feat: add openim error handle

internal/msggateway/compressor_test.go

@@ -37,10 +37,16 @@ func TestCompressDecompress(t *testing.T) {
 
 		// compress
 		dest, err := compressor.CompressWithPool(src)
+		if err != nil {
+			t.Log(err)
+		}
 		assert.Equal(t, nil, err)
 
 		// decompress
 		res, err := compressor.DecompressWithPool(dest)
+		if err != nil {
+			t.Log(err)
+		}
 		assert.Equal(t, nil, err)
 
 		// check
@@ -60,10 +66,16 @@ func TestCompressDecompressWithConcurrency(t *testing.T) {
 
 			// compress
 			dest, err := compressor.CompressWithPool(src)
+			if err != nil {
+				t.Log(err)
+			}
 			assert.Equal(t, nil, err)
 
 			// decompress
 			res, err := compressor.DecompressWithPool(dest)
+			if err != nil {
+				t.Log(err)
+			}
 			assert.Equal(t, nil, err)
 
 			// check
@@ -99,6 +111,7 @@ func BenchmarkDecompress(b *testing.B) {
 
 	compressor := NewGzipCompressor()
 	comdata, err := compressor.Compress(src)
+	
 	assert.Equal(b, nil, err)
 
 	for i := 0; i < b.N; i++ {

internal/msggateway/init.go

@@ -23,14 +23,7 @@ import (
 
 // RunWsAndServer run ws server.
 func RunWsAndServer(rpcPort, wsPort, prometheusPort int) error {
-	fmt.Println(
-		"start rpc/msg_gateway server, port: ",
-		rpcPort,
-		wsPort,
-		prometheusPort,
-		", OpenIM version: ",
-		config.Version,
-	)
+	fmt.Println("start rpc/msg_gateway server, port: ", rpcPort, wsPort, prometheusPort, ", OpenIM version: ",config.Version)
 	longServer, err := NewWsServer(
 		WithPort(wsPort),
 		WithMaxConnNum(int64(config.Config.LongConnSvr.WebsocketMaxConnNum)),

internal/msggateway/long_conn.go

@@ -74,7 +74,8 @@ func (d *GWebSocket) GenerateLongConn(w http.ResponseWriter, r *http.Request) er
 
 	conn, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
-		return err
+		// The upgrader.Upgrade method usually returns enough error messages to diagnose problems that may occur during the upgrade
+		return errs.Wrap(err, "GenerateLongConn: WebSocket upgrade failed")
 	}
 	d.conn = conn
 	return nil
@@ -99,15 +100,15 @@ func (d *GWebSocket) SetReadDeadline(timeout time.Duration) error {
 
 func (d *GWebSocket) SetWriteDeadline(timeout time.Duration) error {
 	// TODO add error
-    if timeout <= 0 {
-        return errs.Wrap(errors.New("timeout must be greater than 0"))
-    }
+	if timeout <= 0 {
+		return errs.Wrap(errors.New("timeout must be greater than 0"))
+	}
 
 	// TODO SetWriteDeadline Future add error handling
 	if err := d.conn.SetWriteDeadline(time.Now().Add(timeout)); err != nil {
-        return errs.Wrap(err, "GWebSocket.SetWriteDeadline failed")
-    }
-    return nil
+		return errs.Wrap(err, "GWebSocket.SetWriteDeadline failed")
+	}
+	return nil
 }
 
 func (d *GWebSocket) Dial(urlStr string, requestHeader http.Header) (*http.Response, error) {

internal/msggateway/message_handler.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/OpenIMSDK/protocol/push"
 	"github.com/OpenIMSDK/tools/discoveryregistry"
+	"github.com/OpenIMSDK/tools/errs"
 
 	"github.com/go-playground/validator/v10"
 	"google.golang.org/protobuf/proto"
@@ -119,18 +120,18 @@ func NewGrpcHandler(validate *validator.Validate, client discoveryregistry.SvcDi
 func (g GrpcHandler) GetSeq(context context.Context, data *Req) ([]byte, error) {
 	req := sdkws.GetMaxSeqReq{}
 	if err := proto.Unmarshal(data.Data, &req); err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "GetSeq: error unmarshaling request")
 	}
 	if err := g.validate.Struct(&req); err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "GetSeq: validation failed")
 	}
 	resp, err := g.msgRpcClient.GetMaxSeq(context, &req)
 	if err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "GetSeq: error calling GetMaxSeq on msgRpcClient")
 	}
 	c, err := proto.Marshal(resp)
 	if err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "GetSeq: error marshaling response")
 	}
 	return c, nil
 }

