Исходники и презентации

lessons/contexts/errgroup_with_ctx/go.mod

@@ -0,0 +1,5 @@
+module errgroup
+
+go 1.20
+
+require golang.org/x/sync v0.6.0

lessons/contexts/errgroup_with_ctx/go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
+golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=

lessons/contexts/errgroup_with_ctx/main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math/rand"
+	"time"
+
+	"golang.org/x/sync/errgroup"
+)
+
+func main() {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	group, groupCtx := errgroup.WithContext(ctx)
+	for i := 0; i < 10; i++ {
+		group.Go(func() error {
+			timeout := time.Second * time.Duration(rand.Intn(10))
+
+			timer := time.NewTimer(timeout)
+			defer timer.Stop()
+
+			select {
+			case <-timer.C:
+				fmt.Println("timeout")
+				return errors.New("error")
+			case <-groupCtx.Done():
+				fmt.Println("canceled")
+				return nil
+			}
+		})
+	}
+
+	if err := group.Wait(); err != nil {
+		fmt.Println(err.Error())
+	}
+}