From 5e009ee6d903abe066f1f170323c73a6d20144ae Mon Sep 17 00:00:00 2001
From: Bartosz Lenart <lenart.consulting@gmail.com>
Date: Wed, 6 Mar 2024 16:27:20 +0100
Subject: [PATCH] 380: Get lacking parent vertex from the connected nodes.
 (#382)

---
 artefacts/test_wallet                  | Bin 175 -> 175 bytes
 protobuf/gossip.proto                  |   1 +
 src/accountant/accountant.go           |  13 ++-
 src/accountant/replier.go              |   4 +-
 src/cmd/wallet/main.go                 |  14 +--
 src/gossip/gossip.go                   | 115 +++++++++++++++++++------
 src/protobufcompiled/gossip.pb.go      |  37 ++++----
 src/protobufcompiled/gossip_grpc.pb.go |  36 ++++++++
 src/spice/spice.go                     |  10 ---
 src/spice/spice_test.go                |  22 -----
 10 files changed, 171 insertions(+), 81 deletions(-)

diff --git a/artefacts/test_wallet b/artefacts/test_wallet
index a65ffa1cef13d2051581bc5226e702a0ce8053c9..7c0755f439d74004780f0fde932d373410ff8af4 100644
GIT binary patch
literal 175
zcmV;g08sx(Cyw&YW-IGVU})@=|9YK!GFAWPffXT`NZOW*5!N!-MSH}Yz$^XVoe(gb
zb_8-}lt0=;?U|3U>FtRak3V`-ZVy#ylq*7Xl^l=9yUdbmSh_;>VY0>5`KpO+!p9Mm
zta)M8p>rer)z7U<rrE}b2rwXBYO=`MGk>y^1`vpGoz7TP**R;(!k&TH`!6QjKuh()
deRCYsz`#R1Pc$m%NLtTis~ak{w6JcE^~Y_UTekoJ

literal 175
zcmV;g08szUc4q}b7g7R^<8oPDXtaz&Q-#`5LV#4CIR)u06SZc0K~PVYsXFruUH6UK
zaYqaRKiUhfc9+wa>OTNwpq2e~4MQoq^PG$anz?_JVQWZa-j8}-nK^%5O9L)wSohSj
zRlRG3^v+d9c)SIXvyh?&0GJr-?@c~)NzazC7;vv(tM$^UIhm!}Hna+LZ?j^72seWo
dsE}Qshmqr;*F#byK?hnZycp34xmK17uCH8<Q1$=-

diff --git a/protobuf/gossip.proto b/protobuf/gossip.proto
index 3880cf0..fad0072 100644
--- a/protobuf/gossip.proto
+++ b/protobuf/gossip.proto
@@ -54,4 +54,5 @@ service GossipAPI {
     rpc Discover(ConnectionData) returns (ConnectedNodes) {}
     rpc GossipVrx(VrxMsgGossip) returns (google.protobuf.Empty) {}
     rpc GossipTrx(TrxMsgGossip) returns (google.protobuf.Empty) {}
+    rpc GetVertex(SignedHash) returns (Vertex) {}
 }
diff --git a/src/accountant/accountant.go b/src/accountant/accountant.go
index 8d6a6c4..e4ab5f2 100644
--- a/src/accountant/accountant.go
+++ b/src/accountant/accountant.go
@@ -55,6 +55,7 @@ var (
 	ErrTransferringfundsFailure              = errors.New("transferring spice failure")
 	ErrEntityNotfund                         = errors.New("entity not fund")
 	ErrBreak                                 = errors.New("just break")
+	ErrParentDoesNotExists                   = errors.New("parent doesn't exists")
 )
 
 type signatureVerifier interface {
@@ -556,7 +557,7 @@ func (ab *AccountingBook) addLeafMemorized(ctx context.Context, m memory) error
 				)
 				return ErrLeafRejected
 			}
-			return nil
+			return ErrParentDoesNotExists
 		}
 		existringLeaf, ok := item.(*Vertex)
 		if !ok {
@@ -1115,3 +1116,13 @@ func (ab *AccountingBook) ReadDAGTransactionsByAddress(ctx context.Context, addr
 func (ab *AccountingBook) Address() string {
 	return ab.signer.Address()
 }
+
+// ReadVertex reads vertex by its hash from the vertex if exists or returns error otherwise.
+func (ab *AccountingBook) ReadVertex(ctx context.Context, h [32]byte) (Vertex, error) {
+	v, err := ab.readVertex(h[:])
+	if err != nil {
+		ab.log.Info(fmt.Sprintf("reading vertex hash %v failed, %s", h, err.Error()))
+		return Vertex{}, ErrVertexHashNotfund
+	}
+	return v, nil
+}
diff --git a/src/accountant/replier.go b/src/accountant/replier.go
index 257e737..584913b 100644
--- a/src/accountant/replier.go
+++ b/src/accountant/replier.go
@@ -9,8 +9,8 @@ import (
 )
 
 const (
-	maxArraySize = 250
-	maxRepeats   = 5
+	maxArraySize = 500
+	maxRepeats   = 25
 )
 
 const longevity = time.Minute
diff --git a/src/cmd/wallet/main.go b/src/cmd/wallet/main.go
index 3b2dd25..459cdb7 100644
--- a/src/cmd/wallet/main.go
+++ b/src/cmd/wallet/main.go
@@ -16,6 +16,7 @@ import (
 	"github.com/bartossh/Computantis/src/walletmiddleware"
 	"github.com/pterm/pterm"
 	"github.com/urfave/cli/v2"
+	"golang.org/x/exp/rand"
 )
 
 const (
@@ -25,8 +26,6 @@ const (
 	actionReadAddress
 )
 
-const pauseDuration = time.Second * 2
-
 const usage = `Wallet CLI tool allows to create a new Wallet or act on the local Wallet by using keys from different formats and transforming them between formats.
 Please use with the best security practices. GOBINARY is safer to move between machines as this file format is encrypted with AES key.
 Tool provides Spice and Contract transfer, reading balance, reading contracts, approving and rejecting contracts.`
@@ -305,7 +304,7 @@ func runTransactionOps(cfg fileoperations.Config, nodeURL string) error {
 				continue
 			}
 			spinnerInfo, _ := pterm.DefaultSpinner.Start("Sending transaction ...")
-			time.Sleep(pauseDuration)
+			time.Sleep(getPause())
 			if err := c.ProposeTransaction(ctx, receiver, subject, melange, []byte{}); err != nil {
 				spinnerInfo.Stop()
 				printError(fmt.Errorf("cannot propose transaction due to, %e", err))
@@ -315,7 +314,7 @@ func runTransactionOps(cfg fileoperations.Config, nodeURL string) error {
 			printSuccess()
 		case "Check balance":
 			spinnerInfo, _ := pterm.DefaultSpinner.Start("Checking balance ...")
-			time.Sleep(pauseDuration)
+			time.Sleep(getPause())
 			melange, err := c.ReadBalance(ctx)
 			if err != nil {
 				spinnerInfo.Stop()
@@ -332,7 +331,7 @@ func runTransactionOps(cfg fileoperations.Config, nodeURL string) error {
 			printSuccess()
 		case "Read Transactions":
 			spinnerInfo, _ := pterm.DefaultSpinner.Start("Reading transactions ...")
-			time.Sleep(pauseDuration)
+			time.Sleep(getPause())
 			transactions, err := c.ReadDAGTransactions(ctx)
 			if err != nil {
 				spinnerInfo.Stop()
@@ -453,3 +452,8 @@ func printWarning(warning string) {
 	pterm.Warning.Printf(" %s\n", warning)
 	pterm.Warning.Println("")
 }
+
+func getPause() time.Duration {
+	p := rand.Intn(5)
+	return time.Duration(p) * time.Second
+}
diff --git a/src/gossip/gossip.go b/src/gossip/gossip.go
index 61f7262..8df1eb8 100644
--- a/src/gossip/gossip.go
+++ b/src/gossip/gossip.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"net"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/bartossh/Computantis/src/accountant"
@@ -35,6 +36,7 @@ var (
 	ErrNilTrx                          = errors.New("transaction is nil")
 	ErrNilTrxMsgGossip                 = errors.New("transaction gossip is nil")
 	ErrNilSignedHash                   = errors.New("signed hash is nil")
+	ErrInvalidSignature                = errors.New("invalid signature")
 )
 
 const (
@@ -42,10 +44,11 @@ const (
 )
 
 const (
-	vertexGossipChCapacity = 100
-	trxGossipChCappacity   = 100
-	rejectHashChCapacity   = 80
-	totalRetries           = 10
+	vertexGossipChCapacity         = 100
+	trxGossipChCappacity           = 100
+	rejectHashChCapacity           = 80
+	totalRetries                   = 10
+	maxVertexParentProcessingCount = 250
 )
 
 type nodeData struct {
@@ -81,6 +84,7 @@ type accounter interface {
 	StreamDAG(ctx context.Context) <-chan *accountant.Vertex
 	LoadDag(cancelF context.CancelCauseFunc, cVrx <-chan *accountant.Vertex)
 	DagLoaded() bool
+	ReadVertex(ctx context.Context, h [32]byte) (accountant.Vertex, error)
 }
 
 type piper interface {
@@ -90,17 +94,18 @@ type piper interface {
 
 type gossiper struct {
 	protobufcompiled.UnimplementedGossipAPIServer
-	accounter accounter
-	verifier  signatureVerifier
-	signer    accountant.Signer
-	log       logger.Logger
-	trxCache  providers.AwaitedTrxCacheProviderBalanceCacher
-	flash     providers.FlashbackMemoryHashProviderAddressRemover
-	piper     piper
-	nodes     map[string]nodeData
-	url       string
-	mux       sync.RWMutex
-	timeout   time.Duration
+	accounter             accounter
+	verifier              signatureVerifier
+	signer                accountant.Signer
+	log                   logger.Logger
+	trxCache              providers.AwaitedTrxCacheProviderBalanceCacher
+	flash                 providers.FlashbackMemoryHashProviderAddressRemover
+	piper                 piper
+	nodes                 map[string]nodeData
+	url                   string
+	mux                   sync.RWMutex
+	timeout               time.Duration
+	processingParentCount atomic.Int32
 }
 
 // RunGRPC runs the service application that exposes the GRPC API for gossip protocol.
@@ -117,17 +122,18 @@ func RunGRPC(ctx context.Context, cfg Config, l logger.Logger, t time.Duration,
 	defer cancel()
 
 	g := gossiper{
-		accounter: a,
-		verifier:  v,
-		signer:    s,
-		log:       l,
-		trxCache:  trxCache,
-		flash:     flash,
-		piper:     p,
-		nodes:     make(map[string]nodeData),
-		url:       cfg.URL,
-		mux:       sync.RWMutex{},
-		timeout:   t,
+		accounter:             a,
+		verifier:              v,
+		signer:                s,
+		log:                   l,
+		trxCache:              trxCache,
+		flash:                 flash,
+		piper:                 p,
+		nodes:                 make(map[string]nodeData),
+		url:                   cfg.URL,
+		mux:                   sync.RWMutex{},
+		timeout:               t,
+		processingParentCount: atomic.Int32{},
 	}
 
 	switch cfg.LoadDagURL {
@@ -402,6 +408,19 @@ func (g *gossiper) GossipTrx(ctx context.Context, tg *protobufcompiled.TrxMsgGos
 	return &emptypb.Empty{}, nil
 }
 
+// GetVertex reads vertex from the accountant internal DAG by its hash if exists or returns error otherwise.
+func (g *gossiper) GetVertex(ctx context.Context, in *protobufcompiled.SignedHash) (*protobufcompiled.Vertex, error) {
+	if err := g.verifier.Verify(in.Data, in.Signature, [32]byte(in.Hash), in.Address); err != nil {
+		g.log.Error(fmt.Sprintf("get vertex endpoint failed to verify signature of transaction [ %x ] for address: %s, %s", in.Hash, in.Address, err))
+		return nil, ErrInvalidSignature
+	}
+	vrx, err := g.accounter.ReadVertex(ctx, [32]byte(in.Data))
+	if err != nil {
+		return nil, err
+	}
+	return mapAccountantVertexToProtoVertex(&vrx), nil
+}
+
 func (g *gossiper) updateDag(ctx context.Context, url string) error {
 	nd, err := connectToNode(url)
 	if err != nil {
@@ -611,12 +630,56 @@ func (g *gossiper) updateNodesConnectionsFromGensisNode(ctx context.Context, gen
 	return nil
 }
 
+func (g *gossiper) processLackingParent(ctx context.Context, h [32]byte) {
+	if g.processingParentCount.Load() == maxVertexParentProcessingCount {
+		return
+	}
+	g.processingParentCount.Add(1)
+
+	digest, signature := g.signer.Sign(h[:])
+	for _, nd := range g.nodes {
+
+		vrx, err := nd.client.GetVertex(ctx, &protobufcompiled.SignedHash{
+			Address:   g.signer.Address(),
+			Data:      h[:],
+			Hash:      digest[:],
+			Signature: signature,
+		})
+		if err != nil || vrx == nil {
+			continue
+		}
+		v := mapProtoVertexToAccountantVertex(vrx)
+		if err := g.accounter.AddLeaf(ctx, &v); err != nil {
+			if errors.Is(err, accountant.ErrParentDoesNotExists) {
+				parentHases := [][32]byte{v.LeftParentHash}
+				if v.LeftParentHash != v.RightParentHash {
+					parentHases = append(parentHases, v.RightParentHash)
+				}
+				for _, parentHash := range parentHases {
+					go g.processLackingParent(ctx, parentHash)
+				}
+			}
+		}
+		break
+	}
+	g.processingParentCount.Add(-1)
+}
+
 func (g *gossiper) sendToAccountant(ctx context.Context, vg *protobufcompiled.Vertex) error {
 	if vg.Transaction == nil {
 		return ErrNilTrx
 	}
 	v := mapProtoVertexToAccountantVertex(vg)
 	if err := g.accounter.AddLeaf(ctx, &v); err != nil {
+		if errors.Is(err, accountant.ErrParentDoesNotExists) {
+			parentHases := [][32]byte{v.LeftParentHash}
+			if v.LeftParentHash != v.RightParentHash {
+				parentHases = append(parentHases, v.RightParentHash)
+			}
+			for _, parentHash := range parentHases {
+				go g.processLackingParent(ctx, parentHash)
+			}
+		}
 		return err
 	}
 	return nil
diff --git a/src/protobufcompiled/gossip.pb.go b/src/protobufcompiled/gossip.pb.go
index 704b83e..2a357a0 100644
--- a/src/protobufcompiled/gossip.pb.go
+++ b/src/protobufcompiled/gossip.pb.go
@@ -497,7 +497,7 @@ var file_gossip_proto_rawDesc = []byte{
 	0x6e, 0x73, 0x18, 0x02, 0x20, 0x03, 0x28, 0x0b, 0x32, 0x1b, 0x2e, 0x63, 0x6f, 0x6d, 0x70, 0x75,
 	0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2e, 0x43, 0x6f, 0x6e, 0x6e, 0x65, 0x63, 0x74, 0x69, 0x6f,
 	0x6e, 0x44, 0x61, 0x74, 0x61, 0x52, 0x0b, 0x63, 0x6f, 0x6e, 0x6e, 0x65, 0x63, 0x74, 0x69, 0x6f,
-	0x6e, 0x73, 0x32, 0x91, 0x03, 0x0a, 0x09, 0x47, 0x6f, 0x73, 0x73, 0x69, 0x70, 0x41, 0x50, 0x49,
+	0x6e, 0x73, 0x32, 0xce, 0x03, 0x0a, 0x09, 0x47, 0x6f, 0x73, 0x73, 0x69, 0x70, 0x41, 0x50, 0x49,
 	0x12, 0x39, 0x0a, 0x05, 0x41, 0x6c, 0x69, 0x76, 0x65, 0x12, 0x16, 0x2e, 0x67, 0x6f, 0x6f, 0x67,
 	0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x45, 0x6d, 0x70, 0x74,
 	0x79, 0x1a, 0x16, 0x2e, 0x63, 0x6f, 0x6d, 0x70, 0x75, 0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2e,
@@ -522,11 +522,15 @@ var file_gossip_proto_rawDesc = []byte{
 	0x78, 0x12, 0x19, 0x2e, 0x63, 0x6f, 0x6d, 0x70, 0x75, 0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2e,
 	0x54, 0x72, 0x78, 0x4d, 0x73, 0x67, 0x47, 0x6f, 0x73, 0x73, 0x69, 0x70, 0x1a, 0x16, 0x2e, 0x67,
 	0x6f, 0x6f, 0x67, 0x6c, 0x65, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x2e, 0x45,
-	0x6d, 0x70, 0x74, 0x79, 0x22, 0x00, 0x42, 0x36, 0x5a, 0x34, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62,
-	0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x62, 0x61, 0x72, 0x74, 0x6f, 0x73, 0x73, 0x68, 0x2f, 0x43, 0x6f,
-	0x6d, 0x70, 0x75, 0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2f, 0x73, 0x72, 0x63, 0x2f, 0x70, 0x72,
-	0x6f, 0x74, 0x6f, 0x62, 0x75, 0x66, 0x63, 0x6f, 0x6d, 0x70, 0x69, 0x6c, 0x65, 0x64, 0x62, 0x06,
-	0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x6d, 0x70, 0x74, 0x79, 0x22, 0x00, 0x12, 0x3b, 0x0a, 0x09, 0x47, 0x65, 0x74, 0x56, 0x65, 0x72,
+	0x74, 0x65, 0x78, 0x12, 0x17, 0x2e, 0x63, 0x6f, 0x6d, 0x70, 0x75, 0x74, 0x61, 0x6e, 0x74, 0x69,
+	0x73, 0x2e, 0x53, 0x69, 0x67, 0x6e, 0x65, 0x64, 0x48, 0x61, 0x73, 0x68, 0x1a, 0x13, 0x2e, 0x63,
+	0x6f, 0x6d, 0x70, 0x75, 0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2e, 0x56, 0x65, 0x72, 0x74, 0x65,
+	0x78, 0x22, 0x00, 0x42, 0x36, 0x5a, 0x34, 0x67, 0x69, 0x74, 0x68, 0x75, 0x62, 0x2e, 0x63, 0x6f,
+	0x6d, 0x2f, 0x62, 0x61, 0x72, 0x74, 0x6f, 0x73, 0x73, 0x68, 0x2f, 0x43, 0x6f, 0x6d, 0x70, 0x75,
+	0x74, 0x61, 0x6e, 0x74, 0x69, 0x73, 0x2f, 0x73, 0x72, 0x63, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f,
+	0x62, 0x75, 0x66, 0x63, 0x6f, 0x6d, 0x70, 0x69, 0x6c, 0x65, 0x64, 0x62, 0x06, 0x70, 0x72, 0x6f,
+	0x74, 0x6f, 0x33,
 }
 
