From 3c5bfd8e6b4f1e159c775603ce7be9565d091a81 Mon Sep 17 00:00:00 2001
From: han-joker <hanJoker@mail.com>
Date: Thu, 2 Mar 2023 18:13:21 +0800
Subject: [PATCH] goroutine and demo

---
 channel.go         |  28 ++++++
 channel_test.go    |   4 +
 context.go         |   2 +-
 context_test.go    |   4 +-
 demoQuickSort.go   |  78 ++++++++++++++++
 demoWalkDir.go     | 109 ++++++++++++++++++++++
 demo_test.go       |  23 +++++
 go.mod             |   2 +
 go.sum             |  15 ++++
 goroutine.go       | 219 +++++++++++++++++++++++++++++++++++++++++++++
 goroutine_test.go  |  27 ++++++
 selectStmt.go      |  33 +++++++
 selectStmt_test.go |   4 +
 test/test.go       |  24 +++++
 14 files changed, 569 insertions(+), 3 deletions(-)
 create mode 100644 demoQuickSort.go
 create mode 100644 demoWalkDir.go
 create mode 100644 demo_test.go
 create mode 100644 go.sum
 create mode 100644 goroutine.go
 create mode 100644 goroutine_test.go
 create mode 100644 test/test.go

diff --git a/channel.go b/channel.go
index 02f4691..70a1ab7 100644
--- a/channel.go
+++ b/channel.go
@@ -1,7 +1,9 @@
 package goConcurrency
 
 import (
+	"fmt"
 	"math/rand"
+	"runtime"
 	"sync"
 	"time"
 )
@@ -137,6 +139,32 @@ func ChannelAsync() {
 	wg.Wait()
 }
 
+func ChannelGoroutineNumCtl() {
+	// 1 独立的goroutine输出goroutine数量
+	go func() {
+		for {
+			fmt.Println("NumGoroutine:", runtime.NumGoroutine())
+			time.Sleep(500 * time.Millisecond)
+		}
+	}()
+
+	// 2 初始化channel，设置缓冲大小（并发规模）
+	const size = 1024
+	ch := make(chan struct{}, size)
+
+	// 3 并发的goroutine
+	for {
+		// 一，启动goroutine前，执行 ch send
+		// 当ch的缓冲已满时，阻塞
+		ch <- struct{}{}
+		go func() {
+			time.Sleep(10 * time.Second)
+			// 二，goroutine结束时，接收一个ch中的元素
+			<-ch
+		}()
+	}
+}
+
 func ChannelDirectional() {
 	// 初始化数据
 	ch := make(chan int)    // 双向的channel
diff --git a/channel_test.go b/channel_test.go
index 6ddf9bf..530f7b6 100644
--- a/channel_test.go
+++ b/channel_test.go
@@ -18,6 +18,10 @@ func TestChannelAsync(t *testing.T) {
 	ChannelAsync()
 }
 
+func TestChannelGoroutineNumCtl(t *testing.T) {
+	ChannelGoroutineNumCtl()
+}
+
 func TestChannelDirectional(t *testing.T) {
 	ChannelDirectional()
 }
diff --git a/context.go b/context.go
index 683e25d..c5a7c89 100644
--- a/context.go
+++ b/context.go
@@ -106,7 +106,7 @@ func ContextCancelTime() {
 
 }
 
-func ContextCancel() {
+func ContextCancelCall() {
 	// 1. 创建cancelContext
 	ctx, cancel := context.WithCancel(context.Background())
 
diff --git a/context_test.go b/context_test.go
index dd3562d..d29f37a 100644
--- a/context_test.go
+++ b/context_test.go
@@ -10,8 +10,8 @@ func TestContextCancelDeep(t *testing.T) {
 	ContextCancelDeep()
 }
 
