Using context to handle timeouts

timeout_with_context.go

package main

import (
    "fmt"
    "sync"
    "time"

    "golang.org/x/net/context"
)

var (
    wg sync.WaitGroup
)

func work(ctx context.Context) error {
    defer wg.Done()

    for i := 0; i < 1000; i++ {
        select {
        case <-time.After(2 * time.Second):
            fmt.Println("Doing some work ", i)

        // we received the signal of cancelation in this channel    
        case <-ctx.Done():
            fmt.Println("Cancel the context ", i)
            return ctx.Err()
        }
    }
    return nil
}

func main() {   
    ctx, cancel := context.WithTimeout(context.Background(), 4*time.Second)
    defer cancel()

    fmt.Println("Hey, I'm going to do some work")

    wg.Add(1)
    go work(ctx)
    wg.Wait()

    fmt.Println("Finished. I'm going home")
}