Start relay protocol on wakunode2 (#446)

* Start relay protocol on wakunode2

tests/v2/test_wakunode.nim

@@ -10,6 +10,7 @@ import
   libp2p/switch,
   libp2p/protocols/pubsub/rpc/messages,
   libp2p/protocols/pubsub/pubsub,
+  libp2p/protocols/pubsub/gossipsub,
   eth/keys,
   ../../waku/v2/protocol/[waku_relay, waku_message, message_notifier],
   ../../waku/v2/protocol/waku_store/waku_store,
@@ -394,7 +395,8 @@ procSuite "WakuNode":
     await node1.stop()
     await node2.stop()
     await node3.stop()
-asyncTest "testing rln-relay with mocked zkp":
+  
+  asyncTest "testing rln-relay with mocked zkp":
     
     let
       # publisher node
@@ -449,3 +451,41 @@ asyncTest "testing rln-relay with mocked zkp":
     await node1.stop()
     await node2.stop()
     await node3.stop()
+
+  asyncTest "Relay protocol is started correctly":
+    let
+      nodeKey1 = crypto.PrivateKey.random(Secp256k1, rng[])[]
+      node1 = WakuNode.init(nodeKey1, ValidIpAddress.init("0.0.0.0"),
+        Port(60000))
+
+    # Relay protocol starts if mounted after node start
+
+    await node1.start()
+
+    node1.mountRelay()
+
+    check:
+      GossipSub(node1.wakuRelay).heartbeatFut.isNil == false
+
+    # Relay protocol starts if mounted before node start
+
+    let
+      nodeKey2 = crypto.PrivateKey.random(Secp256k1, rng[])[]
+      node2 = WakuNode.init(nodeKey2, ValidIpAddress.init("0.0.0.0"),
+        Port(60002))
+
+    node2.mountRelay()
+
+    check:
+      # Relay has not yet started as node has not yet started
+      GossipSub(node2.wakuRelay).heartbeatFut.isNil
+    
+    await node2.start()
+
+    check:
+      # Relay started on node start
+      GossipSub(node2.wakuRelay).heartbeatFut.isNil == false
+    
+    await allFutures([node1.stop(), node2.stop()])
+
+

waku/v2/node/wakunode2.nim

@@ -66,6 +66,7 @@ type
     filters*: Filters
     subscriptions*: MessageNotificationSubscriptions
     rng*: ref BrHmacDrbgContext
+    started*: bool # Indicates that node has started listening
 
 # NOTE Any difference here in Waku vs Eth2?
 # E.g. Devp2p/Libp2p support, etc.
@@ -162,12 +163,19 @@ proc start*(node: WakuNode) {.async.} =
   ## XXX: this should be /ip4..., / stripped?
   info "Listening on", full = listenStr
 
+  if not node.wakuRelay.isNil:
+    await node.wakuRelay.start()
+  
+  node.started = true
+
 proc stop*(node: WakuNode) {.async.} =
   if not node.wakuRelay.isNil:
     await node.wakuRelay.stop()
 
   await node.switch.stop()
 
+  node.started = false
+
 proc subscribe*(node: WakuNode, topic: Topic, handler: TopicHandler) =
   ## Subscribes to a PubSub topic. Triggers handler when receiving messages on
   ## this topic. TopicHandler is a method that takes a topic and some data.
@@ -415,6 +423,13 @@ proc mountRelay*(node: WakuNode, topics: seq[string] = newSeq[string](), rlnRela
     # TODO currently the message validator is set for the defaultTopic, this can be configurable to accept other pubsub topics as well 
     addRLNRelayValidator(node, defaultTopic)
     info "WakuRLNRelay is mounted successfully"
+  
+  if node.started:
+    # Node has already started. Start the WakuRelay protocol
+
+    waitFor node.wakuRelay.start()
+
+    info "relay mounted and started successfully"
 
 
 ## Helpers