Исходники и презентации

lessons/contexts/context_with_cancel/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"sync"
+	"time"
+)
+
+func receiveWeather(ctx context.Context, result chan struct{}, idx int) {
+	randomTime := time.Duration(rand.Intn(5000)) * time.Millisecond
+
+	timer := time.NewTimer(randomTime)
+	defer timer.Stop()
+
+	select {
+	case <-timer.C:
+		fmt.Printf("finished: %d\n", idx)
+		result <- struct{}{}
+	case <-ctx.Done():
+		fmt.Printf("canceled: %d\n", idx)
+	}
+}
+
+func main() {
+	wg := sync.WaitGroup{}
+	wg.Add(10)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	result := make(chan struct{}, 10)
+	for i := 0; i < 10; i++ {
+		go func(idx int) {
+			defer wg.Done()
+			receiveWeather(ctx, result, idx)
+		}(i)
+	}
+
+	<-result
+	cancel()
+
+	wg.Wait()
+}