Go-DDD-ElasticFactory.go

func NewClient(cfg Config) (*Client, error) {
	var addrs []string

	if len(cfg.Addresses) == 0 && cfg.CloudID == "" {
		addrs = addrsFromEnvironment()
	} else {
		if len(cfg.Addresses) > 0 && cfg.CloudID != "" {
			return nil, errors.New("cannot create client: both Addresses and CloudID are set")
		}

		if cfg.CloudID != "" {
			cloudAddr, err := addrFromCloudID(cfg.CloudID)
			if err != nil {
				return nil, fmt.Errorf("cannot create client: cannot parse CloudID: %s", err)
			}
			addrs = append(addrs, cloudAddr)
		}

		if len(cfg.Addresses) > 0 {
			addrs = append(addrs, cfg.Addresses...)
		}
	}

	urls, err := addrsToURLs(addrs)
	if err != nil {
		return nil, fmt.Errorf("cannot create client: %s", err)
	}

	if len(urls) == 0 {
		u, _ := url.Parse(defaultURL) // errcheck exclude
		urls = append(urls, u)
	}

	// TODO(karmi): Refactor
	if urls[0].User != nil {
		cfg.Username = urls[0].User.Username()
		pw, _ := urls[0].User.Password()
		cfg.Password = pw
	}

	tp, err := estransport.New(estransport.Config{
		URLs:         urls,
		Username:     cfg.Username,
		Password:     cfg.Password,
		APIKey:       cfg.APIKey,
		ServiceToken: cfg.ServiceToken,

		Header: cfg.Header,
		CACert: cfg.CACert,

		RetryOnStatus:        cfg.RetryOnStatus,
		DisableRetry:         cfg.DisableRetry,
		EnableRetryOnTimeout: cfg.EnableRetryOnTimeout,
		MaxRetries:           cfg.MaxRetries,
		RetryBackoff:         cfg.RetryBackoff,

		CompressRequestBody: cfg.CompressRequestBody,

		EnableMetrics:     cfg.EnableMetrics,
		EnableDebugLogger: cfg.EnableDebugLogger,

		DisableMetaHeader: cfg.DisableMetaHeader,

		DiscoverNodesInterval: cfg.DiscoverNodesInterval,

		Transport:          cfg.Transport,
		Logger:             cfg.Logger,
		Selector:           cfg.Selector,
		ConnectionPoolFunc: cfg.ConnectionPoolFunc,
	})
	if err != nil {
		return nil, fmt.Errorf("error creating transport: %s", err)
	}

	client := &Client{Transport: tp}
	client.API = esapi.New(client)

	if cfg.DiscoverNodesOnStart {
		go client.DiscoverNodes()
	}

	return client, nil
}