[node operator] Add GCP client

Signed-off-by: Malte Poll <mp@edgeless.systems>

operators/constellation-node-operator/internal/gcp/client/disks.go

@@ -0,0 +1,36 @@
+package client
+
+import (
+	"fmt"
+	"regexp"
+
+	"google.golang.org/genproto/googleapis/cloud/compute/v1"
+)
+
+var (
+	diskSourceRegex = regexp.MustCompile(`^https://www.googleapis.com/compute/v1/projects/([^/]+)/zones/([^/]+)/disks/([^/]+)$`)
+	computeAPIBase  = regexp.MustCompile(`^https://www.googleapis.com/compute/v1/(.+)$`)
+)
+
+// diskSourceToDiskReq converts a disk source URI to a disk request.
+func diskSourceToDiskReq(diskSource string) (*compute.GetDiskRequest, error) {
+	matches := diskSourceRegex.FindStringSubmatch(diskSource)
+	if len(matches) != 4 {
+		return nil, fmt.Errorf("error splitting diskSource: %v", diskSource)
+	}
+	return &compute.GetDiskRequest{
+		Disk:    matches[3],
+		Project: matches[1],
+		Zone:    matches[2],
+	}, nil
+}
+
+// uriNormalize normalizes a compute API URI by removing the optional URI prefix.
+// for normalization, the prefix 'https://www.googleapis.com/compute/v1/' is removed.
+func uriNormalize(imageURI string) string {
+	matches := computeAPIBase.FindStringSubmatch(imageURI)
+	if len(matches) != 2 {
+		return imageURI
+	}
+	return matches[1]
+}