libwaku: exposing more features (#3003)

- Allow to start or store discv5
- Expose lightpush request operation
- Expose list of connected and mesh peers
- Expose store client

library/libwaku.h

@@ -75,6 +75,12 @@ int waku_relay_publish(void* ctx,
                        WakuCallBack callback,
                        void* userData);
 
+int waku_lightpush_publish(void* ctx,
+                       const char* pubSubTopic,
+                       const char* jsonWakuMessage,
+                       WakuCallBack callback,
+                       void* userData);
+
 int waku_relay_subscribe(void* ctx,
                          const char* pubSubTopic,
                          WakuCallBack callback,
@@ -85,6 +91,23 @@ int waku_relay_unsubscribe(void* ctx,
                            WakuCallBack callback,
                            void* userData);
 
+int waku_relay_get_num_connected_peers(void* ctx,
+                           const char* pubSubTopic,
+                           WakuCallBack callback,
+                           void* userData);
+
+int waku_relay_get_num_peers_in_mesh(void* ctx,
+                           const char* pubSubTopic,
+                           WakuCallBack callback,
+                           void* userData);
+
+int waku_store_query(void* ctx,
+                        const char* jsonQuery,
+                        const char* peerAddr,
+                        int timeoutMs,
+                        WakuCallBack callback,
+                        void* userData);
+
 int waku_connect(void* ctx,
                  const char* peerMultiAddr,
                  unsigned int timeoutMs,
@@ -114,6 +137,14 @@ int waku_discv5_update_bootnodes(void* ctx,
                                  WakuCallBack callback,
                                  void* userData);
 
+int waku_start_discv5(void* ctx,
+                      WakuCallBack callback,
+                      void* userData);
+
+int waku_stop_discv5(void* ctx,
+                     WakuCallBack callback,
+                     void* userData);
+
 // Retrieves the ENR information
 int waku_get_my_enr(void* ctx,
                     WakuCallBack callback,

library/libwaku.nim

@@ -19,6 +19,7 @@ import
   ./waku_thread/inter_thread_communication/requests/peer_manager_request,
   ./waku_thread/inter_thread_communication/requests/protocols/relay_request,
   ./waku_thread/inter_thread_communication/requests/protocols/store_request,
+  ./waku_thread/inter_thread_communication/requests/protocols/lightpush_request,
   ./waku_thread/inter_thread_communication/requests/debug_node_request,
   ./waku_thread/inter_thread_communication/requests/discovery_request,
   ./waku_thread/inter_thread_communication/waku_thread_request,
@@ -383,6 +384,119 @@ proc waku_relay_unsubscribe(
 
