gee-rpc: doc add day5 day6 day7

gee-rpc/day6-load-balance/main/main.go

@@ -46,7 +46,7 @@ func foo(xc *xclient.XClient, ctx context.Context, typ, serviceMethod string, ar
 	if err != nil {
 		log.Printf("%s %s error: %v", typ, serviceMethod, err)
 	} else {
-		log.Printf("%s Foo.Sum success: %d + %d = %d", typ, args.Num1, args.Num2, reply)
+		log.Printf("%s %s success: %d + %d = %d", typ, serviceMethod, args.Num1, args.Num2, reply)
 	}
 }
 
@@ -69,6 +69,7 @@ func call(addr1, addr2 string) {
 func broadcast(addr1, addr2 string) {
 	d := xclient.NewMultiServerDiscovery([]string{"tcp@" + addr1, "tcp@" + addr2})
 	xc := xclient.NewXClient(d, xclient.RandomSelect, nil)
+	defer func() { _ = xc.Close() }()
 	var wg sync.WaitGroup
 	for i := 0; i < 5; i++ {
 		wg.Add(1)

gee-rpc/day6-load-balance/xclient/discovery.go

@@ -2,6 +2,7 @@ package xclient
 
 import (
 	"errors"
+	"math"
 	"math/rand"
 	"sync"
 	"time"
@@ -49,15 +50,16 @@ func (d *MultiServersDiscovery) Update(servers []string) error {
 func (d *MultiServersDiscovery) Get(mode SelectMode) (string, error) {
 	d.mu.Lock()
 	defer d.mu.Unlock()
-	if len(d.servers) == 0 {
+	n := len(d.servers)
+	if n == 0 {
 		return "", errors.New("rpc discovery: no available servers")
 	}
 	switch mode {
 	case RandomSelect:
-		return d.servers[d.r.Intn(len(d.servers))], nil
+		return d.servers[d.r.Intn(n)], nil
 	case RoundRobinSelect:
-		s := d.servers[d.index]
-		d.index = (d.index + 1) % len(d.servers)
+		s := d.servers[d.index%n] // servers could be updated, so mode n to ensure safety
+		d.index = (d.index + 1) % n
 		return s, nil
 	default:
 		return "", errors.New("rpc discovery: not supported select mode")
@@ -76,8 +78,10 @@ func (d *MultiServersDiscovery) GetAll() ([]string, error) {
 
 // NewMultiServerDiscovery creates a MultiServersDiscovery instance
 func NewMultiServerDiscovery(servers []string) *MultiServersDiscovery {
-	return &MultiServersDiscovery{
+	d := &MultiServersDiscovery{
 		servers: servers,
 		r:       rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
+	d.index = d.r.Intn(math.MaxInt32 - 1)
+	return d
 }

gee-rpc/day7-registry/main/main.go

@@ -3,7 +3,7 @@ package main
 import (
 	"context"
 	"geerpc"
-	registy "geerpc/registry"
+	"geerpc/registry"
 	"geerpc/xclient"
 	"log"
 	"net"
@@ -29,17 +29,17 @@ func (f Foo) Sleep(args Args, reply *int) error {
 
 func startRegistry(wg *sync.WaitGroup) {
 	l, _ := net.Listen("tcp", ":9999")
-	registy.HandleHTTP()
+	registry.HandleHTTP()
 	wg.Done()
 	_ = http.Serve(l, nil)
 }
 
-func startServer(registry string, wg *sync.WaitGroup) {
+func startServer(registryAddr string, wg *sync.WaitGroup) {
 	var foo Foo
 	l, _ := net.Listen("tcp", ":0")
 	server := geerpc.NewServer()
 	_ = server.Register(&foo)
-	registy.Heartbeat(registry, "tcp@"+l.Addr().String(), 0)
+	registry.Heartbeat(registryAddr, "tcp@"+l.Addr().String(), 0)
 	wg.Done()
 	server.Accept(l)
 }
@@ -56,7 +56,7 @@ func foo(xc *xclient.XClient, ctx context.Context, typ, serviceMethod string, ar
 	if err != nil {
 		log.Printf("%s %s error: %v", typ, serviceMethod, err)
 	} else {
-		log.Printf("%s Foo.Sum success: %d + %d = %d", typ, args.Num1, args.Num2, reply)
+		log.Printf("%s %s success: %d + %d = %d", typ, serviceMethod, args.Num1, args.Num2, reply)
 	}
 }
 
@@ -79,6 +79,7 @@ func call(registry string) {
 func broadcast(registry string) {
 	d := xclient.NewGeeRegistryDiscovery(registry, 0)
 	xc := xclient.NewXClient(d, xclient.RandomSelect, nil)
+	defer func() { _ = xc.Close() }()
 	var wg sync.WaitGroup
 	for i := 0; i < 5; i++ {
 		wg.Add(1)

gee-rpc/day7-registry/registry/registry.go

@@ -1,4 +1,4 @@
-package registy
+package registry
 
 import (
 	"log"
@@ -9,10 +9,10 @@ import (
 	"time"
 )
 
-// Registry is a simple register center, provide following functions.
+// GeeRegistry is a simple register center, provide following functions.
 // add a server and receive heartbeat to keep it alive.
 // returns all alive servers and delete dead servers sync simultaneously.
-type Registry struct {
+type GeeRegistry struct {
 	timeout time.Duration
 	mu      sync.Mutex // protect following
 	servers map[string]*ServerItem
@@ -23,17 +23,22 @@ type ServerItem struct {
 	start time.Time
 }
 