-func TestContextCancel(t *testing.T) {
-	ContextCancel()
+func TestContextCancelCall(t *testing.T) {
+	ContextCancelCall()
 }
 
 func TestContextValue(t *testing.T) {
diff --git a/demoQuickSort.go b/demoQuickSort.go
new file mode 100644
index 0000000..8768922
--- /dev/null
+++ b/demoQuickSort.go
@@ -0,0 +1,78 @@
+package goConcurrency
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+// QuickSortConcurrency 快速排序调用函数
+func QuickSortConcurrency(arr []int) []int {
+	// 一：校验arr是否满足排序需要，至少要有2个元素
+	if arr == nil || len(arr) < 2 {
+		return arr
+	}
+
+	// 四：同步的控制
+	wg := &sync.WaitGroup{}
+	// 二：执行排序
+	// 初始排序整体[0, len(arr)-1]
+	wg.Add(1)
+	go quickSortConcurrency(arr, 0, len(arr)-1, wg)
+	wg.Wait()
+
+	// 三：返回结果
+	return arr
+}
+
+// 实现递归快排的核心函数
+// 接收arr，和排序区间的索引位置[l, r]
+func quickSortConcurrency(arr []int, l, r int, wg *sync.WaitGroup) {
+	// 一：-1wg的计数器
+	defer wg.Done()
+
+	// 二：判定是否需要排序， l < r
+	if l < r {
+		// 三：大小分区元素，并获取参考元素索引
+		mid := partition(arr, l, r)
+
+		// 四：并发对左部分排序
+		wg.Add(1)
+		go quickSortConcurrency(arr, l, mid-1, wg)
+
+		// 五：并发的对右部分排序
+		wg.Add(1)
+		go quickSortConcurrency(arr, mid+1, r, wg)
+	}
+}
+
+// 大小分区，返回参考元素索引
+func partition(arr []int, l, r int) int {
+	p := l - 1
+	for i := l; i <= r; i++ {
+		if arr[i] <= arr[r] {
+			p++
+			swap(arr, p, i)
+		}
+	}
+	return p
+}
+
+// 交换arr中i和j元素
+func swap(arr []int, i, j int) {
+	t := arr[i]
+	arr[i] = arr[j]
+	arr[j] = t
+}
+
+// 生成大的随机数组
+func GenerateRandArr(l int) []int {
+	// 生产大量的随机数
+	arr := make([]int, l)
+	rand.Seed(time.Now().UnixMilli())
+	for i := 0; i < l; i++ {
+		arr[i] = int(rand.Int31n(int32(l * 5)))
+	}
+
+	return arr
+}
diff --git a/demoWalkDir.go b/demoWalkDir.go
new file mode 100644
index 0000000..d911cc3
--- /dev/null
+++ b/demoWalkDir.go
@@ -0,0 +1,109 @@
+package goConcurrency
+
+// 并发遍历目录统计信息的Demo
+import (
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// WalkDir 外部调用的遍历目录统计信息的方法
+func WalkDir(dirs ...string) string {
+	// 一：保证至少有一个目录需要统计遍历
+	// 默认为当前目录
+	if len(dirs) == 0 {
+		dirs = []string{"."}
+	}
+
+	// 二：初始化变量，channel用于完成Size的传递，WaitGroup用于等待调度
+	filesizeCh := make(chan int64, 1)
+	wg := &sync.WaitGroup{}
+
+	// 三：启动多个Goroutine统计信息，取决于len(dirs)
+	for _, dir := range dirs {
+		wg.Add(1) // +1
+		// 并发的遍历统计每个目录的信息
+		go walkDir(dir, filesizeCh, wg)
+	}
+
+	// 四：启动累计运算的Goroutine
+	// 1.用户关闭filesizeCh
+	go func(filesizeCh chan int64, wg *sync.WaitGroup) {
+		//等待统计工作完成
+		wg.Wait()
+		// 关闭filesizeCh
