chore: Refactor of FilterV2 subscription management with Time-to-live maintenance (#2341)

* Refactor of FilterV2 subscription handling and maintenance with addition subscription time-to-live support.
Fixed all tests and reworked where subscription handling changes needed it.
Adapted REST API /admin filter subscription retrieve to new filter subscription structure.

* Fix tests and PR comments

* Added filter v2 subscription timeout tests and fixed

* Fix review comments and suggestions. No functional change.

* Remove leftover echoes from test_rest_admin

* Fix failed legacy filter tests due to separation of mounting the filters.

* Small fixes, fix naming typo, removed duplicated checks in test

apps/chat2/chat2.nim

@@ -468,6 +468,7 @@ proc processInput(rfd: AsyncFD, rng: ref HmacDrbgContext) {.async.} =
     let peerInfo = parsePeerInfo(conf.filternode)
     if peerInfo.isOk():
       await node.mountFilter()
+      await node.mountLegacyFilter()
       await node.mountFilterClient()
       node.peerManager.addServicePeer(peerInfo.value, WakuLegacyFilterCodec)
 
@@ -507,7 +508,7 @@ proc processInput(rfd: AsyncFD, rng: ref HmacDrbgContext) {.async.} =
           echo "A spam message is found and discarded"
         chat.prompt = false
         showChatPrompt(chat)
-    
+
       echo "rln-relay preparation is in progress..."
 
       let rlnConf = WakuRlnConfig(

apps/chat2bridge/chat2bridge.nim

@@ -288,6 +288,7 @@ when isMainModule:
 
   if conf.filter:
     waitFor mountFilter(bridge.nodev2)
+    waitFor mountLegacyFilter(bridge.nodev2)
 
   if conf.staticnodes.len > 0:
     waitFor connectToNodes(bridge.nodev2, conf.staticnodes)

apps/wakunode2/app.nim

@@ -254,7 +254,7 @@ proc setupDiscoveryV5*(app: App): WakuDiscoveryV5 =
   )
 
   WakuDiscoveryV5.new(
-    app.rng, 
+    app.rng,
     discv5Conf,
     some(app.record),
     some(app.node.peerManager),
@@ -326,7 +326,7 @@ proc setupWakuApp*(app: var App): AppResult[void] =
   ok()
 
 proc getPorts(listenAddrs: seq[MultiAddress]):
-              AppResult[tuple[tcpPort, websocketPort: Option[Port]]] = 
+              AppResult[tuple[tcpPort, websocketPort: Option[Port]]] =
 
   var tcpPort, websocketPort = none(Port)
 
@@ -548,7 +548,15 @@ proc setupProtocols(node: WakuNode,
   # Filter setup. NOTE Must be mounted after relay
   if conf.filter:
     try:
-      await mountFilter(node, filterTimeout = chronos.seconds(conf.filterTimeout))
+      await mountLegacyFilter(node, filterTimeout = chronos.seconds(conf.filterTimeout))
+    except CatchableError:
+      return err("failed to mount waku legacy filter protocol: " & getCurrentExceptionMsg())
+
+    try:
+      await mountFilter(node,
+                        subscriptionTimeout = chronos.seconds(conf.filterSubscriptionTimeout),
+                        maxFilterPeers = conf.filterMaxPeersToServe,
+                        maxFilterCriteriaPerPeer = conf.filterMaxCriteria)
     except CatchableError:
       return err("failed to mount waku filter protocol: " & getCurrentExceptionMsg())
 
@@ -724,7 +732,7 @@ proc startRestServer(app: App, address: IpAddress, port: Port, conf: WakuNodeCon
 
     let filterCache = MessageCache.init()
 
-    let filterDiscoHandler = 
+    let filterDiscoHandler =
       if app.wakuDiscv5.isSome():
         some(defaultDiscoveryHandler(app.wakuDiscv5.get(), Filter))
       else: none(DiscoveryHandler)
@@ -739,7 +747,7 @@ proc startRestServer(app: App, address: IpAddress, port: Port, conf: WakuNodeCon
     notInstalledTab["filter"] = "/filter endpoints are not available. Please check your configuration: --filternode"
 
   ## Store REST API
-  let storeDiscoHandler = 
+  let storeDiscoHandler =
     if app.wakuDiscv5.isSome():
       some(defaultDiscoveryHandler(app.wakuDiscv5.get(), Store))
     else: none(DiscoveryHandler)
@@ -749,7 +757,7 @@ proc startRestServer(app: App, address: IpAddress, port: Port, conf: WakuNodeCon
   ## Light push API
   if conf.lightpushnode  != "" and
      app.node.wakuLightpushClient != nil:
-    let lightDiscoHandler = 
+    let lightDiscoHandler =
       if app.wakuDiscv5.isSome():
         some(defaultDiscoveryHandler(app.wakuDiscv5.get(), Lightpush))
       else: none(DiscoveryHandler)

apps/wakunode2/external_config.nim

@@ -95,6 +95,7 @@ type
         defaultValue: false,
         name: "execute" .}: bool
 
+
     of noCommand:
       ##  Application-level configuration
       protectedTopics* {.
@@ -221,7 +222,7 @@ type
         desc: "Rln relay identity commitment key as a Hex string",
         defaultValue: ""
         name: "rln-relay-id-commitment-key" }: string
-      
+
       rlnRelayTreePath* {.
         desc: "Path to the RLN merkle tree sled db (https://github.com/spacejam/sled)",
         defaultValue: ""
@@ -304,10 +305,25 @@ type
         name: "filternode" }: string
 
       filterTimeout* {.
-        desc: "Timeout for filter node in seconds.",
+        desc: "Filter clients will be wiped out if not able to receive push messages within this timeout. In seconds.",
         defaultValue: 14400 # 4 hours
         name: "filter-timeout" }: int64
 
+      filterSubscriptionTimeout* {.
+        desc: "Timeout for filter subscription without ping or refresh it, in seconds. Only for v2 filter protocol.",
+        defaultValue: 300 # 5 minutes
+        name: "filter-subscription-timeout" }: int64
+
+      filterMaxPeersToServe* {.
+        desc: "Maximum number of peers to serve at a time. Only for v2 filter protocol.",
+        defaultValue: 1000
+        name: "filter-max-peers-to-serve" }: uint32
+
+      filterMaxCriteria* {.
+        desc: "Maximum number of pubsub- and content topic combination per peers at a time. Only for v2 filter protocol.",
+        defaultValue: 1000
+        name: "filter-max-criteria" }: uint32
+
       ## Lightpush config
 
       lightpush* {.