internal/msgtransfer/init.go

@@ -45,8 +45,13 @@ import (
 )
 
 type MsgTransfer struct {
-	historyCH      *OnlineHistoryRedisConsumerHandler // 这个消费者聚合消息, 订阅的topic：ws2ms_chat, 修改通知发往msg_to_modify topic, 消息存入redis后Incr Redis, 再发消息到ms2pschat topic推送， 发消息到msg_to_mongo topic持久化
-	historyMongoCH *OnlineHistoryMongoConsumerHandler // mongoDB批量插入, 成功后删除redis中消息，以及处理删除通知消息删除的 订阅的topic: msg_to_mongo
+	// This consumer aggregated messages, subscribed to the topic:ws2ms_chat,
+	// the modification notification is sent to msg_to_modify topic, the message is stored in redis, Incr Redis,
+	// and then the message is sent to ms2pschat topic for push, and the message is sent to msg_to_mongo topic for persistence
+	historyCH *OnlineHistoryRedisConsumerHandler
+	// mongoDB batch insert, delete messages in redis after success,
+	// and handle the deletion notification message deleted subscriptions topic: msg_to_mongo
+	historyMongoCH *OnlineHistoryMongoConsumerHandler
 	ctx            context.Context
 	cancel         context.CancelFunc
 }
@@ -65,6 +70,7 @@ func StartTransfer(prometheusPort int) error {
 	if err = mongo.CreateMsgIndex(); err != nil {
 		return err
 	}
+
 	client, err := kdisc.NewDiscoveryRegister(config.Config.Envs.Discovery)
 	if err != nil {
 		return err
@@ -73,6 +79,7 @@ func StartTransfer(prometheusPort int) error {
 	if err := client.CreateRpcRootNodes(config.Config.GetServiceNames()); err != nil {
 		return err
 	}
+
 	client.AddOption(mw.GrpcClient(), grpc.WithTransportCredentials(insecure.NewCredentials()), grpc.WithDefaultServiceConfig(fmt.Sprintf(`{"LoadBalancingPolicy": "%s"}`, "round_robin")))
 	msgModel := cache.NewMsgCacheModel(rdb)
 	msgDocModel := unrelation.NewMsgMongoDriver(mongo.GetDatabase())
@@ -106,7 +113,7 @@ func NewMsgTransfer(msgDatabase controller.CommonMsgDatabase, conversationRpcCli
 }
 
 func (m *MsgTransfer) Start(prometheusPort int) error {
-	fmt.Println("start msg transfer", "prometheusPort:", prometheusPort)
+	fmt.Println("Start msg transfer", "prometheusPort:", prometheusPort)
 	if prometheusPort <= 0 {
 		return errs.Wrap(errors.New("prometheusPort not correct"))
 	}

internal/msgtransfer/online_history_msg_handler.go

@@ -155,15 +155,7 @@ func (och *OnlineHistoryRedisConsumerHandler) Run(channelID int) {
 				notStorageNotificationList,
 			)
 			if err := och.msgDatabase.MsgToModifyMQ(ctx, msgChannelValue.uniqueKey, conversationIDNotification, modifyMsgList); err != nil {
-				log.ZError(
-					ctx,
-					"msg to modify mq error",
-					err,
-					"uniqueKey",
-					msgChannelValue.uniqueKey,
-					"modifyMsgList",
-					modifyMsgList,
-				)
+				log.ZError(ctx, "msg to modify mq error", err, "uniqueKey", msgChannelValue.uniqueKey, "modifyMsgList", modifyMsgList)
 			}
 		}
 	}

internal/push/callback.go

@@ -31,12 +31,7 @@ func url() string {
 	return config.Config.Callback.CallbackUrl
 }
 
-func callbackOfflinePush(
-	ctx context.Context,
-	userIDs []string,
-	msg *sdkws.MsgData,
-	offlinePushUserIDs *[]string,
-) error {
+func callbackOfflinePush(ctx context.Context, userIDs []string, msg *sdkws.MsgData, offlinePushUserIDs *[]string) error {
 	if !config.Config.Callback.CallbackOfflinePush.Enable || msg.ContentType == constant.Typing {
 		return nil
 	}
@@ -59,10 +54,12 @@ func callbackOfflinePush(
 		AtUserIDs:       msg.AtUserIDList,
 		Content:         GetContent(msg),
 	}
+
 	resp := &callbackstruct.CallbackBeforePushResp{}
 	if err := http.CallBackPostReturn(ctx, url(), req, resp, config.Config.Callback.CallbackOfflinePush); err != nil {
 		return err
 	}
+	
 	if len(resp.UserIDs) != 0 {
 		*offlinePushUserIDs = resp.UserIDs
 	}

