Prevent Unnecessary Computation in Broadcaster (internal/broadcast/dispatcher.go) #126

// broadcaster is run in a goroutine and handles the dispatching of certs to clients.
func (bm *Dispatcher) broadcaster() {
	for {
		// Take entry out of broadcast channel and generate JSON representations for the entry.
		entry := <-bm.MessageQueue
		computeBytes := entryByteComputer(&entry)

		bm.clientLock.RLock()

		for _, c := range bm.clients {
			data, err := computeBytes(c.SubType())
			// This should never happen, but if it does, we log it and skip the client.
			if err != nil {
				log.Printf("%s on client '%s'. Skipping this client!\n", err.Error(), c.Name())
				continue
			}

			c.Write(data)
		}

		bm.clientLock.RUnlock()
	}
}

// Compute and cache bytes as per necessity
func entryByteComputer(entry *models.Entry) func(subType SubscriptionType) ([]byte, error) {
	dataLite := []byte{}
	isDataLiteComputed := false

	dataFull := []byte{}
	isDataFullComputed := false

	dataDomain := []byte{}
	isDataDomainComputed := false

	return func(subType SubscriptionType) ([]byte, error) {
		switch subType {
		case SubTypeLite:
			if !isDataLiteComputed {
				dataLite = entry.JSONLite()
				isDataLiteComputed = true
			}
			return dataLite, nil

		case SubTypeFull:
			if !isDataFullComputed {
				dataFull = entry.JSON()
				isDataFullComputed = true
			}
			return dataFull, nil

		case SubTypeDomain:
			if !isDataDomainComputed {
				dataDomain = entry.JSONDomains()
				isDataDomainComputed = true
			}
			return dataDomain, nil

		default:
			return []byte{}, fmt.Errorf("Unknown subscription type '%d'", subType)
		}
	}
}