func getFilterKeyValue()

in pkg/plugin/cloudtrace/cloudtrace.go [147:212]
49 lines of code
20 McCabe index (conditional complexity)

func getFilterKeyValue(qTFilter string) (key string, value string, err error) {
	// Filter part must be in form [key]:[value] from user
	qTFilterParts := strings.SplitN(qTFilter, ":", 2)
	if len(qTFilterParts) != 2 {
		return "", "", fmt.Errorf("bad filter [%s]. Must be in form [key]:[value]", qTFilter)
	}

	key = qTFilterParts[0]
	value = qTFilterParts[1]

	// OR for generic labels filter must be in form LABEL:[key]:[value] from user
	if strings.ToLower(key) == "label" {
		qTFilterParts := strings.SplitN(value, ":", 2)

		if len(qTFilterParts) != 2 {
			return "", "", fmt.Errorf("bad filter [%s]. Must be in form LABEL:[key]:[value]", qTFilter)
		}

		// Cloud Trace API should not have "LABEL:" in filter
		key = qTFilterParts[0]
		value = qTFilterParts[1]
	}

	// Convert key to Cloud Trace API expected form if needed
	switch key {
	case "RootSpan":
		key = "root"
	case "SpanName":
		key = "span"
	case "HasLabel":
		key = "label"
	case "MinLatency":
		key = "latency"
	case "URL":
		key = "url"
	case "Method":
		key = "method"
		// Currently matches the Google Cloud Trace UI filter, but ignores "service.version" matches
	case "Version":
		key = gaeServiceVersionKey
		// Currently matches the Google Cloud Trace UI filter, but ignores "service.name" matches
	case "Service":
		key = gaeServiceKey
	case "Status":
		key = "/http/status_code"
	}

	// If the value has less than 2 chars, no need to check for special filter chars
	if len(value) < 2 {
		return key, value, nil
	}

	firstChar := string(value[0])
	secondChar := string(value[1])

	// Move specials chars from the front of value to key for Google Cloud Trace compatibility
	if (secondChar == "^" && firstChar == "+") || (secondChar == "+" && firstChar == "^") {
		key = fmt.Sprintf("+^%s", key)
		value = value[2:]
	} else if firstChar == "+" || firstChar == "^" {
		key = fmt.Sprintf("%s%s", firstChar, key)
		value = value[1:]
	}

	return key, value, nil
}