[#159] Macsuck archive behaviour same as ND1 (unseen nodes remain active)

Netdisco/lib/App/Netdisco/Core/Macsuck.pm

@@ -112,10 +112,15 @@ sub do_macsuck {
     $ip, $total_nodes;
 
   # a use for $now ... need to archive dissapeared nodes
-  my $archived = schema('netdisco')->resultset('Node')->search({
-    switch => $ip,
-    time_last => { '<' => \$now },
-  })->update({ active => \'false' });
+  my $archived = 0;
+
+  if (setting('node_freshness')) {
+      $archived = schema('netdisco')->resultset('Node')->search({
+        switch => $ip,
+        time_last => \[ "< ($now - ?::interval)",
+          setting('node_freshness') .' minutes' ],
+      })->update({ active => \'false' });
+  }
 
   debug sprintf ' [%s] macsuck - removed %d fwd table entries to archive',
     $ip, $archived;

Netdisco/lib/App/Netdisco/Manual/Configuration.pod

@@ -741,6 +741,21 @@ Value: Number. Default: 1.
 Seconds nbtstat will wait for a response before time out.  Accepts fractional
 seconds as well as integers.
 
+=head3 C<node_freshness>
+
+Value: Number of Minutes. Default: 0
+
+Controls the behaviour of Netdisco when a node (workstation, printer, etc) has
+disappeared from the network (device MAC address tables).
+
+If set to 0, the default, nodes will remain on the last-seen switch port until
+"C<expire_nodes>" days have passed (when they'll be deleted if you run the
+Expire job). This is the same behaviour as Netdisco 1.
+
+Set to a number of minutes to enforce some kind of ageing on this data. For
+example you could set to 60 to match the default macsuck schedule, meaning
+nodes are archived if they're not in the device tables at the time of polling.
+
 =head3 C<expire_devices>
 
 Value: Number of Days. Default: 60