// shutdownChannel is a general closer function for channels
func shutdownChannel(channel *amqp.Channel, tag string) error {
// This waits for a server acknowledgment which means the sockets will have
// flushed all outbound publishings prior to returning. It's important to
// block on Close to not lose any publishings.
if err := channel.Cancel(tag, true); err != nil {
if amqpError, isAmqpError := err.(*amqp.Error); isAmqpError && amqpError.Code != 504 {
return fmt.Errorf("AMQP connection close error: %s", err)
}
}
if err := channel.Close(); err != nil {
return err
}
return nil
}