From 5561c4bb48fe44ee9d38593356cda91c9058ca70 Mon Sep 17 00:00:00 2001
From: YuJack <jk82421@gmail.com>
Date: Tue, 6 Sep 2022 00:06:13 +0800
Subject: [PATCH] feat: add other-graceful

---
 README.md                   |  8 ++++-
 other/01-graceful/README.md | 10 ++++++
 other/01-graceful/main.go   | 66 +++++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 other/01-graceful/README.md
 create mode 100644 other/01-graceful/main.go

diff --git a/README.md b/README.md
index 2629a40..bb79de9 100644
--- a/README.md
+++ b/README.md
@@ -10,4 +10,10 @@
 | 1      | [Generator](./01-generator)               | 
 | 2      | [Fan-In](./02-fan-in)                     | 
 | 3      | [Fan-Out](./03-fan-out)                   | 
-| 4      | [Fan-In and Fan-Out](./04-fan-in-fan-out) | 
+| 4      | [Fan-In and Fan-Out](./04-fan-in-fan-out) |
+
+# 其他相關使用
+
+| Number | Name                                     |
+|--------|------------------------------------------|
+| 1      | [Graceful Shutdown](./other/01-graceful) | 
\ No newline at end of file
diff --git a/other/01-graceful/README.md b/other/01-graceful/README.md
new file mode 100644
index 0000000..b08d51a
--- /dev/null
+++ b/other/01-graceful/README.md
@@ -0,0 +1,10 @@
+# Graceful Shutdown
+
+通常應用程式在接受到 `kill -9` `kill -15` 等等相關訊號會直接關閉，但是實際上可以透過程式去處理取得這些 `signal` 時，要怎麼安全地關閉應用程式。
+
+
+參考 [Graceful Shutdown Example Code](./main.go)
+
+在範例程式中，可以試著換成 `newNormalContext`，並且在印出 0 的時候去中斷程式，會看到使用 `newNormalContext` 時並不會看到 1 被印出來，就意外的被中斷。
+
+但是當使用 `newGracefulContext` 接收 signal 的情況下，可以做一些後續收尾的動作。所以用這個 `newGracefulContext` 看到 0 的時候去中斷程式，會看到 1 被印出來。
\ No newline at end of file
diff --git a/other/01-graceful/main.go b/other/01-graceful/main.go
new file mode 100644
index 0000000..c909393
--- /dev/null
+++ b/other/01-graceful/main.go
@@ -0,0 +1,66 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"time"
+)
+
+func newNormalContext() context.Context {
+	return context.Background()
+}
+
+func newGracefulContext() context.Context {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	go func() {
+		sig := make(chan os.Signal)
+		signal.Notify(sig) // accept all signal
+		defer signal.Stop(sig)
+
+		select {
+		case <-ctx.Done():
+		case <-sig:
+			cancel()
+		}
+
+		fmt.Println("graceful shutdown")
+	}()
+
+	return ctx
+}
+
+func main() {
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+
+	ctx := newGracefulContext()
+	//ctx := newNormalContext()
+	go func(ctx context.Context) {
+		defer wg.Done()
+
+		data := 0
+		fmt.Println(data)
+
+		// simulate the hard work, then set data of 1
+		time.Sleep(2 * time.Second)
+		data = 1
+		fmt.Println(data)
+
+		select {
+		case <-ctx.Done():
+			fmt.Println("skip following job")
+			return
+		default:
+		}
+
+		time.Sleep(2 * time.Second)
+		data = 2
+		fmt.Println(data)
+	}(ctx)
+
+	wg.Wait()
+}