+		close(filesizeCh)
+	}(filesizeCh, wg)
+	// 2.range的方式从filesizeCh中获取文件大小
+	// 3.将统计结果，使用channel传递出来
+	fileNumCh := make(chan int64, 1)
+	sizeTotalCh := make(chan int64, 1)
+	go func(filesizeCh <-chan int64, fileNumCh, sizeTotalCh chan<- int64) {
+		// 统计文件数，和文件整体大小
+		var fileNum, sizeTotal int64
+		// 遍历全部的filesizeCh元素，统计文件数量和大小，直到channel被关闭
+		for filesize := range filesizeCh {
+			// 累计文件数，和统计文件整体大小
+			fileNum++
+			sizeTotal += filesize
+		}
+		// 将统计结果发送到对于的Channel中
+		fileNumCh <- fileNum
+		sizeTotalCh <- sizeTotal
+	}(filesizeCh, fileNumCh, sizeTotalCh)
+
+	// 五：整理返回值
+	// size 的单位 Byte
+	// 需要的单位 MB
+	result := fmt.Sprintf("%d files %.2f MB\n", <-fileNumCh, float64(<-sizeTotalCh)/1e6) // 1024*1024
+	return result
+}
+
+// 遍历并统计某个特定目录的信息
+// 核心实现函数，完成递归，统计等
+func walkDir(dir string, filesizeCh chan<- int64, wg *sync.WaitGroup) {
+	// 一：wg计数器减少
+	defer wg.Done()
+	// 二：读取dir下的全部文件信息，并遍历
+	for _, fileinfo := range fileInfos(dir) {
+		// 三：根据dir下的文件信息
+		if fileinfo.IsDir() {
+			// 1. 如果目录，递归获取信息
+			// 子目录地址
+			subDir := filepath.Join(dir, fileinfo.Name())
+			// 递归调用，也是并发的，也需要wg统计
+			wg.Add(1)
+			go walkDir(subDir, filesizeCh, wg)
+		} else {
+			// 2. 如果不是，就是文件，统计文件大小，放入channel
+			filesizeCh <- fileinfo.Size() //Byte
+		}
+	}
+
+}
+
+// 获取某个目录下文件信息列表
+func fileInfos(dir string) []fs.FileInfo {
+	// 一，读取目录的全部文件
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		log.Println("WalkDir error:", err)
+		return []fs.FileInfo{} // nil
+	}
+
+	// 二，获取文件的文件信息
+	// DirEntry to FileInfo
+	infos := make([]fs.FileInfo, 0, len(entries))
+	for _, entry := range entries {
+		// 如果获取文件信息无错误，存储到infos中。
+		if info, err := entry.Info(); err == nil {
+			infos = append(infos, info)
+		}
+	}
+
+	// 三，返回
+	return infos
+}
diff --git a/demo_test.go b/demo_test.go
new file mode 100644
index 0000000..f73cca9
--- /dev/null
+++ b/demo_test.go
@@ -0,0 +1,23 @@
+package goConcurrency
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestWalkDir(t *testing.T) {
+	dirs := []string{
+		//`D:\apps\mashibing`,
+		//`D:\apps\kubernetes`,
+	}
+	fmt.Println(WalkDir(dirs...))
+}
+
+func TestQuickSortConcurrency(t *testing.T) {
+	//randArr := []int{
+	//	19, 21, 0, -8, 11, 12, 19, 7, 25, 33, 2, 5,
+	//}
+	randArr := GenerateRandArr(10000)
+	sortArr := QuickSortConcurrency(randArr)
+	fmt.Println(sortArr)
+}
diff --git a/go.mod b/go.mod
index 9bd2cca..2307b31 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module goConcurrency
 
