cluster-autoscaler: support Brightbox image pattern

cluster-autoscaler/cloudprovider/brightbox

Allow scaled workers to be built from an image name pattern as well as
an image id. This deals with long running clusters where the official
image is updated with security changes over time.

cluster-autoscaler/cloudprovider/brightbox/brightbox_node_group.go

@@ -359,24 +359,32 @@ func makeNodeGroupFromAPIDetails(
 	if mapData["server_group"] == "" {
 		return nil, cloudprovider.ErrIllegalConfiguration
 	}
+	ng := brightboxNodeGroup{
+		id:      mapData["server_group"],
+		minSize: minSize,
+		maxSize: maxSize,
+		Cloud:   cloudclient,
+	}
+	imageID := mapData["image"]
+	if !(len(imageID) == 9 && strings.HasPrefix(imageID, "img-")) {
+		image, err := ng.GetImageByName(imageID)
+		if err != nil || image == nil {
+			return nil, cloudprovider.ErrIllegalConfiguration
+		}
+		imageID = image.Id
+	}
 	userData := mapData["user_data"]
 	options := &brightbox.ServerOptions{
-		Image:        mapData["image"],
+		Image:        imageID,
 		Name:         &name,
 		ServerType:   mapData["type"],
 		Zone:         mapData["zone"],
 		UserData:     &userData,
 		ServerGroups: mergeServerGroups(mapData),
 	}
-	result := brightboxNodeGroup{
-		id:            mapData["server_group"],
-		minSize:       minSize,
-		maxSize:       maxSize,
-		serverOptions: options,
-		Cloud:         cloudclient,
-	}
-	klog.V(4).Info(result.Debug())
-	return &result, nil
+	ng.serverOptions = options
+	klog.V(4).Info(ng.Debug())
+	return &ng, nil
 }
 
 func mergeServerGroups(data map[string]string) []string {
@@ -459,3 +467,14 @@ func (ng *brightboxNodeGroup) isMissing(serverID string) (bool, error) {
 	}
 	return true, nil
 }
+
+// filter returns a new slice with all elements from the from the
+// input elements for which the provided predicate function returns true.
+func filter[T any](input []T, pred func(T) bool) (output []T) {
+	for _, v := range input {
+		if pred(v) {
+			output = append(output, v)
+		}
+	}
+	return output
+}

cluster-autoscaler/cloudprovider/brightbox/k8ssdk/brightbox_interface.go

@@ -18,6 +18,8 @@ import (
 	"context"
 	"fmt"
 	"net/http"
+	"regexp"
+	"sort"
 	"strings"
 
 	brightbox "k8s.io/autoscaler/cluster-autoscaler/cloudprovider/brightbox/gobrightbox"
@@ -166,6 +168,36 @@ func (c *Cloud) GetServerType(identifier string) (*brightbox.ServerType, error)
 	return client.ServerType(identifier)
 }
 
+// GetImageByName obtains the most recent available image that matches the supplied pattern
+func (c *Cloud) GetImageByName(name string) (*brightbox.Image, error) {
+	klog.V(4).Infof("GetImageByName %q", name)
+	client, err := c.CloudClient()
+	if err != nil {
+		return nil, err
+	}
+	klog.V(6).Info("GetImageByName compiling regexp")
+	nameRe, err := regexp.Compile(name)
+	if err != nil {
+		return nil, err
+	}
+	klog.V(6).Info("GetImageByName retrieving images")
+	images, err := client.Images()
+	if err != nil {
+		return nil, err
+	}
+	klog.V(6).Info("GetImageByName filtering images")
+	filteredImages := filter(
+		images,
+		func(i brightbox.Image) bool {
+			return i.Official &&
+				i.Status == status.Available &&
+				nameRe.MatchString(i.Name)
+		},
+	)
+	klog.V(6).Infof("GetImageByName images selected (%+v)", filteredImages)
+	return mostRecent(filteredImages), nil
+}
+
 // GetConfigMaps obtains the list of Config Maps on the account
 func (c *Cloud) GetConfigMaps() ([]brightbox.ConfigMap, error) {
 	klog.V(4).Info("GetConfigMaps")
@@ -555,3 +587,27 @@ func ErrorIfAcmeNotComplete(acme *brightbox.LoadBalancerAcme) error {
 	}
 	return nil
 }
+
+// Returns the most recent item out of a slice of items with Dates
+// or nil if there are no items
+func mostRecent(items []brightbox.Image) *brightbox.Image {
+	if len(items) == 0 {
+		return nil
+	}
+	sortedItems := items
+	sort.Slice(items, func(i, j int) bool {
+		return items[i].CreatedAt.Unix() > items[j].CreatedAt.Unix()
+	})
+	return &sortedItems[0]
+}
+
+// filter returns a new slice with all elements from the
+// input elements for which the provided predicate function returns true.
+func filter[T any](input []T, pred func(T) bool) (output []T) {
+	for _, v := range input {
+		if pred(v) {
+			output = append(output, v)
+		}
+	}
+	return output
+}

cluster-autoscaler/cloudprovider/brightbox/k8ssdk/cloud_access.go

@@ -92,6 +92,9 @@ type CloudAccess interface {
 	// DestroyCloudIP issues a request to destroy the cloud ip
 	DestroyCloudIP(identifier string) error
 
+	// ConfigMaps retrieves a list of all config maps
+	Images() ([]brightbox.Image, error)
+
 	// ConfigMaps retrieves a list of all config maps
 	ConfigMaps() ([]brightbox.ConfigMap, error)