Passing a thread queue object as a object variable in perl - multithreading

Question

I am writing a package which takes inputs like thread count,thread::Queue objects.
Once the package object is created, I will create the threads based on the input argument and dequeue the input queue in each thread and each threads executes a simple unix command like pinging to a server(changed to keep it simple).
Below is the code:
my $failed_q = Thread::Queue -> new();
my $success_q = Thread::Queue -> new();
my $process_q = Thread::Queue -> new();
package WorkerThreads;
sub new {
my $class = shift;
my $self = {
_ThreadCount => shift,
_FidQueue => shift,
_SuccessQueue => shift,
_FailedQueue => shift,
};
bless $self, $class;
return $self;
}
sub WorkerProcess
{
my ($self)=#_;
while ( my $fid = $self->{_FidQueue} -> dequeue() )
{
chomp ( $fid );
print threads -> self() -> tid(). ": pinging $fid\n";
my $result = `/bin/ping -c 1 $fid`;
if ( $? ) { $self->{_FailedQueue} -> enqueue ( $fid ) }
else { $self->{_SuccessQueue} -> enqueue ( $fid ) ; }
sleep 1;
}
print threads -> self() -> tid(). ":\n";
}
sub CreateThreads
{
my ($self)=#_;
my $Num_of_threads=$self->{_ThreadCount};
for ( 1..$Num_of_threads )
{
threads -> create ( \&WorkerProcess );
}
}
sub StartThreads
{
my ($self)=#_;
foreach my $thr ( threads -> list() )
{
$thr -> join();
}
}
sub PrintResult
{
my ($self)=#_;
while ( my $fid = $self->{_FailedQueue} -> dequeue_nb() )
{
print "$fid failed to ping\n";
}
#collate results. ('synchronise' operation)
while ( my $fid = $self->{_SuccessQueue} -> dequeue_nb() )
{
print "$fid Ping Succeeded\n";
}
}
sub ProcessRequest
{
my ($self)=#_;
$self->CreateThreads(#_);
$self->StartThreads(#_);
$self->PrintResult(#_);
}
package main;
#insert tasks into thread queue.
open ( my $input_fh, "<", "server_list" ) or die $!;
$process_q->enqueue( <$input_fh> );
close ( $input_fh );
my $Workers;
$Workers=WorkerThreads->new(
10,
$process_q,
$success_q,
$failed_q
);
$Workers->ProcessRequest();
I am getting an error while i try to dequeue in the while loop that queue is undefined. So i got this doubt like can we pass a thread queue object to a package as an argument.
Thread 1 terminated abnormally: Can't call method "dequeue" on an undefined value at .

Answer 1

You're passing a function into threads->create without any context of which object they are working within. Something like this should work
threads->create( sub { $self->WorkerProcess } );