Non-Blocking Channel Write After Consumer Check

gistfile1.go

// Writes data to a channel without blocking if and only if the consumer is still alive
// The consumer provides a stop channel; if this channel is closed it is interpreted that the consumer no longer wants the data
// If data is written then this function returns true
func Write(data interface{}, stopChan chan interface{}, sendChan chan interface{}) (written bool, err error) {
    select {
    case _, ok := <-stopChan:
        if !ok {
            err = errors.New("consumer terminated")
            log.Printf("chwr: %s", err.Error())
        }   
    default:
        if written = WriteChanNonBlocking(data, sendChan); !written {
            log.Printf("chwr: fail write to consumer chan")
        }   
    }   

    return
}

// Writes data to a channel without blocking
// If data is written then this function returns true; in all other cases (including if data cannot be written without blocking), false is returned
func WriteChanNonBlocking(data interface{}, sendChan chan interface{}) (written bool) {
    select {
    case sendChan <- data:
        written = true
    default: // empty case - simply proceed
    }   

    return
}