daemon: update to nftables update tracker to use a queue for more reactive changes

daemon/core/nodes/network.py

@@ -6,8 +6,10 @@ import logging
 import math
 import threading
 import time
+from collections import OrderedDict
 from pathlib import Path
-from typing import TYPE_CHECKING, Dict, List, Optional, Set, Type
+from queue import Queue
+from typing import TYPE_CHECKING, Dict, List, Optional, Type
 
 import netaddr
 
@@ -38,6 +40,22 @@ if TYPE_CHECKING:
 LEARNING_DISABLED: int = 0
 
 
+class SetQueue(Queue):
+    """
+    Set backed queue to avoid duplicate submissions.
+    """
+
+    def _init(self, maxsize):
+        self.queue: OrderedDict = OrderedDict()
+
+    def _put(self, item):
+        self.queue[item] = None
+
+    def _get(self):
+        key, _ = self.queue.popitem(last=False)
+        return key
+
+
 class NftablesQueue:
     """
     Helper class for queuing up nftables commands into rate-limited
@@ -62,7 +80,7 @@ class NftablesQueue:
         # list of pending nftables commands
         self.cmds: List[str] = []
         # list of WLANs requiring update
-        self.updates: Set["CoreNetwork"] = set()
+        self.updates: SetQueue = SetQueue()
         # timestamps of last WLAN update; this keeps track of WLANs that are
         # using this queue
         self.last_update_time: Dict["CoreNetwork", float] = {}
@@ -93,6 +111,7 @@ class NftablesQueue:
                 return
             self.running = False
             if self.run_thread:
+                self.updates.put(None)
                 self.run_thread.join()
                 self.run_thread = None
 
@@ -115,20 +134,16 @@ class NftablesQueue:
         :return: nothing
         """
         while self.running:
-            with self.lock:
-                discard = set()
-                for net in self.updates:
-                    if not net.up:
-                        self.last_update_time[net] = time.monotonic()
-                        discard.add(net)
-                        continue
-                    if self.last_update(net) > self.rate:
-                        self.build_cmds(net)
-                        self.commit(net)
-                        self.last_update_time[net] = time.monotonic()
-                        discard.add(net)
-                self.updates -= discard
-            time.sleep(self.rate)
+            net = self.updates.get()
+            if net is None:
+                break
+            if not net.up:
+                self.last_update_time[net] = time.monotonic()
+            elif self.last_update(net) > self.rate:
+                with self.lock:
+                    self.build_cmds(net)
+                    self.commit(net)
+                self.last_update_time[net] = time.monotonic()
 
     def commit(self, net: "CoreNetwork") -> None:
         """
@@ -153,15 +168,13 @@ class NftablesQueue:
         :param net: wlan network
         :return: nothing
         """
-        with self.lock:
-            self.updates.add(net)
+        self.updates.put(net)
 
     def delete_table(self, net: "CoreNetwork") -> None:
         """
         Delete nftable bridge rule table.
 
         :param net: network to delete table for
-        :param name: name of bridge table to delete
         :return: nothing
         """
         with self.lock: