node: include and log TxHash field in SignedObservation

Optional metadata for debugging. Allows tying a received observation
to an on-chain transaction even if the node missed the observation.

Change-Id: Ie50c10c8ab7f65469555674d90645f91092fb2e3

node/pkg/processor/broadcast.go

@@ -22,7 +22,7 @@ var (
 		})
 )
 
-func (p *Processor) broadcastSignature(v *vaa.VAA, signature []byte) {
+func (p *Processor) broadcastSignature(v *vaa.VAA, signature []byte, txhash []byte) {
 	digest, err := v.SigningMsg()
 	if err != nil {
 		panic(err)
@@ -32,6 +32,7 @@ func (p *Processor) broadcastSignature(v *vaa.VAA, signature []byte) {
 		Addr:      crypto.PubkeyToAddress(p.gk.PublicKey).Bytes(),
 		Hash:      digest.Bytes(),
 		Signature: signature,
+		TxHash:    txhash,
 	}
 
 	w := gossipv1.GossipMessage{Message: &gossipv1.GossipMessage_SignedObservation{SignedObservation: &obsv}}

node/pkg/processor/injection.go

@@ -44,5 +44,5 @@ func (p *Processor) handleInjection(ctx context.Context, v *vaa.VAA) {
 		zap.String("signature", hex.EncodeToString(s)))
 
 	vaaInjectionsTotal.Inc()
-	p.broadcastSignature(v, s)
+	p.broadcastSignature(v, s, nil)
 }

node/pkg/processor/message.go

@@ -98,5 +98,5 @@ func (p *Processor) handleMessage(ctx context.Context, k *common.MessagePublicat
 
 	p.attestationEvents.ReportMessagePublication(&reporter.MessagePublication{VAA: *v, InitiatingTxID: k.TxHash})
 
-	p.broadcastSignature(v, s)
+	p.broadcastSignature(v, s, k.TxHash.Bytes())
 }

node/pkg/processor/observation.go

@@ -7,6 +7,7 @@ import (
 	node_common "github.com/certusone/wormhole/node/pkg/common"
 	"github.com/certusone/wormhole/node/pkg/db"
 	"github.com/certusone/wormhole/node/pkg/reporter"
+	"github.com/mr-tron/base58"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"time"
@@ -55,7 +56,10 @@ func (p *Processor) handleObservation(ctx context.Context, m *gossipv1.SignedObs
 	p.logger.Info("received observation",
 		zap.String("digest", hash),
 		zap.String("signature", hex.EncodeToString(m.Signature)),
-		zap.String("addr", hex.EncodeToString(m.Addr)))
+		zap.String("addr", hex.EncodeToString(m.Addr)),
+		zap.String("txhash", hex.EncodeToString(m.TxHash)),
+		zap.String("txhash_b58", base58.Encode(m.TxHash)),
+		)
 
 	observationsReceivedTotal.Inc()
 

proto/gossip/v1/gossip.proto

@@ -78,6 +78,9 @@ message SignedObservation {
   bytes hash = 2;
   // ECSDA signature of the hash using the node's guardian key.
   bytes signature = 3;
+  // Transaction hash this observation was made from.
+  // Optional, included for observability.
+  bytes tx_hash = 4;
 }
 
 // A SignedVAAWithQuorum message is sent by nodes whenever one of the VAAs they observed