Add GetRegion method to HostHandler interface (#7451)

* Add GetRegion method to HostHandler interface

* Remove exported Region field from `AWSHost` type

In package `github.com/whisthq/whist/backend/services/scaling-service/hosts/aws`. Replace with `region` field.

backend/services/scaling-service/hosts/aws/aws_host.go

@@ -27,7 +27,7 @@ import (
 // AWSHost implements the HostHandler interface using the AWS sdk.
 type AWSHost struct {
 	// The AWS region the host is initialized in.
-	Region string
+	region string
 	// The AWS specific configurations, including credentials.
 	Config aws.Config
 	// The EC2 client used for calling the AWS EC2 service API.
@@ -52,7 +52,7 @@ func (host *AWSHost) Initialize(region string) error {
 	}
 
 	// Start AWS host and EC2 client
-	host.Region = region
+	host.region = region
 	host.Config = cfg
 	host.EC2 = ec2.NewFromConfig(cfg)
 
@@ -81,6 +81,11 @@ func (host *AWSHost) Initialize(region string) error {
 	return nil
 }
 
+// GetRegion is part of the HostHandler interface.
+func (h *AWSHost) GetRegion() string {
+	return h.region
+}
+
 // MakeInstances is a simple method that calls the RunInstances function from the ec2 client.
 func (host *AWSHost) MakeInstances(c context.Context, input *ec2.RunInstancesInput) (*ec2.RunInstancesOutput, error) {
 	return host.EC2.RunInstances(c, input)
@@ -162,7 +167,7 @@ func (host *AWSHost) SpinUpInstances(scalingCtx context.Context, numInstances in
 			ImageID    = aws.ToString(outputInstance.ImageId)
 			Type       = string(outputInstance.InstanceType)
 			InstanceID = aws.ToString(outputInstance.InstanceId)
-			Region     = host.Region
+			Region     = host.region
 			Status     = "PRE_CONNECTION"
 			ClientSHA  = image.ClientSHA
 			Name       = host.GenerateName()
@@ -372,7 +377,7 @@ func (host *AWSHost) getInstanceProfile() string {
 // GenerateName is a helper function for generating an instance
 // name using a random UUID.
 func (host *AWSHost) GenerateName() string {
-	return utils.Sprintf("ec2-%v-%v-%v-%v", host.Region, metadata.GetAppEnvironmentLowercase(),
+	return utils.Sprintf("ec2-%v-%v-%v-%v", host.region, metadata.GetAppEnvironmentLowercase(),
 		metadata.GetGitCommit()[0:7], shortuuid.New())
 }
 

backend/services/scaling-service/hosts/host_handler.go

@@ -19,6 +19,10 @@ import (
 // implementation for each cloud service provider, which will interact directly with the provider's API.
 type HostHandler interface {
 	Initialize(region string) error
+
+	// GetRegion returns the name of the region with which an instance of the
+	// HostHandler type is associated.
+	GetRegion() string
 	SpinUpInstances(scalingCtx context.Context, numInstances int32, maxWaitTimeReady time.Duration, image subscriptions.Image) (createdInstances []subscriptions.Instance, err error)
 	SpinDownInstances(scalingCtx context.Context, instanceIDs []string) error
 	WaitForInstanceTermination(context.Context, time.Duration, []string) error

backend/services/scaling-service/scaling_algorithms/default/actions_test.go

@@ -195,6 +195,10 @@ func (db *mockDBClient) UpdateMandelbox(_ context.Context, _ subscriptions.Whist
 // mockHostHandler is used to test all interactions with cloud providers
 type mockHostHandler struct{}
 
+func (h *mockHostHandler) GetRegion() string {
+	return "blah"
+}
+
 func (mh *mockHostHandler) Initialize(region string) error {
 	return nil
 }