implement retries for ipify with backoff

add tests
crazystick · Mar 22, 2020 · 4eedf2d · 4eedf2d
1 parent 6b71483
commit 4eedf2d
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Showing 3 changed files with 188 additions and 29 deletions.
diff --git a/dynamic_cloud_dns_client.py b/dynamic_cloud_dns_client.py
@@ -2,18 +2,30 @@
 from time import sleep
 import logging
 import os
+import backoff
 
 logging.basicConfig(level=logging.DEBUG)
 logger = logging.getLogger(__name__)
 
-IPIFY4 = 'https://api.ipify.org?format=json'
-IPIFY6 = 'https://api6.ipify.org?format=json'
+IPIFY4 = 'https://api.ipify.org/?format=json'
+IPIFY6 = 'https://api6.ipify.org/?format=json'
 
+RETRIES = 5
+
+@backoff.on_exception(backoff.expo,
+                      (requests.exceptions.Timeout,
+                       requests.exceptions.ConnectionError),
+                      max_tries=RETRIES)
 def get_ipv4():
+    logger.debug("call ipv4")
     r = requests.get(IPIFY4)
     r.raise_for_status()
     return r.json()['ip']
 
+@backoff.on_exception(backoff.expo,
+                      (requests.exceptions.Timeout,
+                       requests.exceptions.ConnectionError),
+                      max_tries=RETRIES)
 def get_ipv6():
     r = requests.get(IPIFY6)
     r.raise_for_status()
@@ -41,39 +53,51 @@ def update_cloud_dns(ipv4=None, ipv6=None):
     logger.info("IP addresses updated: IPv4={} IPv6={}".format(ipv4, ipv6))
 
 
-if __name__ == "__main__":
-    current_ipv4 = None
-    current_ipv6 = None
+def do_update(current_ipv4, current_ipv6):
     ipv4 = None
     ipv6 = None
-
-    while True:
-        if os.environ['DCDNS_IPV4'] == 'YES':
-            try:
-                ipv4 = get_ipv4()
-                if ipv4 == current_ipv4:
-                    ipv4 = None
-                else:
-                    current_ipv4 = ipv4
-            except requests.exceptions.HTTPError:
+    retries = 1
+
+    if os.environ['DCDNS_IPV4'] == 'YES':
+        try:
+            ipv4 = get_ipv4()
+            if ipv4 == current_ipv4:
                 ipv4 = None
+            else:
+                current_ipv4 = ipv4
+        except (requests.exceptions.Timeout,
+            requests.exceptions.ConnectionError):
+            ipv4 = None
+        except requests.exceptions.HTTPError as err:
+            logger.exception(err)
 
-        if os.environ['DCDNS_IPV6'] == 'YES':
-            try:
-                ipv6 = get_ipv6()
-                if ipv6 == current_ipv6:
-                    ipv6 = None
-                else:
-                    current_ipv6 = ipv6
-            except requests.exceptions.HTTPError:
-                ipv6 = None
-
+    if os.environ['DCDNS_IPV6'] == 'YES':
         try:
-            update_cloud_dns(ipv4=ipv4, ipv6=ipv6)
-        except ValueError:
-            logger.info("No IP address updates")
+            ipv6 = get_ipv6()
+            if ipv6 == current_ipv6:
+                ipv6 = None
+            else:
+                current_ipv6 = ipv6
+        except (requests.exceptions.Timeout,
+            requests.exceptions.ConnectionError):
+            ipv6 = None
         except requests.exceptions.HTTPError as err:
             logger.exception(err)
 
-        sleep(int(os.environ['DCDNS_FREQUENCY']))
+    try:
+        update_cloud_dns(ipv4=ipv4, ipv6=ipv6)
+    except ValueError:
+        logger.info("No IP address updates")
+    except requests.exceptions.HTTPError as err:
+        logger.exception(err)
+
+    return current_ipv4, current_ipv6
+
+
+if __name__ == "__main__":
+    current_ipv4 = None
+    current_ipv6 = None
 