   return RET_OK
 
+proc waku_relay_get_num_connected_peers(
+    ctx: ptr Context, pubSubTopic: cstring, callback: WakuCallBack, userData: pointer
+): cint {.dynlib, exportc.} =
+  ctx[].userData = userData
+
+  let pst = pubSubTopic.alloc()
+  defer:
+    deallocShared(pst)
+
+  let numConnPeersRes = waku_thread.sendRequestToWakuThread(
+    ctx,
+    RequestType.RELAY,
+    RelayRequest.createShared(RelayMsgType.LIST_CONNECTED_PEERS, PubsubTopic($pst)),
+  )
+
+  if numConnPeersRes.isErr():
+    foreignThreadGc:
+      let msg = "Error in waku_relay_get_num_connected_peers: " & $numConnPeersRes.error
+      callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+      return RET_ERR
+
+  let numConnPeers = numConnPeersRes.get()
+  foreignThreadGc:
+    callback(
+      RET_OK, unsafeAddr numConnPeers[0], cast[csize_t](len(numConnPeers)), userData
+    )
+
+  return RET_OK
+
+proc waku_relay_get_num_peers_in_mesh(
+    ctx: ptr Context, pubSubTopic: cstring, callback: WakuCallBack, userData: pointer
+): cint {.dynlib, exportc.} =
+  ctx[].userData = userData
+
+  let pst = pubSubTopic.alloc()
+  defer:
+    deallocShared(pst)
+
+  let numPeersInMeshRes = waku_thread.sendRequestToWakuThread(
+    ctx,
+    RequestType.RELAY,
+    RelayRequest.createShared(RelayMsgType.LIST_MESH_PEERS, PubsubTopic($pst)),
+  )
+
+  if numPeersInMeshRes.isErr():
+    foreignThreadGc:
+      let msg = "Error in waku_relay_get_num_peers_in_mesh: " & $numPeersInMeshRes.error
+      callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+      return RET_ERR
+
+  let numPeersInMesh = numPeersInMeshRes.get()
+  foreignThreadGc:
+    callback(
+      RET_OK, unsafeAddr numPeersInMesh[0], cast[csize_t](len(numPeersInMesh)), userData
+    )
+
+  return RET_OK
+
+proc waku_lightpush_publish(
+    ctx: ptr Context,
+    pubSubTopic: cstring,
+    jsonWakuMessage: cstring,
+    callback: WakuCallBack,
+    userData: pointer,
+): cint {.dynlib, exportc, cdecl.} =
+  ctx[].userData = userData
+
+  if isNil(callback):
+    return RET_MISSING_CALLBACK
+
+  let jwm = jsonWakuMessage.alloc()
+  let pst = pubSubTopic.alloc()
+  defer:
+    deallocShared(jwm)
+    deallocShared(pst)
+
+  var jsonMessage: JsonMessage
+  try:
+    let jsonContent = parseJson($jwm)
+    jsonMessage = JsonMessage.fromJsonNode(jsonContent)
+  except JsonParsingError:
+    let msg = fmt"Error parsing json message: {getCurrentExceptionMsg()}"
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let wakuMessage = jsonMessage.toWakuMessage().valueOr:
+    let msg = fmt"Problem building the WakuMessage: {error}"
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let targetPubSubTopic =
+    if len(pst) == 0:
+      DefaultPubsubTopic
+    else:
+      $pst
+
+  let sendReqRes = waku_thread.sendRequestToWakuThread(
+    ctx,
+    RequestType.LIGHTPUSH,
+    LightpushRequest.createShared(
+      LightpushMsgType.PUBLISH, PubsubTopic($pst), wakuMessage
+    ),
+  )
+
+  if sendReqRes.isErr():
+    let msg = $sendReqRes.error
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let msg = $sendReqRes.value
+  callback(RET_OK, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+  return RET_OK
+
 proc waku_connect(
     ctx: ptr Context,
     peerMultiAddr: cstring,
@@ -408,21 +522,30 @@ proc waku_connect(
 
 proc waku_store_query(
     ctx: ptr Context,
-    queryJson: cstring,
+    jsonQuery: cstring,
-    peerId: cstring,
+    peerAddr: cstring,
     timeoutMs: cint,
     callback: WakuCallBack,
     userData: pointer,
 ): cint {.dynlib, exportc.} =
   ctx[].userData = userData
 
-  ## TODO: implement the logic that make the "self" node to act as a Store client
+  if isNil(callback):
+    return RET_MISSING_CALLBACK
 
-  # if sendReqRes.isErr():
+  let sendReqRes = waku_thread.sendRequestToWakuThread(
-  #   let msg = $sendReqRes.error
+    ctx,
-  #   callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)))
+    RequestType.STORE,
-  #   return RET_ERR
+    JsonStoreQueryRequest.createShared(jsonQuery, peerAddr, timeoutMs, callback),
+  )
 
+  if sendReqRes.isErr():
+    let msg = $sendReqRes.error
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let msg = $sendReqRes.value
+  callback(RET_OK, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
   return RET_OK
 
 proc waku_listen_addresses(
@@ -510,5 +633,39 @@ proc waku_get_my_enr(
     callback(RET_OK, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
     return RET_OK
 
