use new nim-metrics API

eth/common/utils.nim

@@ -10,5 +10,5 @@ proc parseAddress*(hexString: string): EthAddress =
 proc `$`*(a: EthAddress): string =
   a.toHex()
 
-var peerGauge* = newGauge("connected_peers", "number of peers in the pool")
+newPublicGauge(connected_peers, "number of peers in the pool")
 

eth/p2p/peer_pool.nim

@@ -110,8 +110,7 @@ proc getRandomBootnode(p: PeerPool): Option[Node] =
 proc addPeer*(pool: PeerPool, peer: Peer) {.gcsafe.} =
   doAssert(peer.remote notin pool.connectedNodes)
   pool.connectedNodes[peer.remote] = peer
-  {.gcsafe.}:
-    peerGauge.inc()
+  connected_peers.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

@@ -795,8 +795,7 @@ 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)
-    {.gcsafe.}:
-      peerGauge.dec()
+    connected_peers.dec()
 
     # Note: we need to do this check as disconnect (and thus removePeer)
     # currently can get called before the dispatcher is initialized.