Permit duplicate VNIs in templates with flag

Supports niche usecases whereby a network template should contain the
same VNI(s) more than once.

api-daemon/pvcapid/flaskapi.py

@@ -7139,7 +7139,11 @@ class API_Provisioner_Template_Network_Net_Root(Resource):
                 "name": "vni",
                 "required": True,
                 "helptext": "A valid VNI must be specified.",
-            }
+            },
+            {
+                "name": "permit_duplicate",
+                "required": False,
+            },
         ]
     )
     @Authenticator
@@ -7155,6 +7159,11 @@ class API_Provisioner_Template_Network_Net_Root(Resource):
             type: integer
             required: false
             description: PVC network VNI
+          - in: query
+            name: permit_duplicate
+            type: boolean
+            required: false
+            description: Bypass checks to permit duplicate VNIs for niche usecases
         responses:
           200:
             description: OK
@@ -7168,7 +7177,7 @@ class API_Provisioner_Template_Network_Net_Root(Resource):
               id: Message
         """
         return api_provisioner.create_template_network_element(
-            template, reqargs.get("vni", None)
+            template, reqargs.get("vni", None), reqargs.get("permit_duplicate", False)
         )
 
 
@@ -7206,13 +7215,27 @@ class API_Provisioner_Template_Network_Net_Element(Resource):
                 return _vni, 200
         abort(404)
 
+    @RequestParser(
+        [
+            {
+                "name": "permit_duplicate",
+                "required": False,
+            }
+        ]
+    )
     @Authenticator
-    def post(self, template, vni):
+    def post(self, template, vni, reqargs):
         """
         Create a new network {vni} in network template {template}
         ---
         tags:
           - provisioner / template
+        parameters:
+          - in: query
+            name: permit_duplicate
+            type: boolean
+            required: false
+            description: Bypass checks to permit duplicate VNIs for niche usecases
         responses:
           200:
             description: OK
@@ -7225,7 +7248,9 @@ class API_Provisioner_Template_Network_Net_Element(Resource):
               type: object
               id: Message
         """
-        return api_provisioner.create_template_network_element(template, vni)
+        return api_provisioner.create_template_network_element(
+            template, vni, reqargs.get("permit_duplicate", False)
+        )
 
     @Authenticator
     def delete(self, template, vni):

api-daemon/pvcapid/provisioner.py

@@ -284,12 +284,13 @@ def create_template_network(name, mac_template=None):
     return retmsg, retcode
 
 
-def create_template_network_element(name, vni):
+def create_template_network_element(name, vni, permit_duplicate=False):
     if list_template_network(name, is_fuzzy=False)[-1] != 200:
         retmsg = {"message": 'The network template "{}" does not exist.'.format(name)}
         retcode = 400
         return retmsg, retcode
 
+    if not permit_duplicate:
         networks, code = list_template_network_vnis(name)
         if code != 200:
             networks = []

client-cli/pvc/cli/cli.py

@@ -4849,13 +4849,27 @@ def cli_provisioner_template_network_vni():
 @connection_req
 @click.argument("name")
 @click.argument("vni")
-def cli_provisioner_template_network_vni_add(name, vni):
+@click.option(
+    "-d",
+    "--permit-duplicate",
+    "permit_duplicate_flag",
+    is_flag=True,
+    default=False,
+    help="Permit a duplicate VNI if one already exists",
+)
+def cli_provisioner_template_network_vni_add(name, vni, permit_duplicate_flag):
     """
     Add a new network VNI to network template NAME.
 
     Networks will be added to VMs in the order they are added and displayed within the template.
+
+    NOTE: Normally, the API prevents duplicate VNIs from being added to the same network template
+    by returning an error, as this requirement is very niche. If you do not desire this behaviour,
+    use the "-d"/"--permit-duplicate" option to bypass the check.
     """
     params = dict()
+    if permit_duplicate_flag:
+        params["permit_duplicate"] = True
 
     retcode, retdata = pvc.lib.provisioner.template_element_add(
         CLI_CONFIG, name, vni, params, element_type="net", template_type="network"