+const (
+	defaultPath    = "/_geerpc_/registry"
+	defaultTimeout = time.Minute * 5
+)
+
 // New create a registry instance with timeout setting
-func New(timeout time.Duration) *Registry {
-	return &Registry{
+func New(timeout time.Duration) *GeeRegistry {
+	return &GeeRegistry{
 		servers: make(map[string]*ServerItem),
 		timeout: timeout,
 	}
 }
 
-var DefaultRegister = New(defaultTimeout)
+var DefaultGeeRegister = New(defaultTimeout)
 
-func (r *Registry) putServer(addr string) {
+func (r *GeeRegistry) putServer(addr string) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	s := r.servers[addr]
@@ -44,7 +49,7 @@ func (r *Registry) putServer(addr string) {
 	}
 }
 
-func (r *Registry) aliveServers() []string {
+func (r *GeeRegistry) aliveServers() []string {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	var alive []string
@@ -59,13 +64,8 @@ func (r *Registry) aliveServers() []string {
 	return alive
 }
 
-const (
-	defaultPath    = "/_geerpc_/registry"
-	defaultTimeout = time.Minute * 5
-)
-
 // Runs at /_geerpc_/registry
-func (r *Registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+func (r *GeeRegistry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	switch req.Method {
 	case "GET":
 		// keep it simple, server is in req.Header
@@ -83,14 +83,14 @@ func (r *Registry) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
-// HandleHTTP registers an HTTP handler for Registry messages on registryPath
-func (r *Registry) HandleHTTP(registryPath string) {
+// HandleHTTP registers an HTTP handler for GeeRegistry messages on registryPath
+func (r *GeeRegistry) HandleHTTP(registryPath string) {
 	http.Handle(registryPath, r)
 	log.Println("rpc registry path:", registryPath)
 }
 
 func HandleHTTP() {
-	DefaultRegister.HandleHTTP(defaultPath)
+	DefaultGeeRegister.HandleHTTP(defaultPath)
 }
 
 // Heartbeat send a heartbeat message every once in a while
@@ -113,7 +113,7 @@ func Heartbeat(registry, addr string, duration time.Duration) {
 }
 
 func sendHeartbeat(registry, addr string) error {
-	log.Println(addr, "send heart beat to registry")
+	log.Println(addr, "send heart beat to registry", registry)
 	httpClient := &http.Client{}
 	req, _ := http.NewRequest("POST", registry, nil)
 	req.Header.Set("X-Geerpc-Server", addr)

gee-rpc/day7-registry/xclient/discovery.go

@@ -2,6 +2,7 @@ package xclient
 
 import (
 	"errors"
+	"math"
 	"math/rand"
 	"sync"
 	"time"
@@ -77,8 +78,10 @@ func (d *MultiServersDiscovery) GetAll() ([]string, error) {
 
 // NewMultiServerDiscovery creates a MultiServersDiscovery instance
 func NewMultiServerDiscovery(servers []string) *MultiServersDiscovery {
-	return &MultiServersDiscovery{
+	d := &MultiServersDiscovery{
 		servers: servers,
 		r:       rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
+	d.index = d.r.Intn(math.MaxInt32 - 1)
+	return d
 }

gee-rpc/doc/geerpc-day1.md

@@ -19,7 +19,7 @@ github: https://github.com/geektutu/7days-golang
 
 ![golang RPC framework](geerpc/geerpc.jpg)
 
-本文是[7天用Go从零实现RPC框架GeeRPC]的第一篇。
+本文是[7天用Go从零实现RPC框架GeeRPC](https://geektutu.com/post/geerpc.html)的第一篇。
 
 - 使用 `encoding/gob` 实现消息的编解码(序列化与反序列化)
 - 实现一个简易的服务端，仅接受消息，不处理，代码约 200 行
@@ -54,7 +54,7 @@ type Header struct {
 - Error 是错误信息，客户端置为空，服务端如果如果发生错误，将错误信息置于 Error 中。
 
 
-我们将和消息编解码相关的代码都防到 codec 目录中。
+我们将和消息编解码相关的代码都防到 codec 子目录中，在此之前，还需要在根目录下使用 `go mod init geerpc` 初始化项目，方便后续子 package 之间的引用。
 
 进一步，抽象出对消息体进行编解码的接口 Codec，抽象出接口是为了实现不同的 Codec 实例：
 

gee-rpc/doc/geerpc-day2.md

@@ -19,7 +19,7 @@ github: https://github.com/geektutu/7days-golang
 
 ![golang RPC framework](geerpc/geerpc.jpg)
 
-本文是[7天用Go从零实现RPC框架GeeRPC]的第二篇。
+本文是[7天用Go从零实现RPC框架GeeRPC](https://geektutu.com/post/geerpc.html)的第二篇。
 
 - 实现一个支持异步和并发的高性能客户端，代码约 250 行
 

gee-rpc/doc/geerpc-day3.md

@@ -18,7 +18,7 @@ github: https://github.com/geektutu/7days-golang
 
 ![golang RPC framework](geerpc/geerpc.jpg)
 
-本文是[7天用Go从零实现RPC框架GeeRPC]的第三篇。
+本文是[7天用Go从零实现RPC框架GeeRPC](https://geektutu.com/post/geerpc.html)的第三篇。
 
 - 通过反射实现服务注册功能
 - 在服务端实现服务调用，代码约 150 行

gee-rpc/doc/geerpc-day4.md

@@ -17,7 +17,7 @@ github: https://github.com/geektutu/7days-golang
 
 ![golang RPC framework](geerpc/geerpc.jpg)
 
-本文是[7天用Go从零实现RPC框架GeeRPC]的第四篇。
+本文是[7天用Go从零实现RPC框架GeeRPC](https://geektutu.com/post/geerpc.html)的第四篇。
 
 - 增加连接超时的处理机制
 - 增加服务端处理超时的处理机制，代码约 100 行