fix(snmp): limit SNMP communities

As Sonic devices do not accept more than one SNMP community, we prefer to limit to the lowest
common denominator.

netbox_cmdb/netbox_cmdb/constants.py

@@ -1,2 +1,5 @@
 BGP_MIN_ASN = 1
 BGP_MAX_ASN = 4294967294
+
+# As Sonic device don't support more than 1 community
+MAX_COMMUNITY_PER_DEVICE = 1

netbox_cmdb/netbox_cmdb/forms.py

@@ -7,6 +7,7 @@
 from django.utils.translation import gettext as _
 from extras.models import Tag
 from netbox_cmdb.models.snmp import SNMP, SNMPCommunity
+from netbox_cmdb.constants import MAX_COMMUNITY_PER_DEVICE
 from utilities.forms import DynamicModelMultipleChoiceField
 from utilities.forms.fields import DynamicModelChoiceField, MultipleChoiceField
 
@@ -93,6 +94,14 @@ class Meta:
         model = SNMP
         fields = ["device", "community_list", "location", "contact"]
 
+    def clean_community_list(self):
+        community_list = self.cleaned_data.get("community_list")
+        if len(community_list) > MAX_COMMUNITY_PER_DEVICE:
+            raise forms.ValidationError(
+                f"You cannot select more than {MAX_COMMUNITY_PER_DEVICE} SNMP Communities."
+            )
+        return community_list
+
 
 class SNMPCommunityGroupForm(NetBoxModelForm):
     class Meta: