prep for actual admission/hook efforts

internal/operations/hook.go

@@ -0,0 +1,51 @@
+package operations
+
+//https://github.com/douglasmakey/admissioncontroller
+
+import (
+	"fmt"
+
+	admission "k8s.io/api/admission/v1"
+)
+
+// Result contains the result of an admission request
+type Result struct {
+	Allowed  bool
+	Msg      string
+	PatchOps []PatchOperation
+}
+
+// AdmitFunc defines how to process an admission request
+type AdmitFunc func(request *admission.AdmissionRequest) (*Result, error)
+
+// Hook represents the set of functions for each operation in an admission webhook.
+type Hook struct {
+	Create  AdmitFunc
+	Delete  AdmitFunc
+	Update  AdmitFunc
+	Connect AdmitFunc
+}
+
+// Execute evaluates the request and try to execute the function for operation specified in the request.
+func (h *Hook) Execute(r *admission.AdmissionRequest) (*Result, error) {
+	switch r.Operation {
+	case admission.Create:
+		return wrapperExecution(h.Create, r)
+	case admission.Update:
+		return wrapperExecution(h.Update, r)
+	case admission.Delete:
+		return wrapperExecution(h.Delete, r)
+	case admission.Connect:
+		return wrapperExecution(h.Connect, r)
+	}
+
+	return &Result{Msg: fmt.Sprintf("Invalid operation: %s", r.Operation)}, nil
+}
+
+func wrapperExecution(fn AdmitFunc, r *admission.AdmissionRequest) (*Result, error) {
+	if fn == nil {
+		return nil, fmt.Errorf("operation %s is not registered", r.Operation)
+	}
+
+	return fn(r)
+}