fix: Update support for DeadLetterConfig (#134)

**Description:**
This PR adds the missing update feature for `DeadLetterConfig` property in Function resource. 

**Acknowledgement:**
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Author: Vandita2020

apis/v1alpha1/ack-generate-metadata.yaml

@@ -1,5 +1,5 @@
 ack_generate_info:
-  build_date: "2024-04-16T16:52:09Z"
+  build_date: "2024-04-16T23:40:41Z"
   build_hash: 37f4ba2b5a121a8786bc516e9ec4aa0b8b590c7d
   go_version: go1.21.6
   version: v0.33.0-1-g37f4ba2

pkg/resource/function/hooks.go

@@ -162,6 +162,15 @@ func (rm *resourceManager) updateFunctionConfiguration(
 		FunctionName: aws.String(*dspec.Name),
 	}
 
+	if delta.DifferentAt("Spec.DeadLetterConfig") {
+		deadLetterConfig := &svcsdk.DeadLetterConfig{}
+		if dspec.DeadLetterConfig != nil {
+			deadLetterConfigCopy := dspec.DeadLetterConfig.DeepCopy()
+			deadLetterConfig.TargetArn = deadLetterConfigCopy.TargetARN
+		}
+		input.DeadLetterConfig = deadLetterConfig
+	}
+
 	if delta.DifferentAt("Spec.Description") {
 		if dspec.Description != nil {
 			input.Description = aws.String(*dspec.Description)

test/e2e/resources/function_features.yaml

@@ -0,0 +1,17 @@
+apiVersion: lambda.services.k8s.aws/v1alpha1
+kind: Function
+metadata:
+  name: $FUNCTION_NAME
+  annotations:
+    services.k8s.aws/region: $AWS_REGION
+spec:
+  name: $FUNCTION_NAME
+  code:
+    s3Bucket: $BUCKET_NAME
+    s3Key: $LAMBDA_FILE_NAME
+  role: $LAMBDA_ROLE
+  runtime: python3.9
+  handler: main
+  deadLetterConfig:
+    targetARN: $DEAD_LETTER_CONFIG_TARGET_ARN
+  description: function created by ACK lambda-controller e2e tests

test/e2e/tests/test_function.py

@@ -604,6 +604,67 @@ def test_function_architecture(self, lambda_client):
         # Check Lambda function doesn't exist
         assert not lambda_validator.function_exists(resource_name)
 
+    def test_function_features(self, lambda_client):
+        resource_name = random_suffix_name("functionfeatures", 24)
+
+        resources = get_bootstrap_resources()
+        logging.debug(resources)
+
+        replacements = REPLACEMENT_VALUES.copy()
+        replacements["FUNCTION_NAME"] = resource_name
+        replacements["BUCKET_NAME"] = resources.FunctionsBucket.name
+        replacements["LAMBDA_ROLE"] = resources.EICRole.arn
+        replacements["LAMBDA_FILE_NAME"] = LAMBDA_FUNCTION_FILE_ZIP
+        replacements["AWS_REGION"] = get_region()
+        replacements["DEAD_LETTER_CONFIG_TARGET_ARN"] = resources.EICQueueOnSuccess.arn
+
+        # Load Lambda CR
+        resource_data = load_lambda_resource(
+            "function_features",
+            additional_replacements=replacements,
+        )
+        logging.debug(resource_data)
+
+        # Create k8s resource
+        ref = k8s.CustomResourceReference(
+            CRD_GROUP, CRD_VERSION, RESOURCE_PLURAL,
+            resource_name, namespace="default",
+        )
+        k8s.create_custom_resource(ref, resource_data)
+        cr = k8s.wait_resource_consumed_by_controller(ref)
+
+        assert cr is not None
+        assert k8s.get_resource_exists(ref)
+
+        time.sleep(CREATE_WAIT_AFTER_SECONDS)
+
+        cr = k8s.wait_resource_consumed_by_controller(ref)
+
+        lambda_validator = LambdaValidator(lambda_client)
+
+        # Check Lambda function exists
+        assert lambda_validator.function_exists(resource_name)
+
+        # Update cr
+        cr["spec"]["deadLetterConfig"]["targetARN"] = resources.EICQueueOnFailure.arn
+
+        #Patch k8s resource
+        k8s.patch_custom_resource(ref, cr)
+        time.sleep(UPDATE_WAIT_AFTER_SECONDS)
+
+        #Check function_snapstart update fields
+        function = lambda_validator.get_function(resource_name)
+        assert function["Configuration"]["DeadLetterConfig"]["TargetArn"] == resources.EICQueueOnFailure.arn
+
+        # Delete k8s resource
+        _, deleted = k8s.delete_custom_resource(ref)
+        assert deleted is True
+
+        time.sleep(DELETE_WAIT_AFTER_SECONDS)
+
+        # Check Lambda function doesn't exist
+        assert not lambda_validator.function_exists(resource_name)
+
     def test_function_event_invoke_config(self, lambda_client):
         resource_name = random_suffix_name("lambda-function", 24)