func fromJSON()

in spinnaker/fromjson.go [93:179]
65 lines of code
20 McCabe index (conditional complexity)

func fromJSON(js []byte) (*chaosmonkey.AppConfig, error) {
	parsed := new(parsedJSON)
	err := json.Unmarshal(js, parsed)

	if err != nil {
		return nil, errors.Wrap(err, "json unmarshal failed")
	}

	if parsed.Attributes == nil {
		return nil, errors.New("'attributes' field missing")
	}

	if parsed.Attributes.ChaosMonkey == nil {
		return nil, errors.New("'attributes.chaosMonkey' field missing")
	}

	cm := parsed.Attributes.ChaosMonkey

	if cm.Enabled == nil {
		return nil, errors.New("'attributes.chaosMonkey.enabled' field missing")
	}

	// Check if mean time between kills is missing.
	// If not enabled, it's ok if it's missing
	if *cm.Enabled && cm.MeanTimeBetweenKillsInWorkDays == nil {
		return nil, errors.New("attributes.chaosMonkey.meanTimeBetweenKillsInWorkDays missing")
	}

	if *cm.Enabled && cm.MinTimeBetweenKillsInWorkDays == nil {
		return nil, errors.New("attributes.chaosMonkey.minTimeBetweenKillsInWorkDays missing")
	}

	if *cm.Enabled && (*cm.MeanTimeBetweenKillsInWorkDays <= 0) {
		return nil, fmt.Errorf("invalid attributes.chaosMonkey.meanTimeBetweenKillsInWorkDays: %d", cm.MeanTimeBetweenKillsInWorkDays)
	}

	grouping := chaosmonkey.Cluster

	switch cm.Grouping {
	case "app":
		grouping = chaosmonkey.App
	case "stack":
		grouping = chaosmonkey.Stack
	case "cluster":
		grouping = chaosmonkey.Cluster
	default:
		// If not enabled, the user may not have specified a grouping at all,
		// in which case we stick with the default
		if *cm.Enabled {
			return nil, errors.Errorf("Unknown grouping: %s", cm.Grouping)
		}
	}

	var meanTime int
	var minTime int

	if cm.MeanTimeBetweenKillsInWorkDays != nil {
		meanTime = *cm.MeanTimeBetweenKillsInWorkDays
	}

	if cm.MinTimeBetweenKillsInWorkDays != nil {
		minTime = *cm.MinTimeBetweenKillsInWorkDays
	}

	// Exceptions must have a non-blank region field
	for _, exception := range cm.Exceptions {
		if exception.Account == "" {
			return nil, errors.New("missing account field in exception")
		}

		if exception.Region == "" {
			return nil, errors.New("missing region field in exception")
		}
	}

	cfg := chaosmonkey.AppConfig{
		Enabled:                        *cm.Enabled,
		RegionsAreIndependent:          cm.RegionsAreIndependent,
		Grouping:                       grouping,
		MeanTimeBetweenKillsInWorkDays: meanTime,
		MinTimeBetweenKillsInWorkDays:  minTime,
		Exceptions:                     cm.Exceptions,
		Whitelist:                      cm.Whitelist,
	}

	return &cfg, nil
}