anyevent::snmp(3)使用ae::delay实现并行+顺序请求

 在实际使用中,并行的请求内部很有可能有顺序的要求.比如按设备并行,同一设备按snmp采集的oid串行.

 使用anyevent::snmp的嵌套回调,很快就会让人疯掉.

 借助coro无疑是比较好的方'案,但是在一些简单的场合,也可以使用Anyevent::Delay或者Anyevent::Delay::simple,来实现顺序请求.

 原本嵌套的回调可以写成并列的函数.同时可以传递参数.可以实现比较简单的顺序要求.

#!/usr/bin/perl
#测试anyevent::snmp 并发+串行(按设备并发,按oid串行,不能有复杂分支)
use 5.014;
use AnyEvent;
use AnyEvent::SNMP;
use Net::SNMP;
 use AnyEvent::Delay::Simple qw(delay);


my $cocurrent = 50;    # 并发数
#my @todoList = map { "192.168.6." . $_ } (1 .. 100); #
my @todoList = ("192.168.6.87","192.168.6.25","192.168.6.46"); #

my $oid=".1.3.6.1.2.1.1.1.0";  #sysDescr
my $oid1=".1.3.6.1.2.1.1.7.0";  #sysDescr


my $cv = AnyEvent->condvar;


doit() foreach 1..$cocurrent;

sub doit{
    my $ip = shift @todoList;
    return if not defined $ip;

    $cv->begin;
   # my $oid=".1.3.6.1.2.1.1.7.0";
   # my @oids=($oid);
   print "$ip.\n";
    my $sess=Net::SNMP->session (-hostname => $ip,
                     -community => "public",
                     -timeout => 1,
                     -nonblocking => 1,
                     -translate   => [-timeticks => 0x0]
                     );
    delay([    
     sub{      
     	   my $cv = shift();
     	    $cv->begin();       
		       $sess->get_request (
		           -varbindlist => [ $oid ],
		           -callback => sub {
		           	 my ($session) = @_;
		           	 my $result = $session->var_bind_list();
		
						      if (!defined $result) {
						         printf "ERROR: Get request failed for host '%s': %s.\n",
						                $session->hostname(), $session->error();
						         #die();#在回调函数里面die是没用的
						         $cv->send(-1);
						                
						      }
						      else{
						          printf "The sysDescr for host(%s) '%s' is %s.\n",$ip,
						          $session->hostname(), $result->{$oid};
						      }    
						      $cv->send( $result->{$oid});      
						          
		           }
		     );
    },
        sub{      
     	   my ($cv, @args) = @_;
     	    print ("2nd oid.(@args).\n");
     	    $cv->begin();       
		       $sess->get_request (
		           -varbindlist => [ $oid1 ],
		           -callback => sub {
		           	 my ($session) = @_;
		           	 my $result = $session->var_bind_list();
		
						      if (!defined $result) {
						         printf "ERROR: Get request failed for host '%s': %s.\n",
						                $session->hostname(), $session->error();
						         #die();
						          $cv->send(-1);
						                
						      }
						      else{
						          printf "The sysUptime for host(%s) '%s' is %s.\n",$ip,
						          $session->hostname(), $result->{$oid1};
						      }    
						      $cv->send( $result->{$oid1});      
						          
		           }
		     );
    }],
     
        sub {                          # calls on error, at this time
            print('Fail: ' . $_[1]);
            $cv->end();
             &doit(); 
        },
        sub {                          # calls on success, not at this time
        		my ($v, @args) = @_;
            print("Ok(@args).\n");
            $cv->end();
             &doit(); 
        }
     
   ); #delay
}




$cv->recv();