From 8be0de7a0ff28e02cd76482f7b51858ead10f9cf Mon Sep 17 00:00:00 2001
From: Girts Folkmanis <girtsf@users.noreply.github.com>
Date: Tue, 23 Oct 2018 17:08:32 -0700
Subject: [PATCH] add retries to get_ip()
Instead of failing immediately if getting local IP address fails, we try
up to configured number of times, increasing the delay every time.
---
config-template.txt | 4 ++++
gandi_ddns.py | 48 ++++++++++++++++++++++++++++++++++-----------
2 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/config-template.txt b/config-template.txt
index 82ac92b..fb46cff 100644
--- a/config-template.txt
+++ b/config-template.txt
@@ -14,3 +14,7 @@ ttl = 900
# Production API
api = https://dns.api.gandi.net/api/v5/
+
+# Number of retries for looking up our own IP address, since
+# the service seems to be flaky sometimes.
+retries = 3
diff --git a/gandi_ddns.py b/gandi_ddns.py
index dcf6bd3..170a41f 100755
--- a/gandi_ddns.py
+++ b/gandi_ddns.py
@@ -5,30 +5,55 @@ import requests
import json
import ipaddress
from datetime import datetime
+import time
config_file = "config.txt"
SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
+DEFAULT_RETRIES = 3
-def get_ip():
+
+class GandiDdnsError(Exception):
+ pass
+
+
+def get_ip_inner():
#Get external IP
try:
- # Could be any service that just gives us a simple raw ASCII IP address (not HTML etc)
- r = requests.get('https://api.ipify.org', timeout=3)
- except Exception:
- print('Failed to retrieve external IP.')
- sys.exit(2)
+ # Could be any service that just gives us a simple raw ASCII IP address (not HTML etc)
+ r = requests.get('https://api.ipify.org', timeout=3)
+ except requests.exceptions.RequestException:
+ raise GandiDdnsError('Failed to retrieve external IP.')
if r.status_code != 200:
- print(('Failed to retrieve external IP. Server responded with status_code: %d' % r.status_code))
- sys.exit(2)
+ raise GandiDdnsError(
+ 'Failed to retrieve external IP.'
+ ' Server responded with status_code: %d' % r.status_code)
ip = r.text.rstrip() # strip \n and any trailing whitespace
if not(ipaddress.IPv4Address(ip)): # check if valid IPv4 address
- sys.exit(2)
+ raise GandiDdnsError('Got invalid IP: ' + ip)
return ip
+
+def get_ip(retries):
+ #Get external IP with retries
+
+ # Start at 5 seconds, double on every retry.
+ retry_delay_time = 5
+ for attempt in range(retries):
+ try:
+ return get_ip_inner()
+ except GandiDdnsError as e:
+ print('Getting external IP failed: %s' % e)
+ print('Waiting for %d seconds before trying again' % retry_delay_time)
+ time.sleep(retry_delay_time)
+ # Double retry time, cap at 60s.
+ retry_delay_time = min(60, 2 * retry_delay_time)
+ print('Exhausted retry attempts')
+ sys.exit(2)
+
def read_config(config_path):
#Read configuration file
cfg = configparser.ConfigParser()
@@ -75,7 +100,8 @@ def main():
url = '%sdomains/%s/records/%s/A' % (config.get(section, 'api'), config.get(section, 'domain'), config.get(section, 'a_name'))
print(url)
#Discover External IP
- external_ip = get_ip()
+ retries = config.get(section, 'retries', fallback=DEFAULT_RETRIES)
+ external_ip = get_ip(retries)
print(('External IP is: %s' % external_ip))
#Prepare record
@@ -95,4 +121,4 @@ def main():
update_record(url, headers, payload)
if __name__ == "__main__":
- main()
\ No newline at end of file
+ main()
--
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