helper/keysutil: Add a LoadPolicy function (#4116)

* helper/keysutil: Add a LoadPolicy function

* Use the load policy function in the lock manager

helper/keysutil/lock_manager.go

@@ -500,23 +500,5 @@ func (lm *LockManager) DeletePolicy(ctx context.Context, storage logical.Storage
 }
 
 func (lm *LockManager) getStoredPolicy(ctx context.Context, storage logical.Storage, name string) (*Policy, error) {
-	// Check if the policy already exists
-	raw, err := storage.Get(ctx, "policy/"+name)
-	if err != nil {
-		return nil, err
-	}
-	if raw == nil {
-		return nil, nil
-	}
-
-	// Decode the policy
-	var policy Policy
-	err = jsonutil.DecodeJSON(raw.Value, &policy)
-	if err != nil {
-		return nil, err
-	}
-
-	policy.versionPrefixCache = &sync.Map{}
-
-	return &policy, nil
+	return LoadPolicy(ctx, storage, "policy/"+name)
 }

helper/keysutil/policy.go

@@ -262,6 +262,28 @@ func NewPolicy(config PolicyConfig) *Policy {
 	}
 }
 
+// LoadPolicy will load a policy from the provided storage path and set the
+// necessary un-exported variables. It is particularly useful when accessing a
+// policy without the lock manager.
+func LoadPolicy(ctx context.Context, s logical.Storage, path string) (*Policy, error) {
+	raw, err := s.Get(ctx, path)
+	if err != nil {
+		return nil, err
+	}
+	if raw == nil {
+		return nil, nil
+	}
+
+	var policy Policy
+	err = jsonutil.DecodeJSON(raw.Value, &policy)
+	if err != nil {
+		return nil, err
+	}
+
+	policy.versionPrefixCache = &sync.Map{}
+	return &policy, nil
+}
+
 // Policy is the struct used to store metadata
 type Policy struct {
 	Name string      `json:"name"`