Put AMI ID retrieval under its own function

pkg/cloud/aws/actuators/machine/actuator.go

@@ -271,43 +271,16 @@ func getSubnetIDs(subnet providerconfigv1.AWSResourceReference, availabilityZone
 	return subnetIDs, nil
 }
 
-// CreateMachine starts a new AWS instance as described by the cluster and machine resources
-func (a *Actuator) CreateMachine(cluster *clusterv1.Cluster, machine *clusterv1.Machine) (*ec2.Instance, error) {
-	machineProviderConfig, err := ProviderConfigFromMachine(machine)
-	if err != nil {
-		glog.Errorf("error decoding MachineProviderConfig: %v", err)
-		return nil, err
-	}
-
-	credentialsSecretName := ""
-	if machineProviderConfig.CredentialsSecret != nil {
-		credentialsSecretName = machineProviderConfig.CredentialsSecret.Name
-	}
-	client, err := a.awsClientBuilder(a.kubeClient, credentialsSecretName, machine.Namespace, machineProviderConfig.Placement.Region)
-	if err != nil {
-		glog.Errorf("unable to obtain AWS client: %v", err)
-		return nil, fmt.Errorf("unable to obtain AWS client: %v", err)
-	}
-
-	// We explicitly do NOT want to remove stopped masters.
-	if !IsMaster(machine) {
-		// Prevent having a lot of stopped nodes sitting around.
-		err = a.removeStoppedMachine(machine, client)
-		if err != nil {
-			glog.Errorf("unable to remove stopped machines: %v", err)
-			return nil, fmt.Errorf("unable to remove stopped nodes: %v", err)
-		}
-	}
-
-	// Get AMI to use
-	var amiID *string
-	if machineProviderConfig.AMI.ID != nil {
-		amiID = machineProviderConfig.AMI.ID
+func getAMI(AMI providerconfigv1.AWSResourceReference, client awsclient.Client) (*string, error) {
+	if AMI.ID != nil {
+		amiID := AMI.ID
 		glog.Infof("Using AMI %s", *amiID)
-	} else if len(machineProviderConfig.AMI.Filters) > 0 {
+		return amiID, nil
+	}
+	if len(AMI.Filters) > 0 {
 		glog.Info("Describing AMI based on filters")
 		describeImagesRequest := ec2.DescribeImagesInput{
-			Filters: buildEC2Filters(machineProviderConfig.AMI.Filters),
+			Filters: buildEC2Filters(AMI.Filters),
 		}
 		describeAMIResult, err := client.DescribeImages(&describeImagesRequest)
 		if err != nil {
@@ -335,9 +308,42 @@ func (a *Actuator) CreateMachine(cluster *clusterv1.Cluster, machine *clusterv1.
 				latestTime = imageTime
 			}
 		}
-		amiID = latestImage.ImageId
-	} else {
-		return nil, fmt.Errorf("AMI ID or AMI filters need to be specified")
+		return latestImage.ImageId, nil
+	}
+	return nil, fmt.Errorf("AMI ID or AMI filters need to be specified")
+}
+
+// CreateMachine starts a new AWS instance as described by the cluster and machine resources
+func (a *Actuator) CreateMachine(cluster *clusterv1.Cluster, machine *clusterv1.Machine) (*ec2.Instance, error) {
+	machineProviderConfig, err := ProviderConfigFromMachine(machine)
+	if err != nil {
+		glog.Errorf("error decoding MachineProviderConfig: %v", err)
+		return nil, err
+	}
+
+	credentialsSecretName := ""
+	if machineProviderConfig.CredentialsSecret != nil {
+		credentialsSecretName = machineProviderConfig.CredentialsSecret.Name
+	}
+	client, err := a.awsClientBuilder(a.kubeClient, credentialsSecretName, machine.Namespace, machineProviderConfig.Placement.Region)
+	if err != nil {
+		glog.Errorf("unable to obtain AWS client: %v", err)
+		return nil, fmt.Errorf("unable to obtain AWS client: %v", err)
+	}
+
+	// We explicitly do NOT want to remove stopped masters.
+	if !IsMaster(machine) {
+		// Prevent having a lot of stopped nodes sitting around.
+		err = a.removeStoppedMachine(machine, client)
+		if err != nil {
+			glog.Errorf("unable to remove stopped machines: %v", err)
+			return nil, fmt.Errorf("unable to remove stopped nodes: %v", err)
+		}
+	}
+
+	amiID, err := getAMI(machineProviderConfig.AMI, client)
+	if err != nil {
+		return nil, fmt.Errorf("error getting AMI: %v,", err)
 	}
 
 	securityGroupsIDs, err := getSecurityGroupsIDs(machineProviderConfig.SecurityGroups, client)