Refactor nebula go client implementation

Add editorconfig and use log library to output msg

Add print exec response result util function signature

Simplify nebula client

Merge open/authenticate and close/signout

Rename session ID

Rename Open/Close to Connect/Disconnect

Delete session ID parameter of Execute

Remove print response function temporarily

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+insert_final_newline = true
+charset = utf-8
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[{Makefile,go.mod,go.sum,*.go}]
+indent_style = tab
+indent_size = 2

.gitignore

@@ -10,3 +10,5 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+
+.DS_Store

README.md

@@ -4,3 +4,8 @@ Official Nebula Go client which communicates with the server using [fbthrift](ht
 
 Please be careful do not to modify the files in the graph directory, these codes were all generated by fbthrift.
 
+## Install
+
+```shell
+$ go get -u -v github.com/vesoft-inc/nebula-go
+```

client.go

@@ -7,10 +7,11 @@
 package ngdb
 
 import (
-	"fmt"
+	"log"
+	"time"
+
 	"github.com/facebook/fbthrift/thrift/lib/go/thrift"
 	"github.com/vesoft-inc/nebula-go/graph"
-	"time"
 )
 
 type GraphOptions struct {
@@ -24,8 +25,9 @@ var defaultGraphOptions = GraphOptions{
 }
 
 type GraphClient struct {
-	graph  graph.GraphServiceClient
-	option GraphOptions
+	graph     graph.GraphServiceClient
+	option    GraphOptions
+	sessionID int64
 }
 
 func WithTimeout(duration time.Duration) GraphOption {
@@ -43,7 +45,6 @@ func NewClient(address string, opts ...GraphOption) (client *GraphClient, err er
 	timeoutOption := thrift.SocketTimeout(options.Timeout)
 	addressOption := thrift.SocketAddr(address)
 	transport, err := thrift.NewSocket(timeoutOption, addressOption)
-
 	if err != nil {
 		return nil, err
 	}
@@ -55,36 +56,29 @@ func NewClient(address string, opts ...GraphOption) (client *GraphClient, err er
 	return graph, nil
 }
 
-func (client *GraphClient) Open() error {
-	err := client.graph.Transport.Open()
-	if err != nil {
+// Open transport and authenticate
+func (client *GraphClient) Connect(username, password string) error {
+	if err := client.graph.Transport.Open(); err != nil {
 		return err
 	}
-	return nil
-}
-
-func (client *GraphClient) Close() {
-	client.graph.Close()
-}
 
-func (client *GraphClient) Authenticate(username string, password string) (response *graph.AuthResponse, err error) {
-	if response, err := client.graph.Authenticate(username, password); err != nil {
-		return nil, err
+	if resp, err := client.graph.Authenticate(username, password); err != nil {
+		log.Printf("ErrorCode: %v, ErrorMsg: %s", resp.GetErrorCode(), resp.GetErrorMsg())
+		return err
 	} else {
-		return response, nil
+		client.sessionID = resp.GetSessionID()
+		return nil
 	}
 }
 
-func (client *GraphClient) Signout(sessionID int64) {
-	if err := client.graph.Signout(sessionID); err != nil {
-		fmt.Printf("Signout Failed : %v", err)
+// Close transport and signout
+func (client *GraphClient) Disconnect() error {
+	if err := client.graph.Close(); err != nil {
+		return err
 	}
+	return client.graph.Signout(client.sessionID)
 }
 
-func (client *GraphClient) Execute(sessionID int64, stmt string) (response *graph.ExecutionResponse, err error) {
-	if response, err := client.graph.Execute(sessionID, stmt); err != nil {
-		return nil, err
-	} else {
-		return response, nil
-	}
+func (client *GraphClient) Execute(stmt string) (*graph.ExecutionResponse, error) {
+	return client.graph.Execute(client.sessionID, stmt)
 }