Hi All I have been developing relatively simple perl programs on and off over the years, mainly for integrations using synchronous operations. I have since been tasked with building a "simple" ICMP and SNMP polling engine (yes re-inventing the wheel...) to allow for asynchronous/parallel polling. In researching the various options, i have learnt of the event loop options in perl. AnyEvent, IO:Async etc. Given AnyEvent has Ping and SNMP modules I have started using these and learning the ropes of AnyEvent. In testing the use cases required for the solution, I need to be able to ping different sets of hosts on different timers. So I have started developing the below code. The problem I am having is i'm getting the "AnyEvent::CondVar: recursive blocking wait attempted" error. I understand why, $cv_ping->recv; is blocking the event loop. However I am not how I work around this, or if my approach is actually going to work as I don't have much experience with AnyEvent. I have trawled the interwebs for various materials and tried different things but haven't been able to get it to work. My code is below, help/advice is much appreciated.

 use strict;

use AnyEvent;  
use AnyEvent::Ping;  
use IO::Async::Timer::Periodic;
use IO::Async::Loop;
use Data::Dumper;
my @todoList = map { "192.168.100." . $_ } (1 .. 254);

my $ping_timeout=2; #seconds to wait for response
my $ping_attemps=4; #number of pings to issue, 
my $ping_pktsize=32; #packet size of ping

my $start_run = time();

main();
sub main{
    
    my $loop = IO::Async::Loop->new;

    my $timer = IO::Async::Timer::Periodic->new(
    interval => 5,
    first_interval => 2,
    reschedule => 'hard',

    on_tick => sub {
        print "before ping\n";
        \&ping_hosts(@todoList);
        print "after ping\n";
    },
    );
    my $timer2 = IO::Async::Timer::Periodic->new(
    interval => 7,
    first_interval => 2,
    reschedule => 'hard',

    on_tick => sub {
        print "before ping2\n";
        \&ping_hosts(@todoList);
        print "after ping2\n";
    },
    );

    $timer->start;
    $timer2->start;

    $loop->add( $timer );
    $loop->add( $timer2 );

    $loop->run;
}

sub ping_hosts{
    my @hosts=@_;
    
    my $callback=shift;
    
    my $result;
    my $cv_ping = AnyEvent->condvar;
    my $ping = AnyEvent::Ping->new(packet_size => $ping_pktsize);
    $ping->timeout($ping_timeout); 
    #$cv_ping->begin(sub { shift->send($_[0]) });
    foreach my $host (@hosts) {
        $cv_ping->begin;
        my $request;
        $request = $ping->ping($host, $ping_attemps, sub {
            print "\n$host state:".Dumper($_[0]);
            undef $request;
            $cv_ping->end;
        });
        
    }
    $cv_ping->recv;
    $cv_ping->end;
    #$cv_ping->cb(sub { $_[0]->recv }); 
    $ping->end;
    
    
}
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