pkg/common/http/http_client.go

@@ -25,7 +25,6 @@ import (
 	"github.com/OpenIMSDK/protocol/constant"
 	"github.com/OpenIMSDK/tools/errs"
 	"github.com/OpenIMSDK/tools/log"
-
 	"github.com/openimsdk/open-im-server/v3/pkg/callbackstruct"
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
 )
@@ -102,7 +101,10 @@ func PostReturn(ctx context.Context, url string, header map[string]string, input
 		return err
 	}
 	err = json.Unmarshal(b, output)
-	return err
+	if err != nil {
+		return errs.Wrap(err, "PostReturn: JSON unmarshal failed")
+	}
+	return nil
 }
 
 func callBackPostReturn(ctx context.Context, url, command string, input interface{}, output callbackstruct.CallbackResp, callbackConfig config.CallBackConfig) error {
@@ -127,7 +129,6 @@ func callBackPostReturn(ctx context.Context, url, command string, input interfac
 	}
 	if err := output.Parse(); err != nil {
 		log.ZWarn(ctx, "callback parse failed", err, "url", url, "input", input, "response", string(b))
-		return err
 	}
 	log.ZInfo(ctx, "callback success", "url", url, "input", input, "response", string(b))
 	return nil

pkg/common/kafka/consumer.go

@@ -17,9 +17,8 @@ package kafka
 import (
 	"sync"
 
-	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
-
 	"github.com/IBM/sarama"
+	"github.com/OpenIMSDK/tools/errs"
 )
 
 type Consumer struct {
@@ -30,28 +29,33 @@ type Consumer struct {
 	Consumer      sarama.Consumer
 }
 
-func NewKafkaConsumer(addr []string, topic string) *Consumer {
-	p := Consumer{}
-	p.Topic = topic
-	p.addr = addr
-	consumerConfig := sarama.NewConfig()
-	if config.Config.Kafka.Username != "" && config.Config.Kafka.Password != "" {
-		consumerConfig.Net.SASL.Enable = true
-		consumerConfig.Net.SASL.User = config.Config.Kafka.Username
-		consumerConfig.Net.SASL.Password = config.Config.Kafka.Password
+func NewKafkaConsumer(addr []string, topic string, kafkaConfig *sarama.Config) (*Consumer, error) {
+	p := Consumer{
+		Topic: topic,
+		addr:  addr,
 	}
-	SetupTLSConfig(consumerConfig)
-	consumer, err := sarama.NewConsumer(p.addr, consumerConfig)
+
+	if kafkaConfig.Net.SASL.User != "" && kafkaConfig.Net.SASL.Password != "" {
+		kafkaConfig.Net.SASL.Enable = true
+	}
+
+	err := SetupTLSConfig(kafkaConfig)
 	if err != nil {
-		panic(err.Error())
+		return nil, err
+	}
+
+	consumer, err := sarama.NewConsumer(p.addr, kafkaConfig)
+	if err != nil {
+		return nil, errs.Wrap(err, "NewKafkaConsumer: creating consumer failed")
 	}
 	p.Consumer = consumer
 
 	partitionList, err := consumer.Partitions(p.Topic)
 	if err != nil {
-		panic(err.Error())
+		return nil, errs.Wrap(err, "NewKafkaConsumer: getting partitions failed")
 	}
 	p.PartitionList = partitionList
 
-	return &p
+	return &p, nil
+
 }

pkg/common/kafka/producer.go

@@ -94,7 +94,6 @@ func NewKafkaProducer(addr []string, topic string) (*Producer, error) {
 		}
 		time.Sleep(1 * time.Second) // Wait before retrying
 	}
-
 	// Panic if unable to create producer after retries
 	if err != nil {
 		return nil, errs.Wrap(errors.New("failed to create Kafka producer: " + err.Error()))

pkg/common/kafka/util.go

@@ -20,22 +20,28 @@ import (
 	"strings"
 
 	"github.com/IBM/sarama"
+	"github.com/OpenIMSDK/tools/errs"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
 	"github.com/openimsdk/open-im-server/v3/pkg/common/tls"
 )
 
 // SetupTLSConfig set up the TLS config from config file.
-func SetupTLSConfig(cfg *sarama.Config) {
+func SetupTLSConfig(cfg *sarama.Config) error {
 	if config.Config.Kafka.TLS != nil {
 		cfg.Net.TLS.Enable = true
-		cfg.Net.TLS.Config = tls.NewTLSConfig(
+		tlsConfig, err := tls.NewTLSConfig(
 			config.Config.Kafka.TLS.ClientCrt,
 			config.Config.Kafka.TLS.ClientKey,
 			config.Config.Kafka.TLS.CACrt,
 			[]byte(config.Config.Kafka.TLS.ClientKeyPwd),
 		)
+		if err != nil {
+			return errs.Wrap(err, "SetupTLSConfig: failed to set up TLS config")
+		}
+		cfg.Net.TLS.Config = tlsConfig
 	}
+	return nil
 }
 