 go 1.19
+
+require github.com/panjf2000/ants/v2 v2.7.1 // indirect
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..2794763
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/panjf2000/ants/v2 v2.7.1 h1:qBy5lfSdbxvrR0yUnZfaEDjf0FlCw4ufsbcsxmE7r+M=
+github.com/panjf2000/ants/v2 v2.7.1/go.mod h1:KIBmYG9QQX5U2qzFP/yQJaq/nSb6rahS9iEHkrCMgM8=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/goroutine.go b/goroutine.go
new file mode 100644
index 0000000..ee01fe5
--- /dev/null
+++ b/goroutine.go
@@ -0,0 +1,219 @@
+package goConcurrency
+
+import (
+	"fmt"
+	"github.com/panjf2000/ants/v2"
+	"log"
+	"runtime"
+	"sync"
+	"time"
+)
+
+func GoroutineGo() {
+	// 定义输出奇数的函数
+	printOdd := func() {
+		for i := 1; i <= 10; i += 2 {
+			fmt.Println(i)
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+
+	// 定义输出偶数的函数
+	printEven := func() {
+		for i := 2; i <= 10; i += 2 {
+			fmt.Println(i)
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+
+	// 顺序调用
+	//printOdd()
+	//printEven()
+
+	// 在 main goroutine 中，开启新的goroutine
+	// 并发调用
+	go printOdd()
+	go printEven()
+
+	// 典型的go
+	//go func() {}()
+	//func() {}()
+
+	// main goroutine 运行结束
+	// 内部调用的goroutine也就结束
+	time.Sleep(time.Second)
+}
+
+// 测试时，需要定义对应的测试文件，例如goroutine_test.go
+// 增加单元测试函数：
+//file:goroutine_test.go
+//package goConcurrency
+//
+//import "testing"
+//
+//func TestGoroutineGo(t *testing.T) {
+//	GoroutineGo()
+//}
+
+// 输出测试结果
+//goConcurrency> go test -run TestGoroutineGo
+//1
+//2
+//4
+//3
+//5
+//6
+//8
+//7
+//9
+//10
+//PASS
+//ok      goConcurrency   1.052s
+
+func GoroutineWG() {
+	// 1. 初始化 WaitGroup
+	wg := sync.WaitGroup{}
+	// 定义输出奇数的函数
+	printOdd := func() {
+		// 3.并发执行结束后，计数器-1
+		defer wg.Done()
+		for i := 1; i <= 10; i += 2 {
+			fmt.Println(i)
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+
+	// 定义输出偶数的函数
+	printEven := func() {
+		// 3.并发执行结束后，计数器-1
+		defer wg.Done()
+		for i := 2; i <= 10; i += 2 {
+			fmt.Println(i)
+			time.Sleep(100 * time.Millisecond)
+		}
+	}
+	// 在 main goroutine 中，开启新的goroutine
+	// 并发调用
+	// 2, 累加WG的计数器
+	wg.Add(2)
+	go printOdd()
+	go printEven()
+
+	// 其他的goroutine中wait
+	go func() {
+		wg.Wait()
+		fmt.Println("Wait in inner goroutine")
+	}()
+
+	// main goroutine 运行结束
+	// 内部调用的goroutine也就结束
+	// 4. 主goroutine等待
+	wg.Wait()
+	fmt.Println("after main wait")
+}
+
+func GoroutineNum() {
+	// 1. 统计当前存在的goroutine的数量
+	go func() {
+		for {
+			fmt.Println("NumGoroutine:", runtime.NumGoroutine())
+			time.Sleep(500 * time.Millisecond)
+		}
+	}()
+
+	// 2. 启动大量的goroutine
+	for {
+		go func() {
+			v := make([]int, 1024)
+			_ = v
+			fmt.Println("in goroutine")
+			time.Sleep(100 * time.Second)
+		}()
+	}
+
+}
+
+func GoroutineAnts() {
+	// 1. 统计当前存在的goroutine的数量
+	go func() {
+		for {
+			fmt.Println("NumGoroutine:", runtime.NumGoroutine())
+			time.Sleep(500 * time.Millisecond)
+		}
+	}()
+
+	// 2. 初始化协程池，goroutine pool
+	size := 1024
+	pool, err := ants.NewPool(size)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	// 保证pool被关闭
+	defer pool.Release()
+
+	// 3. 利用 pool，调度需要并发的大量goroutine
+	for {
+		// 向pool中提交一个执行的goroutine
+		err := pool.Submit(func() {
+			//v := make([]int, 1024)
+			//_ = v
+			//fmt.Println("in goroutine")
+			time.Sleep(100 * time.Second)
+		})
+		if err != nil {
+			log.Fatalln(err)
+		}
+	}
+
+}
+
+func GoroutineRandom() {
+	wg := sync.WaitGroup{}
+	// 同时启动多个goroutine输出不同的数字
+	workerNum := 10
+	wg.Add(workerNum)
+	for i := 0; i < workerNum; i++ {
+		go func(n int) {
+			wg.Done()
+			fmt.Println(n)
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+func GoroutineSched() {
+	wg := sync.WaitGroup{}
+	wg.Add(2)
+	// 设置为1个P在调度G
+	runtime.GOMAXPROCS(1) // 单线程模式
+	// 输出奇数
+	max := 100
+	go func() {
+		defer wg.Done()
+		for i := 1; i <= max; i += 2 {
+			fmt.Print(i, " ")
+
+			// 主动让出
+			runtime.Gosched()
+
+			// 增加执行时间
+			//time.Sleep(1 * time.Millisecond)
+		}
+	}()
+
+	// 输出偶数
+	go func() {
+		defer wg.Done()
+		for i := 2; i <= max; i += 2 {
+			fmt.Print(i, " ")
+			// 主动让出
+			runtime.Gosched()
+
+			// 增加执行时间
+			//time.Sleep(1 * time.Millisecond)
+		}
+	}()
+
+	wg.Wait()
+}
diff --git a/goroutine_test.go b/goroutine_test.go
new file mode 100644
index 0000000..af320f5
--- /dev/null
+++ b/goroutine_test.go
@@ -0,0 +1,27 @@
+package goConcurrency
+
+import "testing"
+
+func TestGoroutineGo(t *testing.T) {
+	GoroutineGo()
+}
+
+func TestGoroutineWG(t *testing.T) {
+	GoroutineWG()
+}
+
+func TestGoroutineNum(t *testing.T) {
+	GoroutineNum()
+}
+
+func TestGoroutineAnts(t *testing.T) {
+	GoroutineAnts()
+}
+
+func TestGoroutineRandom(t *testing.T) {
+	GoroutineRandom()
+}
+
+func TestGoroutineSched(t *testing.T) {
+	GoroutineSched()
+}
diff --git a/selectStmt.go b/selectStmt.go
index 456ec16..1465784 100644
--- a/selectStmt.go
+++ b/selectStmt.go
@@ -3,6 +3,8 @@ package goConcurrency
 import (
 	"fmt"
 	"math/rand"
+	"os"
+	"os/signal"
 	"sync"
 	"time"
 )
@@ -483,3 +485,34 @@ func SelectChannelCloseSignal() {
 
