Change the default serial.

src/storage.cr

@@ -149,6 +149,12 @@ class DNSManager::Storage
 		# Replace domain by the real domain.
 		default_zone.replace_domain domain
 
+		# Reset the serial number so it represents the current date.
+		# This is particularly useful when a zone is deleted then re-used again right after, in this case
+		# the serial would be a problem since the new zone may not be usable for some time, depending on the
+		# configuration.
+		default_zone.reset_serial
+
 		#
 		# Actually write data on-disk.
 		#

src/storage/zone.cr

@@ -120,6 +120,16 @@ class DNSManager::Storage::Zone
 			@rrtype = "SOA"
 		end
 
+		# Sets the serial number to the current date.
+		def reset_serial
+			t = Time.local
+			y = t.year
+			m = t.month
+			d = t.day
+
+			@serial = "#{y}#{ "%0.2d" % m}#{ "%0.2d" % d}00".to_u64
+		end
+
 		def to_s(io : IO)
 			io << "(#{ "%4d" % @rrid }) "
 			io << "#{name} #{ttl} SOA (#{mname} #{rname}\n"
@@ -1009,6 +1019,16 @@ class DNSManager::Storage::Zone
 		false
 	end
 
+	# Selects the SOA entry then run the `reset_serial` procedure.
+	def reset_serial
+		@resources.each do |rr|
+			case rr
+			when SOA
+				rr.reset_serial
+			end
+		end
+	end
+
 	# When a new domain is recorded, we load a template which contains a placeholder domain.
 	# `replace_domain` replaces this domain name by the real one in the different (preloaded) RR.
 	# Do not forget the last dot ('.') to get a fully qualified domain name (FQDN).