Support functional option style API

pkg/api/api.go

@@ -19,38 +19,78 @@ import (
 	"github.com/opensergo/opensergo-go/pkg/transport/subscribe"
 )
 
+type ClientOptions struct {
+	connectRetryTimes uint
+}
+
+type ClientOption func(*ClientOptions)
+
+func (clientOptions *ClientOptions) ApplyClientOptions(opts ...ClientOption) {
+	if len(opts) > 0 {
+		for _, opt := range opts {
+			opt(clientOptions)
+		}
+	}
+}
+
+func NewDefaultClientOptions() *ClientOptions {
+	return &ClientOptions{
+		connectRetryTimes: 3,
+	}
+}
+
+func (opts *ClientOptions) ConnectRetryTimes() uint {
+	return opts.connectRetryTimes
+}
+
+func WithConnectRetryTimes(connectRetryTimes uint) ClientOption {
+	return func(opts *ClientOptions) {
+		opts.connectRetryTimes = connectRetryTimes
+	}
+}
+
 // SubscribeOptions represents the options of OpenSergo data subscription.
 type SubscribeOptions struct {
-	Subscribers []subscribe.Subscriber
-	Attachments map[string]interface{}
+	subscribers []subscribe.Subscriber
+	attachments map[string]interface{}
+}
+
+func (opts *SubscribeOptions) Subscribers() []subscribe.Subscriber {
+	return opts.subscribers
+}
+
+func (opts *SubscribeOptions) Attachments() map[string]interface{} {
+	return opts.attachments
 }
 
 type SubscribeOption func(*SubscribeOptions)
 
 // WithSubscriber provides a subscriber.
 func WithSubscriber(subscriber subscribe.Subscriber) SubscribeOption {
 	return func(opts *SubscribeOptions) {
-		if opts.Subscribers == nil {
-			opts.Subscribers = make([]subscribe.Subscriber, 0)
+		if opts.subscribers == nil {
+			opts.subscribers = make([]subscribe.Subscriber, 0)
 		}
-		opts.Subscribers = append(opts.Subscribers, subscriber)
+		opts.subscribers = append(opts.subscribers, subscriber)
 	}
 }
 
 // WithAttachment provides an attachment (key-value pair).
 func WithAttachment(key string, value interface{}) SubscribeOption {
 	return func(opts *SubscribeOptions) {
-		if opts.Attachments == nil {
-			opts.Attachments = make(map[string]interface{})
+		if opts.attachments == nil {
+			opts.attachments = make(map[string]interface{})
 		}
-		opts.Attachments[key] = value
+		opts.attachments[key] = value
 	}
 }
 
 // OpenSergoClient is the universal interface of OpenSergo client.
 type OpenSergoClient interface {
 	// Start the client.
 	Start() error
+	// Close the client.
+	Close() error
 	// SubscribeConfig subscribes data for given subscribe target.
 	SubscribeConfig(key model.SubscribeKey, opts ...SubscribeOption) error
 	// UnsubscribeConfig unsubscribes data for given subscribe target.

pkg/client/opensergo_client.go

@@ -33,8 +33,10 @@ import (
 
 // OpenSergoClient is the client to communicate with opensergo-control-plane.
 type OpenSergoClient struct {
-	host                   string
-	port                   uint32
+	host          string
+	port          uint32
+	clientOptions *api.ClientOptions
+
 	transportServiceClient transportPb.OpenSergoUniversalTransportServiceClient
 
 	subscribeConfigStreamPtr         atomic.Value // type of value is *client.subscribeConfigStream
@@ -48,7 +50,10 @@ type OpenSergoClient struct {
 }
 
 // NewOpenSergoClient returns an instance of OpenSergoClient, and init some properties.
-func NewOpenSergoClient(host string, port uint32) (*OpenSergoClient, error) {
+func NewOpenSergoClient(host string, port uint32, opts ...api.ClientOption) (*OpenSergoClient, error) {
+	clientOptions := api.NewDefaultClientOptions()
+	clientOptions.ApplyClientOptions(opts...)
+
 	address := host + ":" + strconv.FormatUint(uint64(port), 10)
 	clientConn, err := grpc.Dial(address, grpc.WithTransportCredentials(insecure.NewCredentials()))
 	if err != nil {
@@ -59,6 +64,7 @@ func NewOpenSergoClient(host string, port uint32) (*OpenSergoClient, error) {
 	openSergoClient := &OpenSergoClient{
 		host:                   host,
 		port:                   port,
+		clientOptions:          clientOptions,
 		transportServiceClient: transportServiceClient,
 		subscribeDataCache:     &subscribe.SubscribeDataCache{},
 		subscriberRegistry:     &subscribe.SubscriberRegistry{},
@@ -156,8 +162,8 @@ func (c *OpenSergoClient) SubscribeConfig(subscribeKey model.SubscribeKey, opts
 	}
 
 	// Register subscribers.
-	if len(options.Subscribers) > 0 {
-		for _, subscriber := range options.Subscribers {
+	if len(options.Subscribers()) > 0 {
+		for _, subscriber := range options.Subscribers() {
 			c.subscriberRegistry.RegisterSubscriber(subscribeKey, subscriber)
 		}
 	}

samples/main/main.go

@@ -15,9 +15,10 @@
 package main
 
 import (
+	"log"
+
 	"github.com/opensergo/opensergo-go/pkg/client"
 	"github.com/opensergo/opensergo-go/pkg/common/logging"
-	"log"
 
 	"github.com/opensergo/opensergo-go/pkg/api"
 	"github.com/opensergo/opensergo-go/pkg/configkind"
@@ -45,7 +46,7 @@ func StartAndSubscribeOpenSergoConfig() error {
 	// logging.NewFileLogger("./opensergo-universal-transport-service.log", logging.InfoLevel, logging.JsonFormat, true)
 
 	// Create a OpenSergoClient.
-	openSergoClient, err := client.NewOpenSergoClient("127.0.0.1", 10246)
+	openSergoClient, err := client.NewOpenSergoClient("127.0.0.1", 10246, api.WithConnectRetryTimes(5))
 	if err != nil {
 		return err
 	}