 	wg.Wait()
 }
+
+func SelectSignal() {
+	// 一：模拟一段长时间运行的goroutine
+	go func() {
+		for {
+			fmt.Println(time.Now().Format(".15.04.05.000"))
+			time.Sleep(300 * time.Millisecond)
+		}
+	}()
+
+	// 要求主goroutine等待上面的goroutine，方案：
+	// 1. wg.Wait(),要可以保证goroutine可以正常结束return
+	// 2. time.Sleep()，要保证时间周期的长度够用，但又不能太久
+	// 3. select{}，持久的阻塞
+
+	// 持久阻塞
+	//select {}
+
+	// 二，监控系统的中断信号,interrupt
+	// 1 创建channel，用于传递信号
+	chSignal := make(chan os.Signal, 1)
+	// 2 设置该channel可以监控哪些信号
+	signal.Notify(chSignal, os.Interrupt)
+	//signal.Notify(chSignal, os.Interrupt, os.Kill)
+	//signal.Notify(chSignal) // 全部类型的信号都可以使用该channel
+	// 3 监控channel
+	select {
+	case <-chSignal:
+		fmt.Println("received os signal: Interrupt")
+	}
+}
diff --git a/selectStmt_test.go b/selectStmt_test.go
index 6ddfbd4..9504c77 100644
--- a/selectStmt_test.go
+++ b/selectStmt_test.go
@@ -36,3 +36,7 @@ func TestSelectAll(t *testing.T) {
 func TestSelectChannelCloseSignal(t *testing.T) {
 	SelectChannelCloseSignal()
 }
+
+func TestSelectSignal(t *testing.T) {
+	SelectSignal()
+}
diff --git a/test/test.go b/test/test.go
new file mode 100644
index 0000000..ccba170
--- /dev/null
+++ b/test/test.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"fmt"
+	"sync"
+)
+
+func main() {
+	ch := make(chan int, 10)
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 10; i++ {
+			ch <- i
+			fmt.Println(i)
+		}
+		close(ch)
+	}()
+	wg.Wait()
+	for n := range ch {
+		fmt.Println("Read:", n)
+	}
+}