Context

Context is a way of passing information or enforcing timeouts when calling functions throughout your application as a single requests goes from layer to layer. This is usually passed as the first parameter in your functions if being used.

// create an empty context
ctx := context.Background()

// append value to context
ctx = context.WithValue(ctx, "key", "value")

value := ctx.Value("key")

Timeouts

ctx, cancel := context.WithTimeout(context.Background(), 2 * time.Second)

defer cancel() // can call before timeout
go longRunningFunc(ctx)

select {
case <-ctx.Done():
    fms.Println("done blocking main thread also!")
}
time.Sleep(2*time.Second)

func longRunningFunc(ctx context.Context) {
    for {
        select {
        case <-ctx.Done():
            fmt.Println("timed out")
            return
        default:
            fmt.Println("still processing")
        }
        time.Sleep(1*time.Second)
    }
}