+    while True:
+        current_ipv4, current_ipv6 = do_update(current_ipv4, current_ipv6)
+        sleep(int(os.environ['DCDNS_FREQUENCY']))
diff --git a/requirements.txt b/requirements.txt
@@ -0,0 +1,4 @@
+requests
+backoff==1.10.0
+pytest
+requests-mock
diff --git a/test_client.py b/test_client.py
@@ -0,0 +1,131 @@
+
+from dynamic_cloud_dns_client import *
+
+def test_get_ipv4(requests_mock):
+	# given
+	requests_mock.get(IPIFY4, json={'ip': '0.0.0.0'})
+
+	# when
+	ip = get_ipv4()
+
+	# then
+	assert ip == '0.0.0.0'
+
+def test_get_ipv6(requests_mock):
+	# given
+	requests_mock.get(IPIFY6, json={'ip': '2001:0db8:0000:0000:0000:8a2e:0370:7334'})
+
+	# when
+	ip = get_ipv6()
+
+	# then
+	assert ip == '2001:0db8:0000:0000:0000:8a2e:0370:7334'
+
+def test_main_no_update(requests_mock, monkeypatch):
+	# given
+	monkeypatch.setenv("DCDNS_IPV4", "YES")
+	monkeypatch.setenv("DCDNS_IPV6", "YES")
+	monkeypatch.setenv("DCDNS_TOKEN", "TEST_TOKEN")
+	monkeypatch.setenv("DCDNS_HOST", "TEST_HOST")
+	monkeypatch.setenv("DCDNS_ZONE", "TEST_ZONE")
+	monkeypatch.setenv("DCDNS_FUNCTION_URL", "https://cloudfunctions.net.mock/updateHost")
+	requests_mock.get(IPIFY4, json={'ip': '0.0.0.0'})
+	requests_mock.get(IPIFY6, json={'ip': '2001:0db8:0000:0000:0000:8a2e:0370:7334'})
+	requests_mock.post("https://cloudfunctions.net.mock/updateHost")
+
+	# when
+	ipv4, ipv6 = do_update('0.0.0.0', '2001:0db8:0000:0000:0000:8a2e:0370:7334')
+
+	# then
+	assert ipv4 == '0.0.0.0'
+	assert ipv6 == '2001:0db8:0000:0000:0000:8a2e:0370:7334'
+	assert requests_mock.call_count == 2
+	assert requests_mock.request_history[0].url == IPIFY4
+	assert requests_mock.request_history[1].url == IPIFY6
+
+def test_main_does_update(requests_mock, monkeypatch):
+	# given
+	monkeypatch.setenv("DCDNS_IPV4", "YES")
+	monkeypatch.setenv("DCDNS_IPV6", "YES")
+	monkeypatch.setenv("DCDNS_TOKEN", "TEST_TOKEN")
+	monkeypatch.setenv("DCDNS_HOST", "TEST_HOST")
+	monkeypatch.setenv("DCDNS_ZONE", "TEST_ZONE")
+	monkeypatch.setenv("DCDNS_FUNCTION_URL", "https://cloudfunctions.net.mock/updateHost")
+	requests_mock.get(IPIFY4, json={'ip': '1.2.3.4'})
+	requests_mock.get(IPIFY6, json={'ip': '2001:0db8:9999:0000:0000:8a2e:0370:7334'})
+	requests_mock.post("https://cloudfunctions.net.mock/updateHost")
+
+	# when
+	ipv4, ipv6 = do_update('0.0.0.0', '2001:0db8:0000:0000:0000:8a2e:0370:7334')
+
+	# then
+	assert ipv4 == '1.2.3.4'
+	assert ipv6 == '2001:0db8:9999:0000:0000:8a2e:0370:7334'
+	assert requests_mock.call_count == 3
+	assert requests_mock.request_history[0].url == IPIFY4
+	assert requests_mock.request_history[1].url == IPIFY6
+	assert requests_mock.request_history[2].url == "https://cloudfunctions.net.mock/updateHost"
+
+def test_main_single_retry(requests_mock, monkeypatch):
+	# given
+	monkeypatch.setenv("DCDNS_IPV4", "YES")
+	monkeypatch.setenv("DCDNS_IPV6", "YES")
+	monkeypatch.setenv("DCDNS_TOKEN", "TEST_TOKEN")
+	monkeypatch.setenv("DCDNS_HOST", "TEST_HOST")
+	monkeypatch.setenv("DCDNS_ZONE", "TEST_ZONE")
+	monkeypatch.setenv("DCDNS_FUNCTION_URL", "https://cloudfunctions.net.mock/updateHost")
+	requests_mock.get(IPIFY4, [{'exc': requests.exceptions.ConnectTimeout},{'json': {'ip': '1.2.3.4'}}])
+	requests_mock.get(IPIFY6, json={'ip': '2001:0db8:9999:0000:0000:8a2e:0370:7334'})
+	requests_mock.post("https://cloudfunctions.net.mock/updateHost")
+
+	# when
+	ipv4, ipv6 = do_update('0.0.0.0', '2001:0db8:0000:0000:0000:8a2e:0370:7334')
+
+	# then
+	assert ipv4 == '1.2.3.4'
+	assert ipv6 == '2001:0db8:9999:0000:0000:8a2e:0370:7334'
+	assert requests_mock.call_count == 4
+	assert requests_mock.request_history[0].url == IPIFY4
+	assert requests_mock.request_history[1].url == IPIFY4
+	assert requests_mock.request_history[2].url == IPIFY6
+	assert requests_mock.request_history[3].url == "https://cloudfunctions.net.mock/updateHost"
+
+def test_main_max_retry(requests_mock, monkeypatch):
+	# given
+	monkeypatch.setenv("DCDNS_IPV4", "YES")
+	monkeypatch.setenv("DCDNS_IPV6", "YES")
+	monkeypatch.setenv("DCDNS_TOKEN", "TEST_TOKEN")
+	monkeypatch.setenv("DCDNS_HOST", "TEST_HOST")
+	monkeypatch.setenv("DCDNS_ZONE", "TEST_ZONE")
+	monkeypatch.setenv("DCDNS_FUNCTION_URL", "https://cloudfunctions.net.mock/updateHost")
+	requests_mock.get(IPIFY4, [
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout}])
+	requests_mock.get(IPIFY6, [
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout},
+		{'exc': requests.exceptions.ConnectTimeout}])
+	requests_mock.post("https://cloudfunctions.net.mock/updateHost")
+
+	# when
+	ipv4, ipv6 = do_update('0.0.0.0', '2001:0db8:0000:0000:0000:8a2e:0370:7334')
+
+	# then
+	assert ipv4 == '0.0.0.0'
+	assert ipv6 == '2001:0db8:0000:0000:0000:8a2e:0370:7334'
+	assert requests_mock.call_count == 10
+	assert requests_mock.request_history[0].url == IPIFY4
+	assert requests_mock.request_history[1].url == IPIFY4
+	assert requests_mock.request_history[2].url == IPIFY4
+	assert requests_mock.request_history[3].url == IPIFY4
+	assert requests_mock.request_history[4].url == IPIFY4
+	assert requests_mock.request_history[5].url == IPIFY6
+	assert requests_mock.request_history[6].url == IPIFY6
+	assert requests_mock.request_history[7].url == IPIFY6
+	assert requests_mock.request_history[8].url == IPIFY6
+	assert requests_mock.request_history[9].url == IPIFY6