p2p: log as debug msg when address dialing is already connected (#4082)

Fixes #3991

CHANGELOG_PENDING.md

@@ -22,6 +22,7 @@ program](https://hackerone.com/tendermint).
 
 - [mempool] [\#4057](https://github.com/tendermint/tendermint/issues/4057) Include peer ID when logging rejected txns (@erikgrinaker)
 - [tools] [\#4023](https://github.com/tendermint/tendermint/issues/4023) Improved `tm-monitor` formatting of start time and avg tx throughput (@erikgrinaker)
+- [p2p] [\#3991](https://github.com/tendermint/tendermint/issues/3991) Log "has been established or dialed" as debug log instead of Error for connected peers (@whunmr)
 
 ### BUG FIXES:
 

p2p/pex/pex_reactor.go

@@ -368,7 +368,7 @@ func (r *PEXReactor) ReceiveAddrs(addrs []*p2p.NetAddress, src Peer) error {
 				err := r.dialPeer(addr)
 				if err != nil {
 					switch err.(type) {
-					case errMaxAttemptsToDial, errTooEarlyToDial:
+					case errMaxAttemptsToDial, errTooEarlyToDial, p2p.ErrCurrentlyDialingOrExistingAddress:
 						r.Logger.Debug(err.Error(), "addr", addr)
 					default:
 						r.Logger.Error(err.Error(), "addr", addr)
@@ -590,7 +590,9 @@ func (r *PEXReactor) dialSeeds() {
 		// dial a random seed
 		seedAddr := r.seedAddrs[i]
 		err := r.Switch.DialPeerWithAddress(seedAddr)
-		if err == nil {
+
+		switch err.(type) {
+		case nil, p2p.ErrCurrentlyDialingOrExistingAddress:
 			return
 		}
 		r.Switch.Logger.Error("Error dialing seed", "err", err, "seed", seedAddr)
@@ -676,7 +678,7 @@ func (r *PEXReactor) crawlPeers(addrs []*p2p.NetAddress) {
 		err := r.dialPeer(addr)
 		if err != nil {
 			switch err.(type) {
-			case errMaxAttemptsToDial, errTooEarlyToDial:
+			case errMaxAttemptsToDial, errTooEarlyToDial, p2p.ErrCurrentlyDialingOrExistingAddress:
 				r.Logger.Debug(err.Error(), "addr", addr)
 			default:
 				r.Logger.Error(err.Error(), "addr", addr)