[#25] engine: Refactor ChainRouter interface

* Pass RequestTarget instead only namespace
* Refactor unit-tests and dependencies

Signed-off-by: Airat Arifullin <aarifullin@yadro.com>

pkg/engine/interface.go

@@ -8,7 +8,7 @@ import (
 type ChainRouter interface {
 	// IsAllowed returns status for the operation after all checks.
 	// The second return value signifies whether a matching rule was found.
-	IsAllowed(name chain.Name, target string, r resource.Request) (status chain.Status, found bool, err error)
+	IsAllowed(name chain.Name, reqTarget RequestTarget, r resource.Request) (status chain.Status, found bool, err error)
 }
 
 // LocalOverrideStorage is the interface to manage local overrides defined
@@ -37,6 +37,45 @@ type Target struct {
 	Name string
 }
 
+// RequestTarget combines several targets on which the request is performed.
+type RequestTarget struct {
+	Namespace *Target
+	Container *Target
+}
+
+func NewRequestTargetWithNamespace(namespace string) RequestTarget {
+	nt := NamespaceTarget(namespace)
+	return RequestTarget{
+		Namespace: &nt,
+	}
+}
+
+func NewRequestTargetWithContainer(container string) RequestTarget {
+	ct := ContainerTarget(container)
+	return RequestTarget{
+		Container: &ct,
+	}
+}
+
+func NewRequestTarget(namespace, container string) RequestTarget {
+	nt := NamespaceTarget(namespace)
+	ct := ContainerTarget(container)
+	return RequestTarget{
+		Namespace: &nt,
+		Container: &ct,
+	}
+}
+
+func (rt *RequestTarget) Targets() (targets []Target) {
+	if rt.Container != nil {
+		targets = append(targets, *rt.Container)
+	}
+	if rt.Namespace != nil {
+		targets = append(targets, *rt.Namespace)
+	}
+	return
+}
+
 func NamespaceTarget(namespace string) Target {
 	return Target{
 		Type: Namespace,