add: go context

go/context/context.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+func main() {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	go performTask(ctx)
+
+	select {
+	case <-ctx.Done():
+		fmt.Printf("%T\n", ctx)
+		fmt.Println(ctx)
+		fmt.Printf("%T\n", ctx.Done())
+		fmt.Println(ctx.Done())
+		fmt.Println("Task timeout")
+	}
+}
+
+// If performTask is not finished within 2 seconds, the program terminates
+func performTask(ctx context.Context) {
+	select {
+	case <-time.After(5 * time.Second):
+		fmt.Println("Task completed")
+	}
+
+}

go/contextCancel/contextCancel.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+func main() {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	go task(ctx)
+
+	time.Sleep(2 * time.Second)
+	cancel()
+	time.Sleep(1 * time.Second)
+}
+
+func task(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			fmt.Println("Task terminated")
+			return
+		default:
+			fmt.Println("Doing task")
+			time.Sleep(300 * time.Millisecond)
+		}
+	}
+
+}