Function createClient

kv/client.go:137–192

(backend string, prefix string, cfg StoreConfig, codec codec.Codec, role role, reg prometheus.Registerer, logger log.Logger)

}

func createClient(backend string, prefix string, cfg StoreConfig, codec codec.Codec, role role, reg prometheus.Registerer, logger log.Logger) (Client, error) {
	var client Client
	var err error

	switch backend {
	case "consul":
		client, err = consul.NewClient(cfg.Consul, codec, logger, reg)

	case "etcd":
		client, err = etcd.New(cfg.Etcd, codec, logger)

	case "inmemory":
		// If we use the in-memory store, make sure everyone gets the same instance
		// within the same process.
		inmemoryStoreInit.Do(func() {
			inmemoryStore, _ = consul.NewInMemoryClient(codec, logger, reg)
		})
		// however we swap the codec so that we can encode different type of values.
		client = inmemoryStore.WithCodec(codec)

	case "memberlist":
		kv, err := cfg.MemberlistKV()
		if err != nil {
			return nil, err
		}
		client, err = memberlist.NewClient(kv, codec)
		if err != nil {
			return nil, err
		}

	case "multi":
		client, err = buildMultiClient(cfg, codec, reg, logger)

	// This case is for testing. The mock KV client does not do anything internally.
	case "mock":
		client, err = buildMockClient(logger)

	default:
		return nil, fmt.Errorf("invalid KV store type: %s", backend)
	}

	if err != nil {
		return nil, err
	}

	if prefix != "" {
		client = PrefixClient(client, prefix)
	}

	// If no Registerer is provided return the raw client.
	if reg == nil {
		return client, nil
	}

	return newMetricsClient(backend, client, prometheus.WrapRegistererWith(role.Labels(), reg)), nil
}

func buildMultiClient(cfg StoreConfig, codec codec.Codec, reg prometheus.Registerer, logger log.Logger) (Client, error) {