Bug fix for ProvisionedConcurrency (#106)

Issue #, if available:
Related PR: #97 

**Summary**
Fixing deletion part for `ProvisionedConcurrency` field.

**Description:**
This PR is related to bug fixes in [previous PR](#97) related to `ProvisionedConcurrency` implementation. When the user deleted the set configurations for Alias resource, the configurations were not deleted from the Console side, instead it used to throw an error. Fixed the bug by introducing a new condition to check if the desired configurations are nil or not, if yes then call the delete API. 

Example of changes for `ProvisionedConcurrency` in Alias resource is given below:

```
if desired.ko.Spec.ProvisionedConcurrencyConfig == nil {
	input_delete := &svcsdk.DeleteProvisionedConcurrencyConfigInput{
		FunctionName: aws.String(*desired.ko.Spec.FunctionName),
		Qualifier:    aws.String(*desired.ko.Spec.Name),
	}
	_, err = rm.sdkapi.DeleteProvisionedConcurrencyConfigWithContext(ctx, input_delete)
	rm.metrics.RecordAPICall("DELETE", "DeleteProvisionedConcurrency", err)
	if err != nil {
		return err
	}
	return nil
}
```

This PR contains implementation code and E2E test to validate the changes. 

**Acknowledgment**
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: "2023-07-24T18:19:28Z"
+  build_date: "2023-08-02T20:25:36Z"
   build_hash: e9b68590da73ce9143ba1e4361cebdc1d876c81e
   go_version: go1.19
   version: v0.26.1-7-ge9b6859

pkg/resource/alias/hooks.go

@@ -71,6 +71,8 @@ func (rm *resourceManager) syncEventInvokeConfig(
 	return r, nil
 }
 
+// updateProvisionedConcurrency calls `PutProvisionedConcurrencyConfig` to update the fields
+// or `DeleteProvisionedConcurrencyConfig` if users removes the fields
 func (rm *resourceManager) updateProvisionedConcurrency(
 	ctx context.Context,
 	desired *resource,
@@ -80,20 +82,26 @@ func (rm *resourceManager) updateProvisionedConcurrency(
 	exit := rlog.Trace("rm.updateProvisionedConcurrency")
 	defer exit(err)
 
-	dspec := desired.ko.Spec
-	input := &svcsdk.PutProvisionedConcurrencyConfigInput{
-		FunctionName: aws.String(*dspec.FunctionName),
-		Qualifier:    aws.String(*dspec.Name),
+	// Check if the user deleted the 'ProvisionedConcurrency' configuration
+	// If yes, delete ProvisionedConcurrencyConfig
+	if desired.ko.Spec.ProvisionedConcurrencyConfig == nil || desired.ko.Spec.ProvisionedConcurrencyConfig.ProvisionedConcurrentExecutions == nil {
+		input_delete := &svcsdk.DeleteProvisionedConcurrencyConfigInput{
+			FunctionName: aws.String(*desired.ko.Spec.FunctionName),
+			Qualifier:    aws.String(*desired.ko.Spec.Name),
+		}
+		_, err = rm.sdkapi.DeleteProvisionedConcurrencyConfigWithContext(ctx, input_delete)
+		rm.metrics.RecordAPICall("DELETE", "DeleteProvisionedConcurrency", err)
+		if err != nil {
+			return err
+		}
+		return nil
 	}
 
-	if desired.ko.Spec.ProvisionedConcurrencyConfig != nil {
-		if desired.ko.Spec.ProvisionedConcurrencyConfig.ProvisionedConcurrentExecutions != nil {
-			input.ProvisionedConcurrentExecutions = aws.Int64(*desired.ko.Spec.ProvisionedConcurrencyConfig.ProvisionedConcurrentExecutions)
-		} else {
-			input.ProvisionedConcurrentExecutions = aws.Int64(0)
-		}
-	} else {
-		input.ProvisionedConcurrentExecutions = aws.Int64(0)
+	dspec := desired.ko.Spec
+	input := &svcsdk.PutProvisionedConcurrencyConfigInput{
+		FunctionName:                    aws.String(*dspec.FunctionName),
+		Qualifier:                       aws.String(*dspec.Name),
+		ProvisionedConcurrentExecutions: aws.Int64(*dspec.ProvisionedConcurrencyConfig.ProvisionedConcurrentExecutions),
 	}
 
 	_, err = rm.sdkapi.PutProvisionedConcurrencyConfigWithContext(ctx, input)
@@ -104,10 +112,15 @@ func (rm *resourceManager) updateProvisionedConcurrency(
 	return nil
 }
 
