use nim-metrics

eth.nimble

@@ -13,7 +13,8 @@ requires "nim >= 0.19.0",
          "chronicles",
          "stew",
          "result",
-         "nat_traversal"
+         "nat_traversal",
+         "https://github.com/status-im/nim-metrics"
 
 proc runTest(path: string) =
   echo "\nRunning: ", path

eth/common/eth_types.nim

@@ -168,9 +168,6 @@ type
     OK
     Error
 
-  NimbusStats* = object
-    num_peers*: int
-
 when BlockNumber is int64:
   ## The goal of these templates is to make it easier to switch
   ## the block number type to a different representation

eth/common/utils.nim

@@ -1,4 +1,6 @@
-import nimcrypto, hashes, stew/byteutils, eth_types
+import nimcrypto, hashes, stew/byteutils, eth_types, metrics
+
+export metrics
 
 proc hash*(d: MDigest): Hash {.inline.} = hash(d.data)
 
@@ -8,5 +10,5 @@ proc parseAddress*(hexString: string): EthAddress =
 proc `$`*(a: EthAddress): string =
   a.toHex()
 
-var nimbusStats*: NimbusStats
+var peerGauge* = newGauge("connected peers", "number of peers in the pool")
 

eth/p2p/peer_pool.nim

@@ -107,10 +107,11 @@ proc getRandomBootnode(p: PeerPool): Option[Node] =
   if p.discovery.bootstrapNodes.len != 0:
     result = option(p.discovery.bootstrapNodes.rand())
 
-proc addPeer*(pool: PeerPool, peer: Peer) =
+proc addPeer*(pool: PeerPool, peer: Peer) {.gcsafe.} =
   doAssert(peer.remote notin pool.connectedNodes)
   pool.connectedNodes[peer.remote] = peer
-  inc(nimbusStats.num_peers)
+  {.gcsafe.}:
+    peerGauge.inc()
   for o in pool.observers.values:
     if not o.onPeerConnected.isNil:
       if o.protocol.isNil or peer.supports(o.protocol):

eth/p2p/rlpx.nim

@@ -795,7 +795,8 @@ proc removePeer(network: EthereumNode, peer: Peer) =
   # between which side disconnects first.
   if network.peerPool != nil and not peer.remote.isNil and peer.remote in network.peerPool.connectedNodes:
     network.peerPool.connectedNodes.del(peer.remote)
-    dec(nimbusStats.num_peers)
+    {.gcsafe.}:
+      peerGauge.dec()
 
     # Note: we need to do this check as disconnect (and thus removePeer)
     # currently can get called before the dispatcher is initialized.