Can I use a AnyEvent->timer() in a AnyEvent::Fork ?

Question

Let's say I work with a number N of account object.

I would like to create for N Account, several forks, and independently include an event AnyEvent-> timer (). here is what my code looks like:

for my $num_account (1..2) {

my $fork_1 = AnyEvent::Fork
->new
->require ("TweetFactory")
->fork
->run ("TweetFactory::worker",sub {
    my ($master_filehandle) =@_;

    my $wait1 = AnyEvent->timer(after => 0, interval => 100 ,cb => sub {

    my $account = UsersPool::get_account($num_account);

    my $tf = new TweetFactory ({account => $account, topic => $topic});

    %search_article = $tf->search_articles_from_topic_list($dbh,\$db_access,@rh_website);
    $tf->save_url_to_process($dbh,\$db_access,%search_article);
    @url_to_process = $tf->get_url_to_process(100,$dbh,\$db_access);
    %articles_urls_titles = $tf->get_infos_url($mech,@url_to_process);
    $tf->save_url_processed($dbh,\$db_access,%articles_urls_titles);

                });
       });

my $fork_2 = AnyEvent::Fork
->new
->require ("TargetUsers")
->fork
->run ("TargetUsers::worker",sub {
    my ($master_filehandle) =@_;
    my $wait2 = AnyEvent->timer(after => 0, interval => 80, cb => sub {     
    my $account = UsersPool::get_account($num_account);

    TargetUsers::save_all_messages($account,$dbh,\$db_access);  

                });
       });   

my $fork_3 = AnyEvent::Fork
->new
->require ("TargetUsers")
->fork
->run ("TargetUsers::worker",sub {
    my ($master_filehandle) =@_;

    my $wait3 = AnyEvent->timer(after => 0 , interval => 80, cb => sub {        
    my $account = UsersPool::get_account($num_account);

    TargetUsers::save_followers($dbh,\$db_access,$account);
                });
       });

AnyEvent::Loop::run;
}

But during the execution, the timers does not start.

I have, on the contrary, tried to launch an event AnyEvent-> timer in which I create my fork :

my $wait2 = AnyEvent->timer(after => 0, interval => 10, cb => sub {         
my $fork_2 = AnyEvent::Fork
    ->new
    ->require ("TargetUsers")
    ->fork
    ->run ("TargetUsers::worker",sub {
    my ($master_filehandle) =@_;

    my $account = UsersPool::get_account($num_account);

    TargetUsers::save_all_messages($account,$dbh,\$db_access);  

       });
            });   

At this moment, the event was well launched, but I had to wait for the execution of the last event to create the next fork.

Have you some idea please ? Thanks

Answer 1

First some observations: in your example, you do not need to call ->fork. You also don't show the code running in the forked process, you only show how you create timers in the parent process, and these should certainly work. Lastly, you don't seem to do anything with the forked process (you do nothing to the $master_filehandle).

More importantly, your example creates and instantly destroys the fork objects, they never survive the loop, and you actually call the loop function inside your for loop, so probably you don't loop more than once

Maybe there is some misunderstanding involved - the callback you pass to run is executed in the parent, the same process whjere you execute AnyEvent::Fork->new, The code that runs in the child would be the TargetUsers::worker function for example.

To make timers work in the newly created processes, you would need to run an event loop in them.

Maybe AnyEvent::Fork::RPC with the async backend would be more suited for your case: it runs an event loop for you, it has a simpler request/response usage and it can pass data to and from the newly created process.