Add option to ignore removal of IP addresses

On systems that had connectivity to e.g. IPv6 which they don't
have any more need to remove the IPv6 address from the DNS system.
Most providers do not support this and hence this case is completely
ignored and the invalid record is left in the DNS system.

diff --git a/src/ddns/providers.py b/src/ddns/providers.py
index c6ef5c0d7c0cd0a22e4f43d8ead72615e35d6e25..b66afc51bc4dae7da2fa750553bb7fffd5135a4f 100644 (file)
--- a/src/ddns/providers.py
+++ b/src/ddns/providers.py
@@ -62,6 +62,10 @@ class DDNSProvider(object):
        # the IP address has changed.
        holdoff_days = 30
 
+       # True if the provider is able to remove records, too.
+       # Required to remove AAAA records if IPv6 is absent again.
+       can_remove_records = True
+
        # Automatically register all providers.
        class __metaclass__(type):
                def __init__(provider, name, bases, dict):
@@ -158,19 +162,17 @@ class DDNSProvider(object):
                for protocol in self.protocols:
                        if self.have_address(protocol):
                                self.update_protocol(protocol)
-                       else:
+                       elif self.can_remove_records:
                                self.remove_protocol(protocol)
 
        def update_protocol(self, proto):
                raise NotImplementedError
 
        def remove_protocol(self, proto):
-               logger.warning(_("%(hostname)s current resolves to an IP address"
-                       " of the %(proto)s protocol which could not be removed by ddns") % \
-                       { "hostname" : self.hostname, "proto" : proto })
+               if not self.can_remove_records:
+                       raise RuntimeError, "can_remove_records is enabled, but remove_protocol() not implemented"
 
-               # Maybe this will raise NotImplementedError at some time
-               #raise NotImplementedError
+               raise NotImplementedError
 
        @property
        def requires_update(self):
@@ -204,12 +206,17 @@ class DDNSProvider(object):
                """
                for proto in protos:
                        addresses = self.core.system.resolve(self.hostname, proto)
-
                        current_address = self.get_address(proto)
 
-                       # If no addresses for the given protocol exist, we
-                       # are fine...
-                       if current_address is None and not addresses:
+                       # Handle if the system has not got any IP address from a protocol
+                       # (i.e. had full dual-stack connectivity which it has not any more)
+                       if current_address is None:
+                               # If addresses still exists in the DNS system and if this provider
+                               # is able to remove records, we will do that.
+                               if addresses and self.can_remove_records:
+                                       return True
+
+                               # Otherwise, we cannot go on...
                                continue
 
                        if not current_address in addresses:
@@ -285,6 +292,9 @@ class DDNSProtocolDynDNS2(object):
        # http://dyn.com/support/developers/api/perform-update/
        # http://dyn.com/support/developers/api/return-codes/
 
+       # The DynDNS protocol version 2 does not allow to remove records
+       can_remove_records = False
+
        def prepare_request_data(self, proto):
                data = {
                        "hostname" : self.hostname,
@@ -371,6 +381,7 @@ class DDNSProviderAllInkl(DDNSProvider):
        # http://all-inkl.goetze.it/v01/ddns-mit-einfachen-mitteln/
 
        url = "http://dyndns.kasserver.com"
+       can_remove_records = False
 
        def update(self):
                # There is no additional data required so we directly can
@@ -469,6 +480,7 @@ class DDNSProviderDHS(DDNSProvider):
        # grabed from source code of ez-ipudate.
 
        url = "http://members.dhs.org/nic/hosts"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -501,6 +513,7 @@ class DDNSProviderDNSpark(DDNSProvider):
        # https://dnspark.zendesk.com/entries/31229348-Dynamic-DNS-API-Documentation
 
        url = "https://control.dnspark.com/api/dynamic/update.php"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -549,6 +562,7 @@ class DDNSProviderDtDNS(DDNSProvider):
        # http://www.dtdns.com/dtsite/updatespec
 
        url = "https://www.dtdns.com/api/autodns.cfm"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -662,6 +676,7 @@ class DDNSProviderDynsNet(DDNSProvider):
        name      = "DyNS"
        website   = "http://www.dyns.net/"
        protocols = ("ipv4",)
+       can_remove_records = False
 
        # There is very detailed informatio about how to send the update request and
        # the possible response codes. (Currently we are using the v1.1 proto)
@@ -712,6 +727,7 @@ class DDNSProviderEnomCom(DDNSResponseParserXML, DDNSProvider):
        # http://www.enom.com/APICommandCatalog/
 
        url = "https://dynamic.name-services.com/interface.asp"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -753,6 +769,7 @@ class DDNSProviderEntryDNS(DDNSProvider):
        # Some very tiny details about their so called "Simple API" can be found
        # here: https://entrydns.net/help
        url = "https://entrydns.net/records/modify"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -792,6 +809,7 @@ class DDNSProviderFreeDNSAfraidOrg(DDNSProvider):
        # No information about the request or response could be found on the vendor
        # page. All used values have been collected by testing.
        url = "https://freedns.afraid.org/dynamic/update.php"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {
@@ -894,6 +912,7 @@ class DDNSProviderNamecheap(DDNSResponseParserXML, DDNSProvider):
        # https://community.namecheap.com/forums/viewtopic.php?f=6&t=6772
 
        url = "https://dynamicdns.park-your-domain.com/update"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                # Namecheap requires the hostname splitted into a host and domain part.
@@ -965,6 +984,10 @@ class DDNSProviderNsupdateINFO(DDNSProtocolDynDNS2, DDNSProvider):
        # after login on the provider user interface and here:
        # http://nsupdateinfo.readthedocs.org/en/latest/user.html
 
+       # TODO nsupdate.info can actually do this, but the functionality
+       # has not been implemented here, yet.
+       can_remove_records = False
+
        # Nsupdate.info uses the hostname as user part for the HTTP basic auth,
        # and for the password a so called secret.
        @property
@@ -1046,6 +1069,7 @@ class DDNSProviderRegfish(DDNSProvider):
        # https://www.regfish.de/domains/dyndns/dokumentation
 
        url = "https://dyndns.regfish.de/"
+       can_remove_records = False
 
        def update(self):
                data = {
@@ -1269,6 +1293,7 @@ class DDNSProviderZZZZ(DDNSProvider):
        # https://bugzilla.ipfire.org/show_bug.cgi?id=10584#c2
 
        url = "https://zzzz.io/api/v1/update"
+       can_remove_records = False
 
        def update_protocol(self, proto):
                data = {