Add unregistration as future enhancement

Author: brunorijsman

.vscode/settings.json

@@ -58,6 +58,7 @@
         "Shamir",
         "Shor's",
         "Starlette",
+        "unregistration",
         "urandom",
         "Uvicorn",
         "venv"

TODO

@@ -20,11 +20,6 @@ TODO: Make sure key has unique key UUID
 
 TODO: Key initiator: Select N peer hub (initially: all peer hubs)
 
-TODO: Have client unregister itself from all hubs when it shuts down.
-      The API call should use the DELETE method.
-      Shutting down should not cause the client to unregister itself; make unregistration
-      an explicit option.
-
 TODO: Allow a client to register itself again (after a restart). Done; just need to test.
 
 TODO: Add statistics management API and topology command to query it.

client/__main__.py

@@ -47,7 +47,7 @@ async def lifespan(_app: fastapi.FastAPI):
     """
     _CLIENT.start_all_peer_hubs()
     yield
-    # TODO: Unregister (attempt without retry or very limited)
+    # We currently do not have any shutdown actions.
 
 
 _APP = fastapi.FastAPI(lifespan=lifespan)

client/client.py

@@ -124,13 +124,6 @@ def start_all_peer_hubs(self) -> None:
         for peer_hub in self._peer_hubs:
             peer_hub.start_register_task()
 
-    async def unregister_from_all_peer_hubs(self) -> None:
-        """
-        Unregister from all peer hubs.
-        """
-        for peer_hub in self._peer_hubs:
-            await peer_hub.unregister()
-
     async def scatter_key_amongst_peer_hubs(self, key: UserKey) -> None:
         """
         Split the key into key shares, and send each key share to a peer hub.

client/peer_hub.py

@@ -148,12 +148,6 @@ async def attempt_registration(self) -> bool:
         self._registered = True
         return True
 
-    async def unregister(self) -> None:
-        """
-        Unregister this client from the peer hub.
-        """
-        # TODO: Implement this and call it from somewhere
-
     def start_request_psrd_task_if_needed(self) -> None:
         """
         Start request PSRD task(s) if needed.

docs/protocol-guide.md

@@ -1054,4 +1054,11 @@ been made including:
 
  * The `POST` method for the `Get key with key IDs` interface is not supported.
 
- * Error handling is not as robust as it should be.
+ * Error handling is not as robust as it should be.
+
+ ### Unregistration
+
+ When a client starts, it registers itself with all hubs, using the PUT registration API.
+ Currently, client never unregister.
+ We can add an unregistration mechanism by adding a DELETE registration API and calling it
+ when a client shuts down orderly.

manager.py

@@ -196,7 +196,7 @@ def stop_topology(self):
         """
         Stop all nodes.
         """
-        # Stop the clients first, so that they can cleanly unregister from the hubs.
+        # Stop the clients first, in case we implement unregistration at some point
         for node in self.selected_nodes(reverse_order=True):
             self.stop_node(node)
         self.wait_for_selected_nodes_stopped()