[#64] engine: Add user and group targets

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

pkg/engine/interface.go

@@ -37,6 +37,8 @@ type TargetType rune
 const (
 	Namespace TargetType = 'n'
 	Container TargetType = 'c'
+	User      TargetType = 'u'
+	Group     TargetType = 'g'
 )
 
 type Target struct {
@@ -48,6 +50,8 @@ type Target struct {
 type RequestTarget struct {
 	Namespace *Target
 	Container *Target
+	User      *Target
+	Groups    []Target
 }
 
 func NewRequestTargetWithNamespace(namespace string) RequestTarget {
@@ -73,6 +77,24 @@ func NewRequestTarget(namespace, container string) RequestTarget {
 	}
 }
 
+func NewRequestTargetExtended(namespace, container, user string, groups []string) RequestTarget {
+	nt := NamespaceTarget(namespace)
+	ct := ContainerTarget(container)
+	u := UserTarget(user)
+	rt := RequestTarget{
+		Namespace: &nt,
+		Container: &ct,
+		User:      &u,
+	}
+	if len(groups) != 0 {
+		rt.Groups = make([]Target, len(groups))
+		for i := range groups {
+			rt.Groups[i] = GroupTarget(groups[i])
+		}
+	}
+	return rt
+}
+
 func (rt *RequestTarget) Targets() (targets []Target) {
 	if rt.Namespace != nil {
 		targets = append(targets, *rt.Namespace)
@@ -80,6 +102,12 @@ func (rt *RequestTarget) Targets() (targets []Target) {
 	if rt.Container != nil {
 		targets = append(targets, *rt.Container)
 	}
+	if rt.User != nil {
+		targets = append(targets, *rt.User)
+	}
+	if len(rt.Groups) != 0 {
+		targets = append(targets, rt.Groups...)
+	}
 	return
 }
 
@@ -97,6 +125,20 @@ func ContainerTarget(container string) Target {
 	}
 }
 
+func UserTarget(user string) Target {
+	return Target{
+		Type: User,
+		Name: user,
+	}
+}
+
+func GroupTarget(group string) Target {
+	return Target{
+		Type: Group,
+		Name: group,
+	}
+}
+
 // MorphRuleChainStorageReader is the interface that provides read-only methods to receive
 // data like chains, target or admin from a chain storage.
 type MorphRuleChainStorageReader interface {