 // getEnvOrConfig returns the value of the environment variable if it exists,

pkg/common/tls/tls.go

@@ -21,6 +21,7 @@ import (
 	"errors"
 	"os"
 
+	"github.com/OpenIMSDK/tools/errs"
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
 )
 
@@ -49,37 +50,41 @@ func readEncryptablePEMBlock(path string, pwd []byte) ([]byte, error) {
 }
 
 // NewTLSConfig setup the TLS config from general config file.
-func NewTLSConfig(clientCertFile, clientKeyFile, caCertFile string, keyPwd []byte) *tls.Config {
-	tlsConfig := tls.Config{}
+func NewTLSConfig(clientCertFile, clientKeyFile, caCertFile string, keyPwd []byte) (*tls.Config, error) {
+	var tlsConfig tls.Config
 
 	if clientCertFile != "" && clientKeyFile != "" {
 		certPEMBlock, err := os.ReadFile(clientCertFile)
 		if err != nil {
-			panic(err)
+			return nil, errs.Wrap(err, "NewTLSConfig: failed to read client cert file")
 		}
+
 		keyPEMBlock, err := readEncryptablePEMBlock(clientKeyFile, keyPwd)
 		if err != nil {
-			panic(err)
+			return nil, err
 		}
+
 		cert, err := tls.X509KeyPair(certPEMBlock, keyPEMBlock)
 		if err != nil {
-			panic(err)
+			return nil, errs.Wrap(err, "NewTLSConfig: failed to create X509 key pair")
 		}
 		tlsConfig.Certificates = []tls.Certificate{cert}
 	}
 
-	caCert, err := os.ReadFile(caCertFile)
-	if err != nil {
-		panic(err)
+	if caCertFile != "" {
+		caCert, err := os.ReadFile(caCertFile)
+		if err != nil {
+			return nil, errs.Wrap(err, "NewTLSConfig: failed to read CA cert file")
+		}
+
+		caCertPool := x509.NewCertPool()
+		if ok := caCertPool.AppendCertsFromPEM(caCert); !ok {
+			return nil, errors.New("NewTLSConfig: not a valid CA cert")
+		}
+		tlsConfig.RootCAs = caCertPool
 	}
-	caCertPool := x509.NewCertPool()
-	ok := caCertPool.AppendCertsFromPEM(caCert)
-	if !ok {
-		panic(errors.New("not a valid CA cert"))
-	}
-	tlsConfig.RootCAs = caCertPool
 
 	tlsConfig.InsecureSkipVerify = config.Config.Kafka.TLS.InsecureSkipVerify
 
-	return &tlsConfig
+	return &tlsConfig, nil
 }

pkg/rpcclient/conversation.go

@@ -23,6 +23,7 @@ import (
 	pbconversation "github.com/OpenIMSDK/protocol/conversation"
 	"github.com/OpenIMSDK/tools/discoveryregistry"
 	"github.com/OpenIMSDK/tools/errs"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
 )
@@ -36,7 +37,7 @@ type Conversation struct {
 func NewConversation(discov discoveryregistry.SvcDiscoveryRegistry) *Conversation {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImConversationName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	client := pbconversation.NewConversationClient(conn)
 	return &Conversation{discov: discov, conn: conn, Client: client}

pkg/rpcclient/friend.go

@@ -24,6 +24,7 @@ import (
 	"github.com/OpenIMSDK/tools/discoveryregistry"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 )
 
 type Friend struct {
@@ -35,7 +36,7 @@ type Friend struct {
 func NewFriend(discov discoveryregistry.SvcDiscoveryRegistry) *Friend {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImFriendName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	client := friend.NewFriendClient(conn)
 	return &Friend{discov: discov, conn: conn, Client: client}
@@ -62,7 +63,7 @@ func (f *FriendRpcClient) GetFriendsInfo(
 	return
 }
 