-func (rm *resourceManager) getProvisionedConcurrencyConfig(
+// setProvisionedConcurrencyConfig sets the Provisioned Concurrency
+// for the Function's Alias
+func (rm *resourceManager) setProvisionedConcurrencyConfig(
 	ctx context.Context,
 	ko *svcapitypes.Alias,
 ) (err error) {
+	rlog := ackrtlog.FromContext(ctx)
+	exit := rlog.Trace("rm.setProvisionedConcurrencyConfig")
+	defer exit(err)
 
 	var getProvisionedConcurrencyConfigOutput *svcsdk.GetProvisionedConcurrencyConfigOutput
 	getProvisionedConcurrencyConfigOutput, err = rm.sdkapi.GetProvisionedConcurrencyConfigWithContext(
@@ -126,12 +139,17 @@ func (rm *resourceManager) getProvisionedConcurrencyConfig(
 			return err
 		}
 	} else {
-		ko.Spec.ProvisionedConcurrencyConfig.ProvisionedConcurrentExecutions = getProvisionedConcurrencyConfigOutput.RequestedProvisionedConcurrentExecutions
+		// creating ProvisionedConcurrency object to store the values returned from `Get` call
+		cloudProvisionedConcurrency := &svcapitypes.PutProvisionedConcurrencyConfigInput{}
+		cloudProvisionedConcurrency.ProvisionedConcurrentExecutions = getProvisionedConcurrencyConfigOutput.RequestedProvisionedConcurrentExecutions
+		ko.Spec.ProvisionedConcurrencyConfig = cloudProvisionedConcurrency
 	}
 
 	return nil
 }
 
+// getFunctionEventInvokeConfig will describe the fields that are
+// custom to the Alias resource
 func (rm *resourceManager) getFunctionEventInvokeConfig(
 	ctx context.Context,
 	ko *svcapitypes.Alias,
@@ -183,6 +201,8 @@ func (rm *resourceManager) getFunctionEventInvokeConfig(
 	return nil
 }
 
+// setResourceAdditionalFields will describe the fields that are not return by the
+// getFunctionConfiguration API call
 func (rm *resourceManager) setResourceAdditionalFields(
 	ctx context.Context,
 	ko *svcapitypes.Alias,
@@ -191,14 +211,16 @@ func (rm *resourceManager) setResourceAdditionalFields(
 	exit := rlog.Trace("rm.setResourceAdditionalFields")
 	defer exit(err)
 
+	// To set Asynchronous Invocations for the function's alias
 	eic_err := rm.getFunctionEventInvokeConfig(ctx, ko)
 	if eic_err != nil {
 		return eic_err
 	}
 
-	pc_err := rm.getProvisionedConcurrencyConfig(ctx, ko)
-	if pc_err != nil {
-		return pc_err
+	// To set Provisioned Concurrency for the function's alias
+	err = rm.setProvisionedConcurrencyConfig(ctx, ko)
+	if err != nil {
+		return err
 	}
 
 	return nil

test/e2e/tests/test_alias.py

@@ -245,17 +245,28 @@ def test_provisioned_concurrency_config(self, lambda_client, lambda_function):
          # Check alias exists
         assert lambda_validator.alias_exists(resource_name, lambda_function_name)
 
-        # Update cr
+        # Update provisioned_concurrency
         cr["spec"]["provisionedConcurrencyConfig"]["provisionedConcurrentExecutions"] = 2
 
         # Patch k8s resource
         k8s.patch_custom_resource(ref, cr)
         time.sleep(UPDATE_WAIT_AFTER_SECONDS)
 
-        #Check function_event_invoke_config update fields
+        #Check provisioned_concurrency_config update fields
         provisioned_concurrency_config = lambda_validator.get_provisioned_concurrency_config(lambda_function_name,resource_name)
         assert provisioned_concurrency_config["RequestedProvisionedConcurrentExecutions"] == 2
 
+        # Delete provisioned_concurrency from alias
+        cr = k8s.wait_resource_consumed_by_controller(ref)
+        cr["spec"]["provisionedConcurrencyConfig"] = None
+
+        # Patch k8s resource     
+        k8s.patch_custom_resource(ref, cr)
+        time.sleep(UPDATE_WAIT_AFTER_SECONDS)
+
+        #Check provisioned_concurrency_config is deleted
+        assert not lambda_validator.get_provisioned_concurrency_config(lambda_function_name, resource_name)
+
         # Delete k8s resource
         _, deleted = k8s.delete_custom_resource(ref)
         assert deleted