go by example part 3

5-go-by-example/29-timeouts.go

@@ -0,0 +1,41 @@
+// bound execution time
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func main() {
+	// returns its result on a channel c1 after 2s
+	// channel is buffered, so the send in the goroutine is nonblocking
+	c1 := make(chan string, 1)
+	go func() {
+		time.Sleep(2 * time.Second)
+		c1 <- "result 1"
+	}()
+
+	// select implementing a timeout
+	// res awaits the result and <-time
+	// After awaits a value to be sent after the timeout
+	// select proceeds with the first receive that’s ready
+	select {
+	case res := <-c1:
+		fmt.Println(res)
+	case <-time.After(1 * time.Second):
+		fmt.Println("timeout 1")
+	}
+
+	// allow a longer timeout of 3s, then the receive from c2 will succeed and print the result
+	c2 := make(chan string, 1)
+	go func() {
+		time.Sleep(2 * time.Second)
+		c2 <- "result 2"
+	}()
+	select {
+	case res := <-c2:
+		fmt.Println(res)
+	case <-time.After(3 * time.Second):
+		fmt.Println("timeout 2")
+	}
+}