-// possibleFriendUserID是否在userID的好友中.
+// possibleFriendUserID Is PossibleFriendUserId's friends.
 func (f *FriendRpcClient) IsFriend(ctx context.Context, possibleFriendUserID, userID string) (bool, error) {
 	resp, err := f.Client.IsFriend(ctx, &friend.IsFriendReq{UserID1: userID, UserID2: possibleFriendUserID})
 	if err != nil {

pkg/rpcclient/group.go

@@ -28,6 +28,7 @@ import (
 	"github.com/OpenIMSDK/tools/utils"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 )
 
 type Group struct {
@@ -39,7 +40,7 @@ type Group struct {
 func NewGroup(discov discoveryregistry.SvcDiscoveryRegistry) *Group {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImGroupName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	client := group.NewGroupClient(conn)
 	return &Group{discov: discov, conn: conn, Client: client}

pkg/rpcclient/push.go

@@ -23,6 +23,7 @@ import (
 	"github.com/OpenIMSDK/tools/discoveryregistry"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 )
 
 type Push struct {
@@ -34,7 +35,7 @@ type Push struct {
 func NewPush(discov discoveryregistry.SvcDiscoveryRegistry) *Push {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImPushName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	return &Push{
 		discov: discov,
@@ -49,9 +50,6 @@ func NewPushRpcClient(discov discoveryregistry.SvcDiscoveryRegistry) PushRpcClie
 	return PushRpcClient(*NewPush(discov))
 }
 
-func (p *PushRpcClient) DelUserPushToken(
-	ctx context.Context,
-	req *push.DelUserPushTokenReq,
-) (*push.DelUserPushTokenResp, error) {
+func (p *PushRpcClient) DelUserPushToken(ctx context.Context, req *push.DelUserPushTokenReq) (*push.DelUserPushTokenResp, error) {
 	return p.Client.DelUserPushToken(ctx, req)
 }

pkg/rpcclient/third.go

@@ -24,8 +24,10 @@ import (
 
 	"github.com/OpenIMSDK/protocol/third"
 	"github.com/OpenIMSDK/tools/discoveryregistry"
+	"github.com/OpenIMSDK/tools/errs"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/common/config"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 )
 
 type Third struct {
@@ -38,35 +40,42 @@ type Third struct {
 func NewThird(discov discoveryregistry.SvcDiscoveryRegistry) *Third {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImThirdName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	client := third.NewThirdClient(conn)
 	minioClient, err := minioInit()
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	return &Third{discov: discov, Client: client, conn: conn, MinioClient: minioClient}
 }
 
 func minioInit() (*minio.Client, error) {
-	minioClient := &minio.Client{}
-	initUrl := config.Config.Object.Minio.Endpoint
-	minioUrl, err := url.Parse(initUrl)
+	// Retrieve MinIO configuration details
+	endpoint := config.Config.Object.Minio.Endpoint
+	accessKeyID := config.Config.Object.Minio.AccessKeyID
+	secretAccessKey := config.Config.Object.Minio.SecretAccessKey
+
+	// Parse the MinIO URL to determine if the connection should be secure
+	minioURL, err := url.Parse(endpoint)
 	if err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "minioInit: failed to parse MinIO endpoint URL")
 	}
+
+	// Determine the security of the connection based on the scheme
+	secure := minioURL.Scheme == "https"
+
+	// Setup MinIO client options
 	opts := &minio.Options{
-		Creds: credentials.NewStaticV4(config.Config.Object.Minio.AccessKeyID, config.Config.Object.Minio.SecretAccessKey, ""),
-		// Region: config.Config.Credential.Minio.Location,
+		Creds:  credentials.NewStaticV4(accessKeyID, secretAccessKey, ""),
+		Secure: secure,
 	}
-	if minioUrl.Scheme == "http" {
-		opts.Secure = false
-	} else if minioUrl.Scheme == "https" {
-		opts.Secure = true
-	}
-	minioClient, err = minio.New(minioUrl.Host, opts)
+
+	// Initialize MinIO client
+	minioClient, err := minio.New(minioURL.Host, opts)
 	if err != nil {
-		return nil, err
+		return nil, errs.Wrap(err, "minioInit: failed to create MinIO client")
 	}
+
 	return minioClient, nil
 }

pkg/rpcclient/user.go

@@ -19,6 +19,7 @@ import (
 	"strings"
 
 	"github.com/openimsdk/open-im-server/v3/pkg/authverify"
+	util "github.com/openimsdk/open-im-server/v3/pkg/util/genutil"
 
 	"google.golang.org/grpc"
 
@@ -42,7 +43,7 @@ type User struct {
 func NewUser(discov discoveryregistry.SvcDiscoveryRegistry) *User {
 	conn, err := discov.GetConn(context.Background(), config.Config.RpcRegisterName.OpenImUserName)
 	if err != nil {
-		panic(err)
+		util.ExitWithError(err)
 	}
 	client := user.NewUserClient(conn)
 	return &User{Discov: discov, Client: client, conn: conn}