try to sent len of peer blockchain

chain/chain.go

@@ -226,6 +226,7 @@ func (chain *Blockchain) AddBlock(block Block) {
 	if len(chain.Blocks) != 0 {
 		block.PreviousHash = chain.Blocks[len(chain.Blocks)-1].Hash
 	}
+	block.Hash = block.CalculateHash()
 	chain.Blocks = append(chain.Blocks, block)
 }
 

cmd/blockchain/main.go

@@ -112,8 +112,10 @@ func main() {
 					Transactions: nil,
 					Timestamp:    time.Now().Unix(),
 					Capacity:     5,
-					PreviousHash: "previousHash",
+					Nonce:        59349,
+					PreviousHash: blockchain.Blocks[len(blockchain.Blocks)-1].Hash,
 				}
+				block.Hash = block.CalculateHash()
 				node.BroadcastBlock(block)
 			default:
 				fmt.Println("Unknown message type")

p2p/cronjob.go

@@ -0,0 +1,41 @@
+package p2p
+
+import (
+	"blockchain/chain"
+	"context"
+	"fmt"
+	"net"
+	"time"
+)
+
+func task(ctx context.Context, node *Node, conn net.Conn, blockchain *chain.Blockchain) {
+	for {
+		select {
+		// проверяем не завершён ли ещё контекст и выходим, если завершён
+		case <-ctx.Done():
+			return
+
+		default:
+			// запросить длину блокчейна
+			_, err := conn.Write([]byte("Give me length of your blockchain!\n"))
+			if err != nil {
+				fmt.Println("Error writing to connection:", err)
+				node.RemoveConnection(conn.RemoteAddr().String())
+				return
+			}
+		}
+		// делаем паузу перед следующей итерацией
+		time.Sleep(time.Minute)
+	}
+}
+
+func cronjob(node *Node, conn net.Conn, blockchain *chain.Blockchain) {
+	// create a scheduler
+	// создаём контекст с функцией завершения
+	ctx, cancel := context.WithCancel(context.Background())
+	go task(ctx, node, conn, blockchain)
+	// делаем паузу, чтобы дать горутине поработать
+	time.Sleep(10 * time.Minute)
+	// завершаем контекст, чтобы завершить горутину
+	cancel()
+}

p2p/p2p.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"os"
+	"strconv"
 	"strings"
 	"sync"
 )
@@ -51,6 +52,7 @@ func (node *Node) StartServer(blockchain *chain.Blockchain) {
 			continue
 		}
 		go node.HandleConnection(conn, blockchain)
+		go cronjob(node, conn, blockchain)
 	}
 }
 
@@ -157,11 +159,14 @@ func (node *Node) HandleConnection(conn net.Conn, blockchain *chain.Blockchain)
 			return
 		}
 		fmt.Println("Received Message:", message)
-
-		err = ProcessMessage(message, blockchain)
-		if err != nil {
-			fmt.Println("Error processing message:", err)
-			return
+		if strings.HasPrefix(message, "Length of Blockchain") {
+			node.ReadLenBlockchain(peerAddress, message)
+		} else {
+			err = ProcessMessage(message, blockchain)
+			if err != nil {
+				fmt.Println("Error processing message:", err)
+				return
+			}
 		}
 	}
 }
@@ -218,6 +223,25 @@ func (node *Node) RemoveConnection(peerAddress string) {
 	}
 }
 
+func (node *Node) SentLenBlockchain(conn net.Conn, blockchain *chain.Blockchain) {
+	// Отправлять только длину валидного блокчейна
+	if !blockchain.IsValid() {
+		fmt.Println("Can't send Length, Blockchain is invalid")
+		return
+	}
+
+	num := len(blockchain.Blocks)
+	message := strconv.Itoa(num)
+	_, err := conn.Write([]byte("Length of Blockchain:" + message + "\n"))
+
+	if err != nil {
+		fmt.Println("Error writing to connection:", err)
+		node.RemoveConnection(conn.RemoteAddr().String())
+		return
+	}
+	fmt.Println("Sent Length of my Blockchain:", len(blockchain.Blocks))
+}
+
 func (node *Node) ReadData(conn net.Conn, blockchain *chain.Blockchain) {
 	reader := bufio.NewReader(conn)
 	for {
@@ -228,10 +252,15 @@ func (node *Node) ReadData(conn net.Conn, blockchain *chain.Blockchain) {
 			return
 		}
 		fmt.Println("Received in ReadData:", message)
-		err = ProcessMessage(message, blockchain)
-		if err != nil {
-			fmt.Println("Error processing message:", err)
-			return
+
+		if strings.HasPrefix(message, "Give me length of your blockchain") {
+			node.SentLenBlockchain(conn, blockchain)
+		} else {
+			err = ProcessMessage(message, blockchain)
+			if err != nil {
+				fmt.Println("Error processing message:", err)
+				return
+			}
 		}
 	}
 }
@@ -271,3 +300,14 @@ func (node *Node) BroadcastBlock(block chain.Block) {
 	}
 	node.BroadcastMessage(string(blockJson))
 }
+
+func (node *Node) ReadLenBlockchain(address string, message string) {
+	// Get len of blockchain
+	message = strings.Split(message, ":")[1]
+	otherLenBlockchain, _ := strconv.Atoi(strings.TrimSpace(message))
+	fmt.Printf(
+		"Received len of blockhain: %d, peer address: %s\n",
+		otherLenBlockchain,
+		address,
+	)
+}