From eac963f25de08a10d42be2dcf6da75cacc6ad240 Mon Sep 17 00:00:00 2001
From: Shannon Byrnes <sbyrnes@internet2.edu>
Date: Sun, 17 Mar 2024 18:47:47 -0700
Subject: [PATCH] wip

---
 lab-2/4_netmiko_seek_helper_addrs.py | 41 ++++++++++++++++------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/lab-2/4_netmiko_seek_helper_addrs.py b/lab-2/4_netmiko_seek_helper_addrs.py
index 9caf730..3d8663c 100644
--- a/lab-2/4_netmiko_seek_helper_addrs.py
+++ b/lab-2/4_netmiko_seek_helper_addrs.py
@@ -6,6 +6,7 @@
 password = "clab@123"
 device_type = "cisco_xr"
 hosts = ["172.16.x.2", "172.16.x.3", "172.16.x.4"]  # TODO
+old_ip_helper = "fill me in!"  # TODO
 target_ip_helper = "fill me in!"  # TODO
 
 for host in hosts:
@@ -28,27 +29,31 @@
         print(f"Inspecting {intf_name} on {host}...")
 
         # Retrieve the helper address, if it exists.
-        helper_address_line = intf.re_search_children("^ ipv4 helper-address")
+        helper_address_line = intf.re_search_children(f"^ ipv4 helper-address .* {old_ip_helper}")
         if not helper_address_line:
             # Nothing to see here! Skip.
-            # Don't configure a new IP helper on interfaces that don't have one.
+            # Only configure our new IP helper on the interface if the old one existed.
             continue
-
-        # Get the last "word" in the line, which is the helper IP address.
-        ip = helper_address_line[-1].text
-
-        if ip != target_ip_helper:
+        else:
             print(f"Found old IP helper!:\n{intf}")
-            commands = [
-                intf_name,
-                f"no ipv4 helper-address {ip}",
-                f"ipv4 helper-address {target_ip_helper}",
-                "commit"
-            ]
-            # Let's observe:
-            print(f"Running: {commands}")
-            connection.send_config_set(commands)
-            print(f"Running: show run int {intf_name}")
-            print(connection.send_command(f"show run int {intf_name}"))
+
+        # Variable `helper_address_line` is a list of all matching lines.
+        # We know Cisco won't have duplicate lines, so we can always assume it is the first
+        # in the list.
+        raw_config_line = helper_address_line[0].text
+
+        # We only need the last "word" in the line, which is the IP address.
+        ip = raw_config_line.split()[-1]
+
+        commands = [
+            intf_name,
+            f"no ipv4 helper-address {ip}",
+            f"ipv4 helper-address {target_ip_helper}",
+            "commit"
+        ]
+        # Let's observe:
+        print(f"Before:\n{connection.send_command(f'show run {intf_name}')}\n")
+        connection.send_config_set(commands)
+        print(f"After:\n{connection.send_command(f'show run {intf_name}')}")
 
 print("Done!")