Adding retry logic for #655 and add tests for delete_default_vpc.py (#…

…708)

* Adding retry logic for #655 and add tests for delete_default_vpc.py

* Proper logging

* Adopt tenacity in favor of retrying

* Max retry logic and exponential backoff intervals

* Change logging msg to DEBUG and add meaningfull msg

* Mock nap.time.sleep for faster tests

* Update src/lambda_codebase/account_processing/tests/test_delete_default_vpc.py

---------

Co-authored-by: Javy de Koning
Co-authored-by: Stewart Wallace
Co-authored-by: Simon Kok

src/lambda_codebase/account_processing/delete_default_vpc.py

@@ -5,7 +5,10 @@
 Deletes the default VPC in a particular region
 """
 import os
+
 from aws_xray_sdk.core import patch_all
+from botocore.exceptions import ClientError
+import tenacity
 
 # ADF imports
 from logger import configure_logger
@@ -25,12 +28,25 @@ def assume_role(account_id):
         "adf_delete_default_vpc",
     )
 
-
+@tenacity.retry(
+    retry=tenacity.retry_if_exception_type(ClientError),
+    # Fail after 180 Sec of retrying
+    stop=tenacity.stop_after_delay(180),
+    # Wait 2^x * 1 second between each retry starting with 4s, max 10s intervals
+    wait=tenacity.wait_exponential(multiplier=1, min=4, max=10),
+)
 def find_default_vpc(ec2_client):
-    vpc_response = ec2_client.describe_vpcs()
-    for vpc in vpc_response["Vpcs"]:
-        if vpc["IsDefault"] is True:
-            return vpc["VpcId"]
+    try:
+        vpc_response = ec2_client.describe_vpcs()
+        for vpc in vpc_response["Vpcs"]:
+            if vpc.get("IsDefault", False):
+                return vpc["VpcId"]
+    except ClientError as error:
+        LOGGER.debug(
+            "An error occurred while describing VPCs: %s", error
+        )
+        raise
+    # If no default VPC found, return None
     return None
 
 

src/lambda_codebase/account_processing/requirements.txt

@@ -1,2 +1,3 @@
 aws-xray-sdk==2.13.0
 pyyaml~=6.0.1
+tenacity==8.2.3

src/lambda_codebase/account_processing/tests/__init__.py

@@ -2,3 +2,12 @@
 # SPDX-License-Identifier: MIT-0
 
 # pylint: skip-file
+
+"""
+__init__ for tests module
+"""
+
+import sys
+import os
+
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))

src/lambda_codebase/account_processing/tests/test_delete_default_vpc.py

@@ -0,0 +1,48 @@
+# Copyright Amazon.com Inc. or its affiliates.
+# SPDX-License-Identifier: MIT-0
+
+"""
+Tests the delete_default_vpc lambda
+"""
+
+import unittest
+from unittest.mock import MagicMock, patch
+from delete_default_vpc import find_default_vpc
+from botocore.exceptions import ClientError
+
+
+class TestFindDefaultVPC(unittest.TestCase):
+
+    @patch("tenacity.nap.time.sleep", MagicMock())
+    @patch('delete_default_vpc.patch_all')
+    # pylint: disable=unused-argument
+    def test_find_default_vpc(self, mock_patch_all):
+        # Create a mock ec2_client
+        mock_ec2_client = MagicMock()
+
+        # Define the side effects for describe_vpcs method
+        side_effects = [
+            ClientError({'Error': {'Code': 'MockTestError'}}, 'describe_vpcs'),
+            ClientError({'Error': {'Code': 'MockTestError'}}, 'describe_vpcs'),
+            {"Vpcs": [
+                {"VpcId": "vpc-123", "IsDefault": False},
+                {"VpcId": "vpc-456", "IsDefault": True},
+                {"VpcId": "vpc-789", "IsDefault": False}
+            ]}
+        ]
+
+        # Set side_effect for the mock ec2_client.describe_vpcs
+        mock_ec2_client.describe_vpcs.side_effect = side_effects
+
+        # Call the function with the mock ec2_client
+        default_vpc_id = find_default_vpc(mock_ec2_client)
+
+        # Check if the correct default VPC ID is returned
+        self.assertEqual(default_vpc_id, "vpc-456")
+
+        # Check if describe_vpcs method is called 3 times
+        self.assertEqual(mock_ec2_client.describe_vpcs.call_count, 3)
+
+
+if __name__ == '__main__':
+    unittest.main()