From 4809ea985869b39636dfdaf4e556caecc5cabd54 Mon Sep 17 00:00:00 2001
From: Pedro Escaleira <escaleira@av.it.pt>
Date: Mon, 21 Mar 2022 17:54:45 +0000
Subject: [PATCH] Bug 1938 fixed: : added a random suffix to the end of the
 Juju app name, in order to allow multiple Juju charms per VDU

I followed the second option of the bug's description. Now, Juju
applications have a random suffix with size=5 (the random suffix
size used by K8s), in order to avoid collisions between applications'
names;

Also fixed unit-test on test_n2vc_juju_conn.py

Change-Id: I53195113de8a3c4f04792742001e3d2a356b4dfd
Signed-off-by: Pedro Escaleira <escaleira@av.it.pt>
---
 n2vc/n2vc_juju_conn.py                 | 10 ++++++++--
 n2vc/tests/unit/test_n2vc_juju_conn.py | 10 ++++++++--
 n2vc/utils.py                          | 14 ++++++++++++++
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/n2vc/n2vc_juju_conn.py b/n2vc/n2vc_juju_conn.py
index c01c436..3f6a501 100644
--- a/n2vc/n2vc_juju_conn.py
+++ b/n2vc/n2vc_juju_conn.py
@@ -38,6 +38,7 @@ from n2vc.n2vc_conn import N2VCConnector
 from n2vc.n2vc_conn import obj_to_dict, obj_to_yaml
 from n2vc.libjuju import Libjuju
 from n2vc.store import MotorStore
+from n2vc.utils import generate_random_alfanum_string
 from n2vc.vca.connection import get_connection
 from retrying_async import retry
 
@@ -1167,7 +1168,7 @@ class N2VCJujuConnector(N2VCConnector):
         """
         Build application name from namespace
         :param namespace:
-        :return: app-vnf-<vnf id>-vdu-<vdu-id>-cnt-<vdu-count>
+        :return: app-vnf-<vnf id>-vdu-<vdu-id>-cnt-<vdu-count>-<random_value>
         """
 
         # TODO: Enforce the Juju 50-character application limit
@@ -1194,7 +1195,12 @@ class N2VCJujuConnector(N2VCConnector):
         else:
             vdu_count = "-cnt-" + vdu_count
 
-        application_name = "app-{}{}{}".format(vnf_id, vdu_id, vdu_count)
+        # Generate a random suffix with 5 characters (the default size used by K8s)
+        random_suffix = generate_random_alfanum_string(size=5)
+
+        application_name = "app-{}{}{}-{}".format(
+            vnf_id, vdu_id, vdu_count, random_suffix
+        )
 
         return N2VCJujuConnector._format_app_name(application_name)
 
diff --git a/n2vc/tests/unit/test_n2vc_juju_conn.py b/n2vc/tests/unit/test_n2vc_juju_conn.py
index d89de3f..9365106 100644
--- a/n2vc/tests/unit/test_n2vc_juju_conn.py
+++ b/n2vc/tests/unit/test_n2vc_juju_conn.py
@@ -16,6 +16,7 @@
 import asyncio
 import logging
 from unittest.mock import Mock
+from unittest.mock import patch
 
 
 import asynctest
@@ -143,8 +144,13 @@ class K8sProxyCharmsTest(N2VCJujuConnTestCase):
         self.n2vc.libjuju.deploy_charm = AsyncMock()
         self.n2vc.libjuju.model_exists.return_value = False
 
+    @patch(
+        "n2vc.n2vc_juju_conn.generate_random_alfanum_string",
+        **{"return_value": "random"}
+    )
     def test_success(
         self,
+        mock_generate_random_alfanum_string,
         mock_path,
         mock_file_exists,
     ):
@@ -162,7 +168,7 @@ class K8sProxyCharmsTest(N2VCJujuConnTestCase):
         self.n2vc.libjuju.add_model.assert_called_once()
         self.n2vc.libjuju.deploy_charm.assert_called_once_with(
             model_name="ns-id-k8s",
-            application_name="app-vnf-vnf-id-vdu-vdu",
+            application_name="app-vnf-vnf-id-vdu-vdu-random",
             path="/path/path/",
             machine_id=None,
             db_dict={},
@@ -170,7 +176,7 @@ class K8sProxyCharmsTest(N2VCJujuConnTestCase):
             total_timeout=None,
             config=None,
         )
-        self.assertEqual(ee_id, "ns-id-k8s.app-vnf-vnf-id-vdu-vdu.k8s")
+        self.assertEqual(ee_id, "ns-id-k8s.app-vnf-vnf-id-vdu-vdu-random.k8s")
 
     def test_no_artifact_path(
         self,
diff --git a/n2vc/utils.py b/n2vc/utils.py
index 0dbd71e..5ac0e2c 100644
--- a/n2vc/utils.py
+++ b/n2vc/utils.py
@@ -16,6 +16,8 @@ import base64
 import re
 import binascii
 import yaml
+import string
+import secrets
 from enum import Enum
 from juju.machine import Machine
 from juju.application import Application
@@ -147,3 +149,15 @@ def obj_to_dict(obj: object) -> dict:
     yaml_text = obj_to_yaml(obj)
     # parse to dict
     return yaml.load(yaml_text, Loader=yaml.Loader)
+
+
+def generate_random_alfanum_string(size: int) -> str:
+    """
+    Generate random alfa-numeric string with a size given by argument
+    :param size:
+    :return: random generated string
+    """
+
+    return "".join(
+        secrets.choice(string.ascii_letters + string.digits) for i in range(size)
+    )
-- 
2.25.1