 var (
@@ -551,7 +555,8 @@ var file_gossip_proto_goTypes = []interface{}{
 	(*ConnectedNodes)(nil), // 5: computantis.ConnectedNodes
 	(*Transaction)(nil),    // 6: computantis.Transaction
 	(*emptypb.Empty)(nil),  // 7: google.protobuf.Empty
-	(*AliveData)(nil),      // 8: computantis.AliveData
+	(*SignedHash)(nil),     // 8: computantis.SignedHash
+	(*AliveData)(nil),      // 9: computantis.AliveData
 }
 var file_gossip_proto_depIdxs = []int32{
 	6,  // 0: computantis.Vertex.transaction:type_name -> computantis.Transaction
@@ -566,14 +571,16 @@ var file_gossip_proto_depIdxs = []int32{
 	4,  // 9: computantis.GossipAPI.Discover:input_type -> computantis.ConnectionData
 	2,  // 10: computantis.GossipAPI.GossipVrx:input_type -> computantis.VrxMsgGossip
 	3,  // 11: computantis.GossipAPI.GossipTrx:input_type -> computantis.TrxMsgGossip
-	8,  // 12: computantis.GossipAPI.Alive:output_type -> computantis.AliveData
-	0,  // 13: computantis.GossipAPI.LoadDag:output_type -> computantis.Vertex
-	7,  // 14: computantis.GossipAPI.Announce:output_type -> google.protobuf.Empty
-	5,  // 15: computantis.GossipAPI.Discover:output_type -> computantis.ConnectedNodes
-	7,  // 16: computantis.GossipAPI.GossipVrx:output_type -> google.protobuf.Empty
-	7,  // 17: computantis.GossipAPI.GossipTrx:output_type -> google.protobuf.Empty
-	12, // [12:18] is the sub-list for method output_type
-	6,  // [6:12] is the sub-list for method input_type
+	8,  // 12: computantis.GossipAPI.GetVertex:input_type -> computantis.SignedHash
+	9,  // 13: computantis.GossipAPI.Alive:output_type -> computantis.AliveData
+	0,  // 14: computantis.GossipAPI.LoadDag:output_type -> computantis.Vertex
+	7,  // 15: computantis.GossipAPI.Announce:output_type -> google.protobuf.Empty
+	5,  // 16: computantis.GossipAPI.Discover:output_type -> computantis.ConnectedNodes
+	7,  // 17: computantis.GossipAPI.GossipVrx:output_type -> google.protobuf.Empty
+	7,  // 18: computantis.GossipAPI.GossipTrx:output_type -> google.protobuf.Empty
+	0,  // 19: computantis.GossipAPI.GetVertex:output_type -> computantis.Vertex
+	13, // [13:20] is the sub-list for method output_type
+	6,  // [6:13] is the sub-list for method input_type
 	6,  // [6:6] is the sub-list for extension type_name
 	6,  // [6:6] is the sub-list for extension extendee
 	0,  // [0:6] is the sub-list for field type_name
diff --git a/src/protobufcompiled/gossip_grpc.pb.go b/src/protobufcompiled/gossip_grpc.pb.go
index 413a590..5c37c7b 100644
--- a/src/protobufcompiled/gossip_grpc.pb.go
+++ b/src/protobufcompiled/gossip_grpc.pb.go
@@ -29,6 +29,7 @@ type GossipAPIClient interface {
 	Discover(ctx context.Context, in *ConnectionData, opts ...grpc.CallOption) (*ConnectedNodes, error)
 	GossipVrx(ctx context.Context, in *VrxMsgGossip, opts ...grpc.CallOption) (*emptypb.Empty, error)
 	GossipTrx(ctx context.Context, in *TrxMsgGossip, opts ...grpc.CallOption) (*emptypb.Empty, error)
+	GetVertex(ctx context.Context, in *SignedHash, opts ...grpc.CallOption) (*Vertex, error)
 }
 
 type gossipAPIClient struct {
@@ -116,6 +117,15 @@ func (c *gossipAPIClient) GossipTrx(ctx context.Context, in *TrxMsgGossip, opts
 	return out, nil
 }
 
