first functional test

internal/operations/parsers.go

@@ -0,0 +1,26 @@
+package operations
+
+import (
+	"encoding/json"
+
+	dep "k8s.io/api/apps/v1"
+	pod "k8s.io/api/core/v1"
+)
+
+func parseDeployment(object []byte) (*dep.Deployment, error) {
+	var dp dep.Deployment
+	if err := json.Unmarshal(object, &dp); err != nil {
+		return nil, err
+	}
+
+	return &dp, nil
+}
+
+func parsePod(object []byte) (*pod.Pod, error) {
+	var pod pod.Pod
+	if err := json.Unmarshal(object, &pod); err != nil {
+		return nil, err
+	}
+
+	return &pod, nil
+}

internal/operations/podsValidation.go

@@ -1,5 +1,30 @@
 package operations
 
+import (
+	"strings"
+
+	admission "k8s.io/api/admission/v1"
+)
+
 func PodsValidation() Hook {
-	return Hook{}
+	return Hook{
+		Create: podValidationCreate(),
+	}
+}
+
+func podValidationCreate() AdmitFunc {
+	return func(r *admission.AdmissionRequest) (*Result, error) {
+		pod, err := parsePod(r.Object.Raw)
+		if err != nil {
+			return &Result{Msg: err.Error()}, nil
+		}
+
+		for _, c := range pod.Spec.Containers {
+			if strings.HasSuffix(c.Image, ":latest") {
+				return &Result{Msg: "You cannot use the tag 'latest' in a container."}, nil
+			}
+		}
+
+		return &Result{Allowed: true}, nil
+	}
 }