Refactor of DNS resolving

Author: mzbroch

netbox_onboarding/helpers.py

@@ -0,0 +1,52 @@
+"""OnboardingTask Django model.
+
+(c) 2020 Network To Code
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+  http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+import socket
+
+import netaddr
+from netaddr.core import AddrFormatError
+
+from .exceptions import OnboardException
+
+
+def onboarding_task_fqdn_to_ip(ot):
+    """Method to assure OT has FQDN resolved to IP address and rewritten into OT.
+
+    If it is a DNS name, attempt to resolve the DNS address and assign the IP address to the
+    name.
+
+    Returns:
+        None
+
+    Raises:
+      OnboardException("fail-general"):
+        When a prefix was entered for an IP address
+      OnboardException("fail-dns"):
+        When a Name lookup via DNS fails to resolve an IP address
+    """
+    try:
+        # If successful, this is an IP address and can pass
+        netaddr.IPAddress(ot.ip_address)
+    # Raise an Exception for Prefix values
+    except ValueError:
+        raise OnboardException(reason="fail-general", message=f"ERROR appears a prefix was entered: {ot.ip_address}")
+    # An AddrFormatError exception means that there is not an IP address in the field, and should continue on
+    except AddrFormatError:
+        try:
+            # Perform DNS Lookup
+            ot.ip_address = socket.gethostbyname(ot.ip_address)
+            ot.save()
+        except socket.gaierror:
+            # DNS Lookup has failed, Raise an exception for unable to complete DNS lookup
+            raise OnboardException(reason="fail-dns", message=f"ERROR failed to complete DNS lookup: {ot.ip_address}")

netbox_onboarding/netdev_keeper.py

@@ -16,11 +16,9 @@
 import logging
 import socket
 
-import netaddr
 from django.conf import settings
 from napalm import get_network_driver
 from napalm.base.exceptions import ConnectionException, CommandErrorException
-from netaddr.core import AddrFormatError
 from netmiko.ssh_autodetect import SSHDetect
 from netmiko.ssh_exception import NetMikoAuthenticationException
 from netmiko.ssh_exception import NetMikoTimeoutException
@@ -96,46 +94,6 @@ def __init__(  # pylint: disable=R0913
         self.onboarding_class = StandaloneOnboarding
         self.driver_addon_result = None
 
-    def check_ip(self):
-        """Method to check if the IP address form field was an IP address.
-
-        If it is a DNS name, attempt to resolve the DNS address and assign the IP address to the
-        name.
-
-        Returns:
-            (bool): True if the IP address is an IP address, or a DNS entry was found and
-                    reassignment of the ot.ip_address was done.
-                    False if unable to find a device IP (error)
-
-        Raises:
-          OnboardException("fail-general"):
-            When a prefix was entered for an IP address
-          OnboardException("fail-dns"):
-            When a Name lookup via DNS fails to resolve an IP address
-        """
-        try:
-            # Assign checked_ip to None for error handling
-            # If successful, this is an IP address and can pass
-            checked_ip = netaddr.IPAddress(self.hostname)
-            return True
-        # Catch when someone has put in a prefix address, raise an exception
-        except ValueError:
-            raise OnboardException(
-                reason="fail-general", message=f"ERROR appears a prefix was entered: {self.hostname}"
-            )
-        # An AddrFormatError exception means that there is not an IP address in the field, and should continue on
-        except AddrFormatError:
-            try:
-                # Do a lookup of name to get the IP address to connect to
-                checked_ip = socket.gethostbyname(self.hostname)
-                self.hostname = checked_ip
-                return True
-            except socket.gaierror:
-                # DNS Lookup has failed, Raise an exception for unable to complete DNS lookup
-                raise OnboardException(
-                    reason="fail-dns", message=f"ERROR failed to complete DNS lookup: {self.hostname}"
-                )
-
     def check_reachability(self):
         """Ensure that the device at the mgmt-ipaddr provided is reachable.
 