+func (c *gossipAPIClient) GetVertex(ctx context.Context, in *SignedHash, opts ...grpc.CallOption) (*Vertex, error) {
+	out := new(Vertex)
+	err := c.cc.Invoke(ctx, "/computantis.GossipAPI/GetVertex", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // GossipAPIServer is the server API for GossipAPI service.
 // All implementations must embed UnimplementedGossipAPIServer
 // for forward compatibility
@@ -126,6 +136,7 @@ type GossipAPIServer interface {
 	Discover(context.Context, *ConnectionData) (*ConnectedNodes, error)
 	GossipVrx(context.Context, *VrxMsgGossip) (*emptypb.Empty, error)
 	GossipTrx(context.Context, *TrxMsgGossip) (*emptypb.Empty, error)
+	GetVertex(context.Context, *SignedHash) (*Vertex, error)
 	mustEmbedUnimplementedGossipAPIServer()
 }
 
@@ -151,6 +162,9 @@ func (UnimplementedGossipAPIServer) GossipVrx(context.Context, *VrxMsgGossip) (*
 func (UnimplementedGossipAPIServer) GossipTrx(context.Context, *TrxMsgGossip) (*emptypb.Empty, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method GossipTrx not implemented")
 }
+func (UnimplementedGossipAPIServer) GetVertex(context.Context, *SignedHash) (*Vertex, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method GetVertex not implemented")
+}
 func (UnimplementedGossipAPIServer) mustEmbedUnimplementedGossipAPIServer() {}
 
 // UnsafeGossipAPIServer may be embedded to opt out of forward compatibility for this service.
@@ -275,6 +289,24 @@ func _GossipAPI_GossipTrx_Handler(srv interface{}, ctx context.Context, dec func
 	return interceptor(ctx, in, info, handler)
 }
 
+func _GossipAPI_GetVertex_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(SignedHash)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(GossipAPIServer).GetVertex(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/computantis.GossipAPI/GetVertex",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(GossipAPIServer).GetVertex(ctx, req.(*SignedHash))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 // GossipAPI_ServiceDesc is the grpc.ServiceDesc for GossipAPI service.
 // It's only intended for direct use with grpc.RegisterService,
 // and not to be introspected or modified (even as a copy)
@@ -302,6 +334,10 @@ var GossipAPI_ServiceDesc = grpc.ServiceDesc{
 			MethodName: "GossipTrx",
 			Handler:    _GossipAPI_GossipTrx_Handler,
 		},
+		{
+			MethodName: "GetVertex",
+			Handler:    _GossipAPI_GetVertex_Handler,
+		},
 	},
 	Streams: []grpc.StreamDesc{
 		{
diff --git a/src/spice/spice.go b/src/spice/spice.go
index ecfe4cd..0e25866 100644
--- a/src/spice/spice.go
+++ b/src/spice/spice.go
@@ -51,16 +51,6 @@ func convertFloatToInt(d float64) (int, int) {
 	return intPart, fractionalPart
 }
 
-func GetSientific(v uint64) string {
-	var zeros int
-	for v%10 == 0 {
-		zeros++
-		v /= 10
-	}
-
-	return fmt.Sprintf("%v*10^%v", v, zeros)
-}
-
 // Melange is an asset that is digitally transferable between two wallets.
 type Melange struct {
 	Currency              uint64 `yaml:"currency"               msgpack:"currency"`
diff --git a/src/spice/spice_test.go b/src/spice/spice_test.go
index 287055a..9e94313 100644
--- a/src/spice/spice_test.go
+++ b/src/spice/spice_test.go
@@ -159,28 +159,6 @@ func BenchmarkMelangeTransfer(b *testing.B) {
 	}
 }
 
-func TestPrintGetScientific(t *testing.T) {
-	cases := []uint64{
-		10,
-		100,
-		1000,
-		10000,
-		100000,
-		1000000,
-		1100000,
-		1110000,
-		1111000,
-		1111100,
-		1111110,
-	}
-	for _, c := range cases {
-		t.Run(fmt.Sprintf("get scientific test case %v", c), func(t *testing.T) {
-			s := GetSientific(c)
-			fmt.Printf("%s\n", s)
-		})
-	}
-}
-
 func TestFromFloat(t *testing.T) {
 	cases := []struct {
 		expected string