fix: don't spam nodes with updates and instead pull the registry on keepalive

TODO.md

@@ -1,3 +1,56 @@
+# Background
+Some background first:
+the node can have multiple roles
+this includes (but not limited to)
+* Host (can generate events)
+* DNS (can consume the events and act on them)
+* Something else that I might come up with (the architecture has to be expandable)
+
+# Control pane (3+ nodes)
+* Quorum
+    * Consists of $n / 2 + 1$ nodes
+    * Cluster is considered "degraded" if no quorum can be created
+* Stores an event log
+    * **Only** leader can append to the log (with quorum permission)
+* Membership authority
+    * No joins without quorum approval
+    * Leaves are not propagated without quorum
+* Manages epoch (useful for GC)
+    * Node $N$ with $N.epoch != cluster.epoch$ can **not** join the cluster, and has to re-join (bootstrap)
+* Can (but doesn't have to) be a bootstrap point
+
+# Membership
+* Membership is managed though SWIM
+* Each node contains a small slice of the entire network
+## Joining
+Each node has an array of roles:
+1. That it performs
+2. That it requires to operate (can be moved out to the master, or the shared type)
+3. That it needs for bootstrapping (analogous to 2.)
+
+Node can join via a master or via other nodes
+When a node requests to join, the responder makes a request to the CP and asks for a permission to add this node
+* If master allows
+    1. The node gets a membership digest from the CP.
+    2. The node *can* be brought up to speed using it's neighbors from 1.
+    3. Node join event gets broadcasted over SWIM gossiping
+* Otherwise, nothing happens
+
+# Host node
+## Bootstrap
+Host node requests `dns` nodes on join (and other node types, such as `ns`, `nginx`, etc... They should really be called something like `dns_processor`, and the internals (how it processes the dns) should not be visible to the cluster, but that's a task for a future me)
+When a new update occurs, it sends the update to *some* `dns` hosts.
+
+# DNS node
+## Bootstrap
+First, it gets all the available `hosts` from the CP
+Then it requests their configs and sets map[hostName]seq accordingly
+## Simple join (when other nodes exist)
+It requests it's config from other nodes and that's it
+
+<!-- TODO: finish the TODO file lol -->
+
+# Minor To-Do
 - auth middleware lol
 - move request logging out of the request handling into a middleware
 - nginx role