monitoring: T4746: Add exception if we do not have firewall rules

Telegraf checks the firewall table 'vyos_filter' but it we don't
have any firewall in the system we don't have this table by default
It cause commit error for "service monitoring"
Add exception if the table "vyos_filter" is not found

1 files changed, 5 insertions, 1 deletions

diff --git a/src/conf_mode/service_monitoring_telegraf.py b/src/conf_mode/service_monitoring_telegraf.py
index 427cb6911..aafece47a 100755
--- a/src/conf_mode/service_monitoring_telegraf.py
+++ b/src/conf_mode/service_monitoring_telegraf.py
@@ -42,7 +42,11 @@ systemd_override = '/etc/systemd/system/telegraf.service.d/10-override.conf'
 
 def get_nft_filter_chains():
     """ Get nft chains for table filter """
-    nft = cmd('nft --json list table ip vyos_filter')
+    try:
+        nft = cmd('nft --json list table ip vyos_filter')
+    except Exception:
+        print('nft table ip vyos_filter not found')
+        return []
     nft = json.loads(nft)
     chain_list = []