@@ -231,9 +189,6 @@ def get_onboarding_facts(self):
           OnboardException('fail-general'):
             Any other unexpected device comms failure.
         """
-        # Check to see if the IP address entered was an IP address or a DNS entry, get the IP address
-        self.check_ip()
-
         self.check_reachability()
 
         logger.info("COLLECT: device information %s", self.hostname)

netbox_onboarding/tests/test_netdev_keeper.py

@@ -19,8 +19,8 @@
 from dcim.models import Site, DeviceRole, Platform
 
 from netbox_onboarding.exceptions import OnboardException
+from netbox_onboarding.helpers import onboarding_task_fqdn_to_ip
 from netbox_onboarding.models import OnboardingTask
-from netbox_onboarding.netdev_keeper import NetdevKeeper
 
 
 class NetdevKeeperTestCase(TestCase):
@@ -46,37 +46,32 @@ def setUp(self):
             ip_address="192.0.2.1/32", site=self.site1, role=self.device_role1, platform=self.platform1
         )
 
-    @mock.patch("netbox_onboarding.netdev_keeper.socket.gethostbyname")
+    @mock.patch("netbox_onboarding.helpers.socket.gethostbyname")
     def test_check_ip(self, mock_get_hostbyname):
         """Check DNS to IP address."""
         # Look up response value
         mock_get_hostbyname.return_value = "192.0.2.1"
 
-        # Create a Device Keeper object of the device
-        ndk4 = NetdevKeeper(hostname=self.onboarding_task4.ip_address)
-
-        # Check that the IP address is returned
-        self.assertTrue(ndk4.check_ip())
+        # FQDN -> IP
+        onboarding_task_fqdn_to_ip(ot=self.onboarding_task4)
 
         # Run the check to change the IP address
-        self.assertEqual(ndk4.hostname, "192.0.2.1")
+        self.assertEqual(self.onboarding_task4.ip_address, "192.0.2.1")
 
-    @mock.patch("netbox_onboarding.netdev_keeper.socket.gethostbyname")
+    @mock.patch("netbox_onboarding.helpers.socket.gethostbyname")
     def test_failed_check_ip(self, mock_get_hostbyname):
         """Check DNS to IP address failing."""
         # Look up a failed response
         mock_get_hostbyname.side_effect = gaierror(8)
-        ndk5 = NetdevKeeper(hostname=self.onboarding_task5.ip_address)
-        ndk7 = NetdevKeeper(hostname=self.onboarding_task7.ip_address)
 
         # Check for bad.local raising an exception
         with self.assertRaises(OnboardException) as exc_info:
-            ndk5.check_ip()
+            onboarding_task_fqdn_to_ip(ot=self.onboarding_task5)
             self.assertEqual(exc_info.exception.message, "ERROR failed to complete DNS lookup: bad.local")
             self.assertEqual(exc_info.exception.reason, "fail-dns")
 
         # Check for exception with prefix address entered
         with self.assertRaises(OnboardException) as exc_info:
-            ndk7.check_ip()
+            onboarding_task_fqdn_to_ip(ot=self.onboarding_task7)
             self.assertEqual(exc_info.exception.reason, "fail-prefix")
             self.assertEqual(exc_info.exception.message, "ERROR appears a prefix was entered: 192.0.2.1/32")

netbox_onboarding/worker.py

@@ -22,6 +22,7 @@
 from .choices import OnboardingFailChoices
 from .choices import OnboardingStatusChoices
 from .exceptions import OnboardException
+from .helpers import onboarding_task_fqdn_to_ip
 from .metrics import onboardingtask_results_counter
 from .models import OnboardingDevice
 from .models import OnboardingTask
@@ -43,6 +44,9 @@ def onboard_device(task_id, credentials):  # pylint: disable=too-many-statements
 
     ot = OnboardingTask.objects.get(id=task_id)
 
+    # Rewrite FQDN to IP for Onboarding Task
+    onboarding_task_fqdn_to_ip(ot)
+
     logger.info("START: onboard device")
     onboarded_device = None