Add simple DNS probes

test/Dockerfile

 FROM debian:stable
 
 RUN apt-get -q update && env DEBIAN_FRONTEND=noninteractive \
-    apt-get install --no-install-recommends -y python3 python3-pip python3-setuptools python3-yaml python3-jinja2 python3-nose
+    apt-get install --no-install-recommends -y python3 python3-pip python3-setuptools python3-yaml python3-jinja2 python3-nose python3-dnspython
 
 ADD . /src
 WORKDIR /src

test/float_integration_test/__init__.py

@@ -52,6 +52,11 @@ class TestBase(unittest.TestCase):
         host = random.choice(hosts_in_group('frontend'))
         return ANSIBLE_VARS['hostvars'][host]['ip']
 
+    def all_frontend_ips(self):
+        """Return all IPs in the 'frontend' group."""
+        return [ANSIBLE_VARS['hostvars'][x]['ip']
+                for x in hosts_in_group('frontend')]
+
     def sso_conversation(self, sso_username=None, sso_password=None):
         url = _ansible_eval(
             '{{ sso_server_url | default("https://login." + domain_public[0]) }}')

test/float_integration_test/test_system.py

 import json
 import time
 import unittest
+from dns.resolver import Resolver
 from float_integration_test import TestBase, ANSIBLE_VARS
 
 
@@ -34,6 +35,26 @@ class TestHTTPRouter(URLTestBase):
         self.assertTrue(UNKNOWN_DOMAIN_MSG in result['body'])
 
 
+class TestDNS(TestBase):
+
+    def setUp(self):
+        self.resolver = Resolver(configure=False)
+        self.resolver.nameservers = self.all_frontend_ips()
+
+    def test_public_dns_entries_for_services(self):
+        frontend_ips = set(self.all_frontend_ips())
+        for service in ANSIBLE_VARS['services'].values():
+            for pe in service.get('public_endpoints', []):
+                if pe.get('skip_dns', False):
+                    continue
+                name = '%s.%s' % (pe['name'],
+                                  ANSIBLE_VARS['domain_public'][0])
+                print(f'querying {name}')
+                resp = self.resolver.query(name, 'A')
+                for record in resp:
+                    self.assertTrue(str(record) in frontend_ips)
+
+
 class TestBuiltinServiceURLs(URLTestBase):
     """Verify that all the public_endpoints are reachable.
 

test/setup.py

@@ -11,7 +11,7 @@ setup(
     url="https://git.autistici.org/ai3/float",
     install_requires=["Jinja2",
                       "PyYAML",
-                      ],
+                      "dnspython"],
     setup_requires=[],
     zip_safe=True,
     packages=find_packages(),