )

is good enough?

Or form and use strings that can be lexically compared

elsif ( sprintf("dd", $hour, $min) lt '1730' )