Protocol leg work

go.mod

@@ -0,0 +1,62 @@
+module striveworks.us/stampede
+
+go 1.15
+
+require (
+	9fans.net/go v0.0.2 // indirect
+	github.com/Djarvur/go-err113 v0.1.0 // indirect
+	github.com/alecthomas/gometalinter v3.0.0+incompatible // indirect
+	github.com/alecthomas/units v0.0.0-20201120081800-1786d5ef83d4 // indirect
+	github.com/ashanbrown/forbidigo v1.1.0 // indirect
+	github.com/esimonov/ifshort v1.0.1 // indirect
+	github.com/fatih/gomodifytags v1.13.0 // indirect
+	github.com/go-critic/go-critic v0.5.4 // indirect
+	github.com/gofrs/uuid v4.0.0+incompatible
+	github.com/golangci/golangci-lint v1.36.0 // indirect
+	github.com/golangci/misspell v0.3.5 // indirect
+	github.com/golangci/revgrep v0.0.0-20180812185044-276a5c0a1039 // indirect
+	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
+	github.com/gostaticanalysis/analysisutil v0.6.1 // indirect
+	github.com/jingyugao/rowserrcheck v0.0.0-20210130005344-c6a0c12dd98d // indirect
+	github.com/jirfag/go-printf-func-name v0.0.0-20200119135958-7558a9eaa5af // indirect
+	github.com/magiconair/properties v1.8.4 // indirect
+	github.com/matoous/godox v0.0.0-20200801072554-4fb83dc2941e // indirect
+	github.com/mattn/go-runewidth v0.0.10 // indirect
+	github.com/mbilski/exhaustivestruct v1.2.0 // indirect
+	github.com/mdempsky/gocode v0.0.0-20200405233807-4acdcbdea79d // indirect
+	github.com/mgechev/revive v1.0.3 // indirect
+	github.com/mitchellh/mapstructure v1.4.1 // indirect
+	github.com/nicksnyder/go-i18n v1.10.1 // indirect
+	github.com/opennota/check v0.0.0-20180911053232-0c771f5545ff // indirect
+	github.com/pelletier/go-toml v1.8.1 // indirect
+	github.com/quasilyte/regex/syntax v0.0.0-20200805063351-8f842688393c // indirect
+	github.com/ramya-rao-a/go-outline v0.0.0-20200117021646-2a048b4510eb // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/rogpeppe/godef v1.1.2 // indirect
+	github.com/sirupsen/logrus v1.7.0
+	github.com/spf13/afero v1.5.1 // indirect
+	github.com/spf13/cast v1.3.1 // indirect
+	github.com/spf13/jwalterweatherman v1.1.0 // indirect
+	github.com/sqs/goreturns v0.0.0-20181028201513-538ac6014518 // indirect
+	github.com/stretchr/objx v0.3.0 // indirect
+	github.com/stripe/safesql v0.2.0 // indirect
+	github.com/tdakkota/asciicheck v0.0.0-20200416200610-e657995f937b // indirect
+	github.com/tetafro/godot v1.4.4 // indirect
+	github.com/timakin/bodyclose v0.0.0-20200424151742-cb6215831a94 // indirect
+	github.com/tomarrell/wrapcheck v0.0.0-20201130113247-1683564d9756 // indirect
+	github.com/tpng/gopkgs v0.0.0-20180428091733-81e90e22e204 // indirect
+	github.com/tsenart/deadcode v0.0.0-20160724212837-210d2dc333e9 // indirect
+	github.com/zmb3/goaddimport v0.0.0-20170810013102-4ab94a07ab86 // indirect
+	github.com/zmb3/gogetdoc v0.0.0-20190228002656-b37376c5da6a // indirect
+	golang.org/x/lint v0.0.0-20201208152925-83fdc39ff7b5 // indirect
+	golang.org/x/mod v0.4.1 // indirect
+	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c // indirect
+	golang.org/x/text v0.3.5 // indirect
+	golang.org/x/tools v0.1.0 // indirect
+	gopkg.in/alecthomas/kingpin.v3-unstable v3.0.0-20191105091915-95d230a53780 // indirect
+	gopkg.in/ini.v1 v1.62.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+	honnef.co/go/tools v0.1.1 // indirect
+	mvdan.cc/unparam v0.0.0-20210104141923-aac4ce9116a7 // indirect
+)

main.go

@@ -1,9 +1,16 @@
 package main
 
 import (
-  "striveworks.us/stampede/pkg/listen"
+	"striveworks.us/stampede/pkg"
+)
+
+const (
+	sendAddress   = "127.0.0.1:9999"
+	listenAddress = ":9999"
 )
 
 func main() {
-  Listen()
+	node := pkg.New(&pkg.NodeConfig{IsLeader: false})
+	node.Start()
+
 }

pkg/leader.go

@@ -0,0 +1,40 @@
+package pkg
+
+import (
+	"net"
+	"time"
+)
+
+type LeaderMessage struct {
+	Type      string    `json:"type"`
+	Timestamp time.Time `json:"time"`
+	Message   string    `json:"message"`
+	Node      Node      `json:"node"`
+}
+
+type LeaderResponse struct {
+	LeaderMessage LeaderMessage  `json:"leader"`
+	Address       net.Addr       `json:"address"`
+	Connection    net.PacketConn `json:"connection"`
+}
+
+func BecomeLeader(node Node) {
+	m := LeaderMessage{Type: "Election", Message: "Win", Timestamp: time.Now(), Node: node}
+	Broadcast(m)
+}
+
+func LeaderAsk(node Node) {
+	m := LeaderMessage{Type: "Election", Message: "Vote", Timestamp: time.Now(), Node: node}
+	Broadcast(m)
+}
+
+func DenyElection(node Node) {
+	m := LeaderMessage{Type: "Election", Message: "Denied", Timestamp: time.Now(), Node: node}
+	Broadcast(m)
+
+}
+
+func HeartBeat(node Node) {
+	m := LeaderMessage{Type: "Heartbeat", Message: "Alive", Timestamp: time.Now(), Node: node}
+	Broadcast(m)
+}

