add a remote_dns port property

lib/App/Netdisco/DB.pm

@@ -11,7 +11,7 @@ __PACKAGE__->load_namespaces(
 );
 
 our # try to hide from kwalitee
-  $VERSION = 74; # schema version used for upgrades, keep as integer
+  $VERSION = 75; # schema version used for upgrades, keep as integer
 
 use Path::Class;
 use File::ShareDir 'dist_dir';

lib/App/Netdisco/DB/Result/DevicePort.pm

@@ -387,6 +387,14 @@ Returns the interface index (C<ifIndex>) of the port.
 
 sub ifindex { return (shift)->get_column('ifindex') }
 
+=head2 remote_dns
+
+Returns a hostname resolved from C<remote_ip> column.
+
+=cut
+
+sub remote_dns { return (shift)->get_column('remote_dns') }
+
 =head2 remote_inventory
 
 Returns a synthesized description of the remote LLDP device if inventory

lib/App/Netdisco/DB/Result/DevicePortProperties.pm

@@ -27,6 +27,8 @@ __PACKAGE__->add_columns(
   { data_type => "text", is_nullable => 1 },
   "remote_serial",
   { data_type => "text", is_nullable => 1 },
+  "remote_dns",
+  { data_type => "text", is_nullable => 1 },
   "raw_speed",
   { data_type => "bigint", default_value => 0, is_nullable => 1 },
   "faststart",

lib/App/Netdisco/DB/ResultSet/DevicePort.pm

@@ -136,6 +136,8 @@ will add the following additional synthesized columns to the result set:
 
 =item remote_is_phone (boolean)
 
+=item remote_dns
+
 =item ifindex
 
 =back
@@ -154,11 +156,12 @@ sub with_properties {
           properties.remote_is_discoverable
           properties.remote_is_wap
           properties.remote_is_phone
+          properties.remote_dns
           properties.ifindex
         /],
         '+as' => [qw/
           error_disable_cause
-          remote_is_discoverable remote_is_wap remote_is_phone
+          remote_is_discoverable remote_is_wap remote_is_phone remote_dns
           ifindex
         /],
         join => 'properties',

lib/App/Netdisco/Worker/Plugin/Discover/PortProperties.pm

@@ -8,6 +8,7 @@ use App::Netdisco::Transport::SNMP ();
 use Dancer::Plugin::DBIC 'schema';
 
 use Encode;
+use App::Netdisco::Util::FastResolver 'hostnames_resolve_async';
 use App::Netdisco::Util::Device qw/is_discoverable match_to_setting/;
 
 register_worker({ phase => 'main', driver => 'snmp' }, sub {
@@ -25,6 +26,17 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
   my $device_ports = vars->{'device_ports'}
     || { map {($_->port => $_)} $device->ports->all };
 
+  my @remote_ips = map {{ip => $_}}
+                   grep {defined}
+                   map {$_->remote_ip}
+                   values %$device_ports;
+
+  debug sprintf ' resolving %d remote_ips with max %d outstanding requests',
+      scalar @remote_ips, $ENV{'PERL_ANYEVENT_MAX_OUTSTANDING_DNS'};
+
+  my $resolved_remote_ips = hostnames_resolve_async(\@remote_ips);
+  $properties{$_}->{remote_dns} = $_->{dns} for @$resolved_remote_ips;
+
   my $raw_speed = $snmp->i_speed_raw || {};
 
   foreach my $idx (keys %$raw_speed) {

share/schema_versions/App-Netdisco-DB-74-75-PostgreSQL.sql

@@ -0,0 +1,5 @@
+BEGIN;
+
+ALTER TABLE device_port_properties ADD COLUMN "remote_dns" text;
+
+COMMIT;