+proc waku_start_discv5(
+    ctx: ptr Context, callback: WakuCallBack, userData: pointer
+): cint {.dynlib, exportc.} =
+  ctx[].userData = userData
+
+  let resp = waku_thread.sendRequestToWakuThread(
+    ctx, RequestType.DISCOVERY, DiscoveryRequest.createDiscV5StartRequest()
+  ).valueOr:
+    let msg = $error
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let msg = $resp
+  callback(RET_OK, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+
+  return RET_OK
+
+proc waku_stop_discv5(
+    ctx: ptr Context, callback: WakuCallBack, userData: pointer
+): cint {.dynlib, exportc.} =
+  ctx[].userData = userData
+
+  let resp = waku_thread.sendRequestToWakuThread(
+    ctx, RequestType.DISCOVERY, DiscoveryRequest.createDiscV5StopRequest()
+  ).valueOr:
+    let msg = $error
+    callback(RET_ERR, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+    return RET_ERR
+
+  let msg = $resp
+  callback(RET_OK, unsafeAddr msg[0], cast[csize_t](len(msg)), userData)
+
+  return RET_OK
+
 ### End of exported procs
 ################################################################################

library/waku_thread/inter_thread_communication/requests/discovery_request.nim

@@ -10,6 +10,8 @@ import
 type DiscoveryMsgType* = enum
   GET_BOOTSTRAP_NODES
   UPDATE_DISCV5_BOOTSTRAP_NODES
+  START_DISCV5
+  STOP_DISCV5
 
 type DiscoveryRequest* = object
   operation: DiscoveryMsgType
@@ -52,6 +54,12 @@ proc createUpdateBootstrapNodesRequest*(
 ): ptr type T =
   return T.createShared(op, "", "", 0, nodes)
 
+proc createDiscV5StartRequest*(T: type DiscoveryRequest): ptr type T =
+  return T.createShared(START_DISCV5, "", "", 0, "")
+
+proc createDiscV5StopRequest*(T: type DiscoveryRequest): ptr type T =
+  return T.createShared(STOP_DISCV5, "", "", 0, "")
+
 proc destroyShared(self: ptr DiscoveryRequest) =
   deallocShared(self[].enrTreeUrl)
   deallocShared(self[].nameDnsServer)
@@ -86,6 +94,16 @@ proc process*(
     destroyShared(self)
 
   case self.operation
+  of START_DISCV5:
+    let res = await waku.wakuDiscv5.start()
+    res.isOkOr:
+      return err($error)
+
+    return ok("discv5 started correctly")
+  of STOP_DISCV5:
+    await waku.wakuDiscv5.stop()
+
+    return ok("discv5 stopped correctly")
   of GET_BOOTSTRAP_NODES:
     let nodes = retrieveBootstrapNodes($self[].enrTreeUrl, $self[].nameDnsServer).valueOr:
       return err($error)

library/waku_thread/inter_thread_communication/requests/protocols/lightpush_request.nim