pkg/node.go

@@ -0,0 +1,114 @@
+package pkg
+
+import (
+	"time"
+
+	"github.com/gofrs/uuid"
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	waitInterval     = 3
+	electionInterval = 3
+)
+
+type Node struct {
+	UUID         string    `json:"uuid"`
+	IsLeader     bool      `json:"isleader"`
+	Voting       bool      `json:"voting"`
+	ElectionTime time.Time `json:"election"`
+}
+
+//NodeConfig ...
+type NodeConfig struct {
+	IsLeader bool
+}
+
+//New ...
+func New(cfg *NodeConfig) Node {
+
+	return Node{
+		UUID:     generateUUID().String(),
+		IsLeader: cfg.IsLeader,
+	}
+}
+
+func (node Node) Start() error {
+	listener := make(chan LeaderResponse)
+	//Use a nodePool map so lookup times are O(1)
+	nodePool := make(map[string]Node)
+	electionDenials := 0
+	startTime := time.Now()
+
+	go Listen(listener)
+
+	for {
+		// Create non-blocking channel to listen for UDP messages
+		select {
+		case response := <-listener:
+			log.Info(response)
+			//Only care about messages that aren't from myself
+			if response.LeaderMessage.Node.UUID != node.UUID {
+
+				//Add other nodes to NodePool if they do not exist
+				if _, ok := nodePool[node.UUID]; ok {
+				} else {
+					nodePool[node.UUID] = node
+				}
+
+				//Increment Election denial
+				if response.LeaderMessage.Type == "Election" && response.LeaderMessage.Message == "Denied" {
+					electionDenials++
+				}
+
+				//Reject other leader elections if I am the leader
+				if node.IsLeader && response.LeaderMessage.Type == "Election" && response.LeaderMessage.Message == "Vote" {
+					DenyElection(node)
+				}
+
+				//TODO
+				//If I get heartbeats from other nodes and I am the leader, send back shared key
+
+			}
+		default:
+		}
+
+		waitElapsed := time.Since(startTime).Seconds()
+		electionElapsed := time.Since(node.ElectionTime).Seconds()
+
+		//If I am voting and have not heard any denies in election interval, become Leader
+		if !node.IsLeader && node.Voting && electionElapsed > electionInterval && electionDenials == 0 {
+			BecomeLeader(node)
+			node.IsLeader = true
+			log.Info("Have heard ", electionDenials, " denials")
+			log.Info("Assuming leader role")
+		}
+
+		//If I haven't gotten any heartbeats from other nodes in specified interval and I haven't already voted, make leader election
+		if !node.IsLeader && waitElapsed > waitInterval && !node.Voting && len(nodePool) == 0 {
+			node.Voting = true
+			node.ElectionTime = time.Now()
+			LeaderAsk(node)
+			log.Info("Sending election request")
+		}
+
+		//TODO
+		//Case when multiple nodes are competing for leader role
+		HeartBeat(node)
+		time.Sleep(1 * time.Second)
+	}
+}
+
+var nsUUID = uuid.Must(uuid.FromString("34b13033-50e7-4083-97f5-d389cf3a1c0e"))
+
+func generateUUID() uuid.UUID {
+	id, err := uuid.NewV1()
+	if err != nil {
+		id, err = uuid.NewV4()
+		if err != nil {
+			return uuid.NewV5(nsUUID, time.Now().String())
+		}
+	}
+
+	return id
+}

pkg/udp.go

@@ -0,0 +1,59 @@
+package pkg
+
+import (
+	"encoding/json"
+	"log"
+	"net"
+)
+
+const (
+	sendAddress   = "127.0.0.1:9999"
+	listenAddress = ":9999"
+)
+
+//Broadcast ..
+func Broadcast(leaderMessage LeaderMessage) {
+	addr, err := net.ResolveUDPAddr("udp4", sendAddress)
+	if err != nil {
+		panic(err)
+	}
+
+	conn, err := net.DialUDP("udp4", nil, addr)
+
+	var jsonData []byte
+	jsonData, err = json.Marshal(leaderMessage)
+	if err != nil {
+		log.Println(err)
+	}
+	_, err = conn.Write(jsonData)
+	if err != nil {
+		panic(err)
+	}
+
+}
+
+//Listen ..
+func Listen(c chan LeaderResponse) {
+	defer close(c)
+	conn, err := net.ListenPacket("udp4", listenAddress)
+	if err != nil {
+		panic(err)
+	}
+	defer conn.Close()
+
+	for {
+		buf := make([]byte, 1024)
+		n, addr, err := conn.ReadFrom(buf)
+		if err != nil {
+			panic(err)
+		}
+		data := buf[:n]
+		var response LeaderMessage
+		err = json.Unmarshal(data, &response)
+
+		result := LeaderResponse{LeaderMessage: response, Address: addr, Connection: conn}
+
+		c <- result
+
+	}
+}