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ovh-dns-updater/ovh-dns-updater.py
pj 6385e61768 other site for querying ips
2021-02-28 22:07:06 +01:00

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Python
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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()
# Should missing IP address being considered as error (Depend on the ISP, internet box settings...)?
# In case a required IP cannot be obtained, the script will send an email and stop without updating anything.
# If, for any reason, IPv4 or IPv6 address cannot be obtained and if it is not protected by this list, the corresponding records will be deleted for all hosts.
ip_versions_required = [4] # MUST not be empty. Can be [4],[6] or [4,6]
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 send_email(msg, sender = 'no_reply@mydomain.com', receiver = 'admin@mydomain.com') :
import smtplib
try :
smtpObj = smtplib.SMTP('localhost')
smtpObj.sendmail(sender, receiver,
"From: {}\nTo: {}\nSubject: DNS update problem\n\nThe ovh-dns-updater.py script reports:\n{}\n".format(sender, receiver, msg)
)
except smtplib.SMTPException:
print( timestamp()," : Error unable to send email")
def get_current_ip(v = 4):
#url = 'https://api6.ipify.org' if v == 6 else 'https://api.ipify.org' #frequent error on ipv6 https://github.com/rdegges/ipify-api/issues/54
url = 'https://v{}.ident.me'.format(v)
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)))
if v in ip_versions_required :
message = "{} : Cannot get required IPv{} because {} occurred. Failing".format(timestamp(), v, e)
print(message)
send_email (message)
quit()
else :
return False
if r.status_code == requests.codes.ok :
return r.text
elif v in ip_versions_required :
message = "{} : Cannot get required IPv{} : requests.get returned status_code {}. Failing".format(timestamp(), v, r.status_code)
print(message)
send_email (message)
quit()
else :
return False
def timestamp() :
return time.asctime( time.localtime(time.time()) )
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:
#creating NEW record
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]
records_changed += 1
print("{} : ### created new record {} for {}.{}".format(timestamp(),typ,subdomain,domain))
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))
records_changed += 1
#checking changes
result = client.get("/domain/zone/{}/record/{}".format(domain,record_id))
if new_ip != result['target'] :
records_changed -= 1
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(timestamp(),typ,subdomain,domain))
client.delete("/domain/zone/{}/record/{}".format(domain,record_id))
client.post('/domain/zone/{}/refresh'.format(domain))
records_changed += 1
current_ipv4 = get_current_ip(4)
current_ipv6 = get_current_ip(6)
#print('current ips: {} ; {}'.format(current_ipv4, current_ipv6))
#reload saved values & compare
try:
with open(current_ip_file, 'r') as f:
old_time, old_ipv4, old_ipv6 = json.load(f)
need_update = (old_ipv4 != current_ipv4) or (old_ipv6 != current_ipv6) or ((old_time - time.time()) > 3600.0 * checkDNS_interval_hrs)
except IOError:
#print("No old ips recorded")
need_update = True
if need_update :
records_changed = 0
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))
pass
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))
pass
#all hosts records have been updated without errors, log change and save current addresses
print("{} : new addresses {} ; {} -- {} records updates".format(timestamp(), current_ipv4, current_ipv6, records_changed))
with open(current_ip_file, 'w') as f:
json.dump([time.time(), current_ipv4, current_ipv6],f)
except Exception as e: #some error occured (API down, keys expired...?),
msg = "{} : ### error {} while updating records!! {} records updated with new addresses {} ; {}".format(timestamp(), str(e), records_changed, current_ipv4, current_ipv6)
print(msg)
send_email(msg)
# not saving new addresses, so that update is attempted again.
else :
#print("nothing to do!")
pass
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