@@ -0,0 +1,103 @@
+import std/net, options
+import chronicles, chronos, stew/byteutils, results
+import
+  ../../../../../waku/waku_core/message/message,
+  ../../../../../waku/factory/waku,
+  ../../../../../waku/waku_core/message,
+  ../../../../../waku/waku_core/time, # Timestamp
+  ../../../../../waku/waku_core/topics/pubsub_topic,
+  ../../../../../waku/waku_lightpush/client,
+  ../../../../../waku/waku_lightpush/common,
+  ../../../../../waku/node/peer_manager/peer_manager,
+  ../../../../alloc
+
+type LightpushMsgType* = enum
+  PUBLISH
+
+type ThreadSafeWakuMessage* = object
+  payload: SharedSeq[byte]
+  contentTopic: cstring
+  meta: SharedSeq[byte]
+  version: uint32
+  timestamp: Timestamp
+  ephemeral: bool
+  when defined(rln):
+    proof: SharedSeq[byte]
+
+type LightpushRequest* = object
+  operation: LightpushMsgType
+  pubsubTopic: cstring
+  message: ThreadSafeWakuMessage # only used in 'PUBLISH' requests
+
+proc createShared*(
+    T: type LightpushRequest,
+    op: LightpushMsgType,
+    pubsubTopic: PubsubTopic,
+    m = WakuMessage(),
+): ptr type T =
+  var ret = createShared(T)
+  ret[].operation = op
+  ret[].pubsubTopic = pubsubTopic.alloc()
+  ret[].message = ThreadSafeWakuMessage(
+    payload: allocSharedSeq(m.payload),
+    contentTopic: m.contentTopic.alloc(),
+    meta: allocSharedSeq(m.meta),
+    version: m.version,
+    timestamp: m.timestamp,
+    ephemeral: m.ephemeral,
+  )
+  when defined(rln):
+    ret[].message.proof = allocSharedSeq(m.proof)
+
+  return ret
+
+proc destroyShared(self: ptr LightpushRequest) =
+  deallocSharedSeq(self[].message.payload)
+  deallocShared(self[].message.contentTopic)
+  deallocSharedSeq(self[].message.meta)
+  when defined(rln):
+    deallocSharedSeq(self[].message.proof)
+
+  deallocShared(self)
+
+proc toWakuMessage(m: ThreadSafeWakuMessage): WakuMessage =
+  var wakuMessage = WakuMessage()
+
+  wakuMessage.payload = m.payload.toSeq()
+  wakuMessage.contentTopic = $m.contentTopic
+  wakuMessage.meta = m.meta.toSeq()
+  wakuMessage.version = m.version
+  wakuMessage.timestamp = m.timestamp
+  wakuMessage.ephemeral = m.ephemeral
+
+  when defined(rln):
+    wakuMessage.proof = m.proof
+
+  return wakuMessage
+
+proc process*(
+    self: ptr LightpushRequest, waku: ptr Waku
+): Future[Result[string, string]] {.async.} =
+  defer:
+    destroyShared(self)
+
+  case self.operation
+  of PUBLISH:
+    let msg = self.message.toWakuMessage()
+    let pubsubTopic = $self.pubsubTopic
+
+    if waku.node.wakuLightpushClient.isNil():
+      return err("LightpushRequest waku.node.wakuLightpushClient is nil")
+
+    let peerOpt = waku.node.peerManager.selectPeer(WakuLightPushCodec)
+    if peerOpt.isNone():
+      return err("failed to lightpublish message, no suitable remote peers")
+
+    (
+      await waku.node.wakuLightpushClient.publish(
+        pubsubTopic, msg, peer = peerOpt.get()
+      )
+    ).isOkOr:
+      return err("LightpushRequest error publishing: " & $error)
+
+  return ok("")

library/waku_thread/inter_thread_communication/requests/protocols/relay_request.nim

@@ -13,6 +13,10 @@ type RelayMsgType* = enum
   SUBSCRIBE
   UNSUBSCRIBE
   PUBLISH
+  LIST_CONNECTED_PEERS
+    ## to return the list of all connected peers to an specific pubsub topic
+  LIST_MESH_PEERS
+    ## to return the list of only the peers that conform the mesh for a particular pubsub topic
 
 type ThreadSafeWakuMessage* = object
   payload: SharedSeq[byte]
@@ -104,5 +108,13 @@ proc process*(
     elif numPeers > 0:
       let msgHash = computeMessageHash(pubSubTopic, msg).to0xHex
       return ok(msgHash)
+  of LIST_CONNECTED_PEERS:
+    let numConnPeers = waku.node.wakuRelay.getNumConnectedPeers($self.pubsubTopic).valueOr:
+      return err($error)
+    return ok($numConnPeers)
+  of LIST_MESH_PEERS:
+    let numPeersInMesh = waku.node.wakuRelay.getNumPeersInMesh($self.pubsubTopic).valueOr:
+      return err($error)
+    return ok($numPeersInMesh)
 
   return ok("")

library/waku_thread/inter_thread_communication/requests/protocols/store_request.nim

@@ -1,12 +1,21 @@
+import std/[json, sugar, options]
 import chronos, results
-import ../../../../../waku/factory/waku, ../../../../alloc, ../../../../callback
+import
+  ../../../../../waku/factory/waku,
+  ../../../../alloc,
+  ../../../../callback,
+  ../../../../../waku/waku_core/peers,
+  ../../../../../waku/waku_core/time,
+  ../../../../../waku/waku_core/message/digest,
+  ../../../../../waku/waku_store/common,
+  ../../../../../waku/waku_store/client,
+  ../../../../../waku/common/paging
 
 type StoreReqType* = enum
   REMOTE_QUERY ## to perform a query to another Store node
-  LOCAL_QUERY ## to retrieve the data from 'self' node
 
