feat: add instance template public api (#7707)

Signed-off-by: Liang Deng <[email protected]>
(cherry picked from commit 6e30e0b)

pkg/controller/instanceset/instance_template_util.go

@@ -0,0 +1,46 @@
+package instanceset
+
+import (
+	corev1 "k8s.io/api/core/v1"
+
+	workloads "github.com/apecloud/kubeblocks/apis/workloads/v1alpha1"
+)
+
+// TODO: remove these after extract the Schema of the API types from Kubeblocks into a separate Go package.
+
+// InstanceSetExt serves as a Public Struct,
+// used as the type for the input parameters of BuildInstanceTemplateExts.
+type InstanceSetExt struct {
+	Its               *workloads.InstanceSet
+	InstanceTemplates []*workloads.InstanceTemplate
+}
+
+// InstanceTemplateExt serves as a Public Struct,
+// used as the type for the construction results returned by BuildInstanceTemplateExts.
+type InstanceTemplateExt struct {
+	Name     string
+	Replicas int32
+	corev1.PodTemplateSpec
+	VolumeClaimTemplates []corev1.PersistentVolumeClaim
+}
+
+// BuildInstanceTemplateExts serves as a Public API, through which users can obtain InstanceTemplateExt objects
+// processed by the buildInstanceTemplateExts function.
+// Its main purpose is to acquire the PodTemplate rendered by InstanceTemplate.
+func BuildInstanceTemplateExts(itsExt *InstanceSetExt) []*InstanceTemplateExt {
+	itsExts := buildInstanceTemplateExts(&instanceSetExt{
+		its:               itsExt.Its,
+		instanceTemplates: itsExt.InstanceTemplates,
+	})
+	var instanceTemplateExts []*InstanceTemplateExt
+	for _, itsExt := range itsExts {
+		instanceTemplateExts = append(instanceTemplateExts, (*InstanceTemplateExt)(itsExt))
+	}
+	return instanceTemplateExts
+}
+
+// BuildInstanceTemplates serves as a Public API, allowing users to construct InstanceTemplates.
+// The constructed InstanceTemplates can be used as part of the input for BuildInstanceTemplateExts.
+func BuildInstanceTemplates(totalReplicas int32, instances []workloads.InstanceTemplate, instancesCompressed *corev1.ConfigMap) []*workloads.InstanceTemplate {
+	return buildInstanceTemplates(totalReplicas, instances, instancesCompressed)
+}