dagchain

README

dagchain

A modern peer to peer(P2P) network library over TCP written in Go, there is no third party deps in dagchain,so it's extremely easy to use in your project.

We have implemented intelligent node discovery、data routing with DAG like algorithm, avoid data redundancy and connection redundancy.

so it's very suitable for simple blockchain project and teaching case.

Notice! This project is still under heavy development, for now,you can use it in simple blockchain or demos.

Features

• Pure Go and Easy using
• Based on TCP/TLS
• Abstract Transport: Non-IP network
• Encryption(todo)
• NAT Tranversal(todo)
• Peer Discovery(to be optimized)
• Resource Discovery(todo)
• Intelligent message routing(to be optimized)
• Cluster Partition avoidance(to be optimized)
• Messaging by Multicast etc (todo)
• Detail docs and code comments(Todo docs)

How to use

demo code

package main

import (
	"flag"
	"fmt"
	"time"

	"github.com/465583030/dagchain"
)

var laddr = flag.String("l", "", "")
var saddr = flag.String("s", "", "")
var messaging = flag.Bool("m", false, "")
var id = flag.String("i", "", "")

func main() {
	flag.Parse()

	send := make(chan interface{}, 1)
	recv := make(chan interface{}, 1)
	// start the p2p node
	go func() {
		err := dagchain.StartNode(*laddr, *saddr, send, recv)
		if err != nil {
			panic("node start panic:" + err.Error())
		}
	}()

	// wait 1 second for p2p node started
	time.Sleep(1 * time.Second)

	// query 10 nodes address from p2p network
	addrs := dagchain.QueryNodes(10)

	// excute some actions with the nodes address,like downloads blockchain from these nodes
	// all depends on yourself
	fmt.Println("query nodes:", addrs)
    
	// send message to all the other nodes
	if *messaging {
		data := "hello-" + *id
		go func() {
			for {
				send <- data
				time.Sleep(5 * time.Second)
				fmt.Println("send message：", data)
			}
		}()
	}

	// receive message from other nodes
	for {
		select {
		case r := <-recv:
			res := r.(*dagchain.Request)
			fmt.Printf("receive message: %v from other node: \"%s\" \n", res.Data, res.From)
		}
	}

}

terminal

open the first terminal

go run main.go -l localhost:2000 -m -i 1

open the second terminal

go run main.go -l localhost:2001 -s localhost:2000 -m -i 2

the third

go run main.go -l localhost:2002 -s localhost:2001 -m -i 3

the fourth

go run main.go -l localhost:2003 -s localhost:2002 -m -i 4

the fifth

go run main.go -l localhost:2004 -s localhost:2002 -m -i 5

some explanation

• -l means the node will listen on this address
• -s means the node will first connect to this seed address
• -m means the node will send message to the p2p network
• -i 5 just give the -m message a little variety

You can start as many nodes as you like, and you can kill any node as you like,

Documentation

Index

• Constants
• func QueryNodes(max int) []string
• func StartNode(laddr, saddr string, send, recv chan interface{}) error
• type Node
• type Packet
• type Request
• type Seed

Constants

const (
	NormalRequest         = 0 // outer application's data
	NormalRequestReceived = 1 // ack
	ServerPing            = 2 // ping to the seed
	ServerPong            = 3 // pong to the ping
	BackupSeeds           = 4 // return the backup seeds
	SyncBackupSeeds       = 5 // query for the backup seeds
)

Functions

func QueryNodes

func QueryNodes(max int) []string

QueryNodes, just query nodes info from p2p, the actions followed has noting to do with p2p

func StartNode

func StartNode(laddr, saddr string, send, recv chan interface{}) error

laddr: our node's listen addr saddr: the source seed addr send: outer application pushes messages to this channel recv: outer application receives messages from this channel

Types

type Node

type Node struct {
	// contains filtered or unexported fields
}

Node is the local server

type Packet

type Packet struct {
	Addr string
	// contains filtered or unexported fields
}

type Request

type Request struct {
	ID      int64
	Command int
	Data    interface{}
	From    string
}

Request 节点之间交换的数据结构

type Seed

type Seed struct {
	// contains filtered or unexported fields
}

Seed structure