-type StoreQueryRequest* = object
+type JsonStoreQueryRequest* = object
-  queryJson: cstring
+  jsonQuery: cstring
   peerAddr: cstring
   timeoutMs: cint
   storeCallback: WakuCallBack
@@ -15,38 +24,119 @@ type StoreRequest* = object
   operation: StoreReqType
   storeReq: pointer
 
-proc createShared*(
+func fromJsonNode(
-    T: type StoreRequest, operation: StoreReqType, request: pointer
+    T: type JsonStoreQueryRequest, jsonContent: JsonNode
-): ptr type T =
+): StoreQueryRequest =
-  var ret = createShared(T)
+  let contentTopics = collect(newSeq):
-  ret[].request = request
+    for cTopic in jsonContent["content_topics"].getElems():
-  return ret
+      cTopic.getStr()
+
+  let msgHashes = collect(newSeq):
+    for hashJsonObj in jsonContent["message_hashes"].getElems():
+      var hash: WakuMessageHash
+      var count: int = 0
+      for byteValue in hashJsonObj.getElems():
+        hash[count] = byteValue.getInt().byte
+        count.inc()
+
+      hash
+
+  let pubsubTopic =
+    if jsonContent.contains("pubsub_topic"):
+      some(jsonContent["pubsub_topic"].getStr())
+    else:
+      none(string)
+
+  let startTime =
+    if jsonContent.contains("time_start"):
+      some(Timestamp(jsonContent["time_start"].getInt()))
+    else:
+      none(Timestamp)
+
+  let endTime =
+    if jsonContent.contains("time_end"):
+      some(Timestamp(jsonContent["time_end"].getInt()))
+    else:
+      none(Timestamp)
+
+  let paginationCursor =
+    if jsonContent.contains("pagination_cursor"):
+      var hash: WakuMessageHash
+      var count: int = 0
+      for byteValue in jsonContent["pagination_cursor"].getElems():
+        hash[count] = byteValue.getInt().byte
+        count.inc()
+
+      some(hash)
+    else:
+      none(WakuMessageHash)
+
+  let paginationForwardBool = jsonContent["pagination_forward"].getBool()
+  let paginationForward =
+    if paginationForwardBool: PagingDirection.FORWARD else: PagingDirection.BACKWARD
+
+  let paginationLimit =
+    if jsonContent.contains("pagination_limit"):
+      some(uint64(jsonContent["pagination_limit"].getInt()))
+    else:
+      none(uint64)
+
+  return StoreQueryRequest(
+    requestId: jsonContent["request_id"].getStr(),
+    includeData: jsonContent["include_data"].getBool(),
+    pubsubTopic: pubsubTopic,
+    contentTopics: contentTopics,
+    startTime: startTime,
+    endTime: endTime,
+    messageHashes: msgHashes,
+    paginationCursor: paginationCursor,
+    paginationForward: paginationForward,
+    paginationLimit: paginationLimit,
+  )
 
 proc createShared*(
-    T: type StoreQueryRequest,
+    T: type JsonStoreQueryRequest,
-    queryJson: cstring,
+    jsonQuery: cstring,
     peerAddr: cstring,
     timeoutMs: cint,
     storeCallback: WakuCallBack = nil,
 ): ptr type T =
   var ret = createShared(T)
   ret[].timeoutMs = timeoutMs
-  ret[].queryJson = queryJson.alloc()
+  ret[].jsonQuery = jsonQuery.alloc()
   ret[].peerAddr = peerAddr.alloc()
   ret[].storeCallback = storeCallback
   return ret
 
-proc destroyShared(self: ptr StoreQueryRequest) =
+proc destroyShared(self: ptr JsonStoreQueryRequest) =
-  deallocShared(self[].queryJson)
+  deallocShared(self[].jsonQuery)
   deallocShared(self[].peerAddr)
   deallocShared(self)
 
 proc process(
-    self: ptr StoreQueryRequest, waku: ptr Waku
+    self: ptr JsonStoreQueryRequest, waku: ptr Waku
 ): Future[Result[string, string]] {.async.} =
   defer:
     destroyShared(self)
 
