commit code

ovh-dns-updater.py

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+#!/usr/bin/env python
+# -*- encoding: utf-8 -*-
+
+
+import json
+import ovh
+import sys
+import requests, time
+
+'''
+API credentials
+can be provided in variety of ways:
+(see https://github.com/ovh/python-ovh#configuration)
+-explicitly here :
+'''
+#client = ovh.Client(
+#        endpoint           = "ovh-eu",
+#        application_key    = "XXXXXXXXXXXXXXXX",
+#        application_secret = "YYYYYYYYYYYYYYYY",
+#        consumer_key       = "ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ"
+#        )
+'''
+-or in the ENVIRONMENT 
+-or in a ovh.conf file
+in which cases we can call with no argument (the ovh module gets the credentials on its own):        
+'''
+client = ovh.Client() 
+
+default_ttl =  600  # seconds 
+# ttl = how long will a DNS server cache the value before checking it at the Registrar. Longer value yields faster name resolution most of the time, but less frequent updates
+
+# list of hosts (=subdomain.domain.tld) to update, each a dictionnary with at least "domain" and "subdomain" defined
+hosts = [
+        { 
+            "domain": "mydomain.tld", # Required
+            "subdomain": "www", # Required. Explicit subdomain or empty string "" (for @) or "*" for wildcard
+            #"ipv6": any_value_except_False # Optional : maintain corresponding record, when possible
+            "ipv4": False, #explicitly disable modifiying ipv4 (A) records, even if public IPV4 exists (a possibly erroneous record would be left as-is)
+            #"ttl": 60 # optional : if 'ttl' in specified in host, overrides the global default value 
+        },
+        { 
+            "domain": "otherdomain.tld",
+            "subdomain": ""
+            # 'ipv4' and 'ipv6' are not listed : automatically maintain any/both records, according to availability
+        }
+    ]
+
+checkDNS_interval_hrs = 12.1 # when the saved IP addresses are old, check the DNS record, even if the addresses did not change
+#save last known address in local file. 
+current_ip_file = "/tmp/current_ip.json" 
+
+
+def get_current_ip(v = 4):
+    url = 'https://api6.ipify.org' if v == 6 else 'https://api.ipify.org'
+    try :         
+        r = requests.get(url, timeout=5.0)
+    except requests.exceptions.RequestException as e:
+        print("failed getting ipv{} address because {} occurred".format(v, str(e)))
+        return False
+    return r.text if r.status_code == requests.codes.ok else False
+
+def update_record(domain, subdomain, new_ip, _ttl = 600):
+    """
+    Update the (A or AAAA) record with the provided IP
+    """
+
+    typ = 'AAAA' if ":" in new_ip else 'A'
+    print("checking record {} for {}.{}".format(typ,subdomain,domain))
+    path = "/domain/zone/{}/record".format(domain)
+    result = client.get(path,
+                        fieldType = typ,
+                        subDomain = subdomain
+                     )
+
+    if len(result) != 1:
+        print("### creating NEW record {} for {}.{}".format(typ,subdomain,domain))
+        result = client.post(path,
+                    fieldType = typ,
+                    subDomain = subdomain,
+                    target = new_ip,
+                    ttl = _ttl
+                     )
+        client.post('/domain/zone/{}/refresh'.format(domain))
+        result = client.get(path,
+                        fieldType=typ,
+                        subDomain=subdomain
+                        )
+        record_id = result[0]
+    else :
+        # record exists
+        record_id = result[0]
+        path = "/domain/zone/{}/record/{}".format(domain,record_id)
+        result = client.get(path)
+        oldip = result['target']
+        print('record exists, with ip :',oldip)
+        if oldip == new_ip :
+            print('nothing to do')
+            return
+        else :
+            print('updating to ', new_ip)
+            result = client.put(path, 
+                subDomain = subdomain, 
+                target = new_ip, 
+                ttl = _ttl
+                 )
+            client.post('/domain/zone/{}/refresh'.format(domain))
+    #checking changes
+    result = client.get("/domain/zone/{}/record/{}".format(domain,record_id))
+    if new_ip != result['target'] :
+        raise Exception("Error updating {}.{} with {}".format(subdomain,domain,new_ip))
+        
+        
+def delete_record(domain, subdomain, typ):
+    """
+    if it exists, delete an A or AAAA record  
+    (because the corresponding IP is not available)
+    """
+    print("checking record {} for {}.{}".format(typ,subdomain,domain))
+    result = client.get("/domain/zone/{}/record".format(domain),
+                        fieldType = typ,
+                        subDomain = subdomain
+                     )
+    if len(result) == 1:
+        # record exists, delete it
+        record_id = result[0]
+        print("### deleting record {} for {}.{}".format(typ,subdomain,domain))
+        client.delete("/domain/zone/{}/record/{}".format(domain,record_id))
+        client.post('/domain/zone/{}/refresh'.format(domain))
+
+
+#reload saved values
+try:
+    with open(current_ip_file, 'r') as f:
+        old_time, old_ipv4, old_ipv6   = json.load(f)
+except IOError:
+    print("No old ips recorded")
+
+current_ipv4 = get_current_ip(4)
+current_ipv6 = get_current_ip(6)
+print('current ips: {} ; {}'.format(current_ipv4, current_ipv6))
+
+if current_ipv4 or current_ipv6 : #we could get at least one address
+  try :
+    need_update = (old_ipv4 != current_ipv4) or (old_ipv6 != current_ipv6) or ((old_time - time.time()) > 3600.0 * checkDNS_interval_hrs)
+  except : #old values do not exist, we must check the records
+    need_update = True 
+  if need_update :
+    try :
+      for host in hosts :
+        domain = host["domain"]
+        subdomain = host ["subdomain"]
+        if ('ipv4' not in host) or (host['ipv4'] != False) :
+            if current_ipv4 :
+                ttl = default_ttl if ('ttl' not in host) else host['ttl']
+                update_record(domain, subdomain, current_ipv4, _ttl = ttl)
+            else :
+                delete_record(domain, subdomain, 'A')
+        else :
+            print("Not touching A record for {}.{}, as instructed".format(subdomain, domain))
+        if ('ipv6' not in host) or (host['ipv6'] != False) :
+            if current_ipv6 :
+                ttl = default_ttl if ('ttl' not in host) else host['ttl']
+                update_record(domain, subdomain, current_ipv6, _ttl = ttl)
+            else :
+                delete_record(domain, subdomain, 'AAAA')
+        else :
+            print("Not touching AAAA record for {}.{}, as instructed".format(subdomain, domain))
+          print ("changed , saving new ips: ",current_ipv4, " ", current_ipv6)
+      #all hosts records have been updated without errors, save current addresses    
+      with open(current_ip_file, 'w') as f:
+        json.dump([time.time(), current_ipv4, current_ipv6],f)
+    except Exception as e: #some error occured,
+      print("error updating records :", str(e))
+      pass
+  else :
+    print("do nothing")
+else :
+  print("cannot get IPs. Network down? Doing nothing")
+