+/*
+ * netdata registry
+ *
+ * this header file describes the public interface
+ * to the netdata registry
+ *
+ * only these high level functions are exposed
+ *
+ */
+
+// ----------------------------------------------------------------------------
+// TODO
+//
+// 1. the default tracking cookie expires in 1 year, but the persons are not
+// removed from the db - this means the database only grows - ideally the
+// database should be cleaned in registry_db_save() for both on-disk and
+// on-memory entries.
+//
+// Cleanup:
+// i. Find all the PERSONs that have expired cookie
+// ii. For each of their PERSON_URLs:
+// - decrement the linked MACHINE links
+// - if the linked MACHINE has no other links, remove the linked MACHINE too
+// - remove the PERSON_URL
+//
+// 2. add protection to prevent abusing the registry by flooding it with
+// requests to fill the memory and crash it.
+//
+// Possible protections:
+// - limit the number of URLs per person
+// - limit the number of URLs per machine
+// - limit the number of persons
+// - limit the number of machines
+// - [DONE] limit the size of URLs
+// - [DONE] limit the size of PERSON_URL names
+// - limit the number of requests that add data to the registry,
+// per client IP per hour
+//
+// 3. lower memory requirements
+//
+// - embed avl structures directly into registry objects, instead of DICTIONARY
+// [DONE for PERSON_URLs, PENDING for MACHINE_URLs]
+// - store GUIDs in memory as UUID instead of char *
+// - do not track persons using the demo machines only
+// (i.e. start tracking them only when they access a non-demo machine)
+// - [DONE] do not track custom dashboards by default
+
+