+  let jsonContentRes = catch:
+    parseJson($self[].jsonQuery)
+
+  if jsonContentRes.isErr():
+    return err(
+      "JsonStoreQueryRequest failed parsing store request: " & jsonContentRes.error.msg
+    )
+
+  let storeQueryRequest = JsonStoreQueryRequest.fromJsonNode(jsonContentRes.get())
+
+  let peer = peers.parsePeerInfo($self[].peerAddr).valueOr:
+    return err("JsonStoreQueryRequest failed to parse peer addr: " & $error)
+
+  let queryResponse = (await waku.node.wakuStoreClient.query(storeQueryRequest, peer)).valueOr:
+    return err("JsonStoreQueryRequest failed store query: " & $error)
+
+  return ok($(%*queryResponse)) ## returning the response in json format
+
 proc process*(
     self: ptr StoreRequest, waku: ptr Waku
 ): Future[Result[string, string]] {.async.} =
@@ -55,9 +145,6 @@ proc process*(
 
   case self.operation
   of REMOTE_QUERY:
-    return await cast[ptr StoreQueryRequest](self[].storeReq).process(waku)
+    return await cast[ptr JsonStoreQueryRequest](self[].storeReq).process(waku)
-  of LOCAL_QUERY:
-    discard
-    # cast[ptr StoreQueryRequest](request[].reqContent).process(node)
 
-  return ok("")
+  return err("store request not handled at all")

library/waku_thread/inter_thread_communication/waku_thread_request.nim

@@ -10,6 +10,7 @@ import
   ./requests/peer_manager_request,
   ./requests/protocols/relay_request,
   ./requests/protocols/store_request,
+  ./requests/protocols/lightpush_request,
   ./requests/debug_node_request,
   ./requests/discovery_request
 
@@ -20,6 +21,7 @@ type RequestType* {.pure.} = enum
   STORE
   DEBUG
   DISCOVERY
+  LIGHTPUSH
 
 type InterThreadRequest* = object
   reqType: RequestType
@@ -56,6 +58,8 @@ proc process*(
       cast[ptr DebugNodeRequest](request[].reqContent).process(waku[])
     of DISCOVERY:
       cast[ptr DiscoveryRequest](request[].reqContent).process(waku)
+    of LIGHTPUSH:
+      cast[ptr LightpushRequest](request[].reqContent).process(waku)
 
   return await retFut
 

waku/waku_relay/protocol.nim

@@ -453,3 +453,44 @@ proc publish*(
       obs.onMessagePublished(pubSubTopic, message)
 
   return relayedPeerCount
+
+proc getNumPeersInMesh*(w: WakuRelay, pubsubTopic: PubsubTopic): Result[int, string] =
+  ## Returns the number of peers in a mesh defined by the passed pubsub topic.
+  ## The 'mesh' atribute is defined in the GossipSub ref object.
+
+  if not w.mesh.hasKey(pubsubTopic):
+    return err(
+      "getNumPeersInMesh - there is no mesh peer for the given pubsub topic: " &
+        pubsubTopic
+    )
+
+  let peersRes = catch:
+    w.mesh[pubsubTopic]
+
+  let peers: HashSet[PubSubPeer] = peersRes.valueOr:
+    return
+      err("getNumPeersInMesh - exception accessing " & pubsubTopic & ": " & error.msg)
+
+  return ok(peers.len)
+
+proc getNumConnectedPeers*(
+    w: WakuRelay, pubsubTopic: PubsubTopic
+): Result[int, string] =
+  ## Returns the number of connected peers and subscribed to the passed pubsub topic.
+  ## The 'gossipsub' atribute is defined in the GossipSub ref object.
+
+  if not w.gossipsub.hasKey(pubsubTopic):
+    return err(
+      "getNumConnectedPeers - there is no gossipsub peer for the given pubsub topic: " &
+        pubsubTopic
+    )
+
+  let peersRes = catch:
+    w.gossipsub[pubsubTopic]
+
+  let peers: HashSet[PubSubPeer] = peersRes.valueOr:
+    return err(
+      "getNumConnectedPeers - exception accessing " & pubsubTopic & ": " & error.msg
+    )
+
+  return ok(peers.len)