client

var MakeBookstoreV2GrpcCall = func(addr, method string, header http.Header) (string, error) {
	var opts []grpc.DialOption
	opts = append(opts, grpc.WithInsecure())
	conn, err := grpc.Dial(addr, opts...)
	if err != nil {
		return "", fmt.Errorf("failed to connect to server: %v", err)
	}
	defer conn.Close()

	cli := bsgrpcv2.NewBookstoreClient(conn)
	ctx := context.Background()

	for key, valueList := range header {
		for _, value := range valueList {
			ctx = metadata.AppendToOutgoingContext(ctx, key, value)
		}
	}

	var respMsg proto.Message
	switch method {
	case "GetShelf":
		req := &bspbv2.GetShelfRequest{
			Shelf: 100,
		}
		respMsg, err = cli.GetShelf(ctx, req)
	default:
		return "", fmt.Errorf("unexpected method called")
	}

	if err != nil {
		return "", fmt.Errorf("%v got unexpected error: %v", method, err)
	}

	var marshaler jsonpb.Marshaler
	return marshaler.MarshalToString(respMsg)
}

var MakeHttpCallWithBody = func(addr, httpMethod, method, token string, bodyBytes []byte) (string, error) {
	var cli http.Client
	var req *http.Request

	if bodyBytes == nil {
		req, _ = http.NewRequest(httpMethod, fmt.Sprintf("http://%s%s", addr, method), nil)
	} else {
		req, _ = http.NewRequest(httpMethod, fmt.Sprintf("http://%s%s", addr, method), bytes.NewBuffer(bodyBytes))
	}
	req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))

	resp, err := cli.Do(req)
	if err != nil {
		return "", fmt.Errorf("http got error: %v", err)
	}
	defer resp.Body.Close()

	content, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("http response status is not 200 OK: %s, %s", resp.Status, utils.RpcStatusDeterministicJsonFormat(content))
	}

	return string(content), nil
}

var MakeHttpCallWithDecode = func(addr, httpMethod, method, token string, header http.Header) (string, string, error) {
	var cli http.Client
	req, _ := http.NewRequest(httpMethod, fmt.Sprintf("http://%s%s", addr, method), nil)

	if token != "" {
		req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))
	}

	addAllHeaders(req, header)

	resp, err := cli.Do(req)
	if err != nil {
		return "", "", fmt.Errorf("http got error: %v", err)
	}
	defer resp.Body.Close()

	encoding := getContentEncoding(resp.Header)

	var content []byte
	if encoding == "gzip" {
		gzipR, err := gzip.NewReader(resp.Body)
		if err != nil {
			return "", "", err
		}
		content, err = ioutil.ReadAll(gzipR)
	} else if encoding == "br" {
		content, err = ioutil.ReadAll(cbrotli.NewReader(resp.Body))
	} else {
		content, err = ioutil.ReadAll(resp.Body)
	}
	if err != nil {
		return "", "", err
	}

	if resp.StatusCode != http.StatusOK {
		return "", "", fmt.Errorf("http response status is not 200 OK: %s, %s", resp.Status, utils.RpcStatusDeterministicJsonFormat(content))
	}

	return string(content), encoding, nil
}