What happened:
当java端的Date是null，go端decode将会报错，如果使用*time.Time可ui接收null，但是将无法接收正常Date
What you expected to happen:
抛出的异常：
ERROR [email protected]/session.go:558 [session.handlePackage] error:decObject illegal object type tag:74 github.com/dubbogo/hessian2.(*Decoder).decObject
How to reproduce it (as minimally and precisely as possible):
go 作为 client 端，java作为server端，使用dubbogo框架进行调用

Anything else we need to know?:

When compiling the source code, remind the user to be careful with the architecture.

cd dubbo/go-client
#linux, mac windows represent the os
#release, dev and test represent the environment
sh ./assembly/linux/release.sh

For example:

sh ./asssembly/$ARCH/$ENV.sh 

where $ARCH = [linux | mac | windows] and $ENV = [ release | dev | test]

Example: sh ./assembly/linux/release.sh

当在服务端启动过程中，多次尝试启停zookeeper，一般大于3次后。下一次连接上zk，进行服务的注册操作，zk会返回ErrNodeExists错误。而程序zk_client.go RegisterTemp方法中忽略了该错误，认为服务已经注册，导致zk服务注册失败。

After transfer to Apache, there is no need to have CLAassistant any more.

What happened:

There are these problems, when high concurrency and continuous stress testing:

• 'read tcp io timeout' is frequent
• High CPU and memory footprint

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

What would you like to be added:

在dubbo协议下，go-client能通过传入配置参数的形式实例化一个dubbo客户端。

Why is this needed:
当go-client调用dubbo接口时，必须代码实现一个javabean的描述。这个使业务端如果要动态调用十分不方便。
比如服务端新增了一个接口，客户单必须更改代码，不能通过更改配置实现。
比如go服务要做一个网关形式的服务，无法完成一些透传接口的工作
比如接口过多，go客户端将会需要很多代码描述。

go-server启动service后，启动go-client。但是client报错：
panic: Failed to invoke the method GetUser in the service

(2/1)from the registry zookeeper://:@127.0.0.1:2181?group=&registry=zookeeper&registry.role=0&registry.timeout=3s on the consumer 192.168.99.1 using the dubbo version 2.5.3. Last error is can not find go type name in registry.

在zookeeper里有这个service：

[zk: localhost:2181(CONNECTED) 76] ls /dubbo/com.lagou.chenlei.demo.main.UserService/providers
[dubbo://10.71.8.99:12345/com.xxx.demo.main.UserService?anyhost=true&app.version=1.0&application=BDTService&category=providers&cluster=failover&dubbo=dubbo-provider-golang-2.5.3&environment=dev&group=&interface=com.xxx.demo.main.UserService&ip=192.168.99.1&loadbalance=random&methods.GetUser.loadbalance=&methods.GetUser.retries=0&methods.GetUser.weight=0&module=dubbogo+user-info+server&name=BDTService&organization=ikurento.com&owner=ZX&pid=59371&retries=0&side=provider&timestamp=1558520537&version=&warmup=100]

而这个timeout的来源其实是server端的Registry_Config配置，在这个配置中，这个单位是秒，并且默认是5。而在SetServiceReadDeadLine中其实默认单位是ms。
这样会造成client端在等待server端返回结果的conn中，等5ms就会超时。造成i/o timeout的bug。

like java GenericService

望支持

What would you like to be added:

• 1 using getty task pool to improve network throughout;
• 2 add asyccallcaback;

What happened:
当多个dubbo provider的场景下，若有某一个网络不可达，同时客户端进行尝试连接，返回
net.DialTimeout(addr xxx:, timeout:3e+09) = error:dial tcp xxx: i/o timeout，并且不会进行自动的轮询切换
What you expected to happen:
当多个dubbo provider的场景下，consumer发起请求时，若有部分provider不可达(无论是网络原因还是provider自身的原因)，consumer应自动切换，并尝试连接别的provider
How to reproduce it (as minimally and precisely as possible):

1. 提供多个dubbo provider场景
2. 可以禁用其中的某一个（达到不可达的目的）
3. consumer发起请求，当请求到达被禁用的provider节点的时候，一直显示i/o timeout，并且不会进行自动的轮询切换
   dubbo providers :
   
   client timeout：
   

Anything else we need to know?:

What would you like to be added:
add failfastCluster

Why is this needed:
be consistent with java version

What happened:

I run the unit test of logger_test.go on win10, and result is below:

What you expected to happen:

Unit test pass.

How to reproduce it (as minimally and precisely as possible):

Click run buttom:

Anything else we need to know?:

• platform: win10

钉钉群号: 23331795

what time can be support Hessian Codec

I want use golang to call java Provider . but defualt Codec is Hessian not support .

java与go接入问题：
现在我们与go对接，有一个问题，java的序列化go不能用，如果接入dubbo-go客户端，这个问题还要考虑么
我们现在用的是2.6.2的默认的序列化
dubbo://，hessian2
谢谢

How to quick start go-for-apache-dubbo.

What would you like to be added:

Why is this needed:
be consistent with javaimpl

java registry unregister部分的源码，unregister这个的用途是：
1.provider在启动时也会启动registry的监听，当发现registry上注册的service内容跟本地刚启动时注册的service不一致时，就会刷新registry。
2.qos，允许运维人员对服务进行动态上下限。http://dubbo.apache.org/zh-cn/blog/introduction-to-dubbo-qos.html

1和2需求，暂时非紧急需求，先记个issue后面再完善。

Go for Apache Dubbo can be changed to dubbo-go now~

What happened:

OpenJDK 64-Bit Server VM warning: Ignoring option PermSize; support was removed in 8.0
OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
Unrecognized VM option 'UseCMSCompactAtFullCollection'
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

What you expected to happen:

Server can start

How to reproduce it (as minimally and precisely as possible):

cd dubbo/java-server/target
tar -zxvf user-info-server-0.2.0-assembly.tar.gz
cd ./user-info-server-0.2.0
sh ./bin/server.sh start

Anything else we need to know?:

The option UseCMSCompactAtFullCollection is no longer supported in Java 11. It is better to remove it.

What happened:
I use go client to call go server. Why I have to implement the pojo method named "JavaClassName"?

What you expected to happen:
Rename name .Or I do not need to register pojo when go client calling go server.
How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

1.go-client can not parse POJO in right way when java-server provide "Byte" as return
panic: Failed to invoke the method getTuple in the service com.*******.TupleProvider. Tried 3 times of the providers [dubbo://:@192.168.97.78:13675/com.*******.TupleProvider?group=&version= dubbo://:@192.168.97.78:13675/com.*******.TupleProvider?group=&version= dubbo://:@192.168.97.78:13675/com.*******.TupleProvider?group=&version=] (3/1)from the registry zookeeper://:@192.168.11.29:2181?group=&registry=zookeeper&registry.role=0&registry.timeout=3s on the consumer 192.168.97.78 using the dubbo version 2.6.0. Last error is unknown struct member type: int8.
2.go-client can not invoke nonparameter method provides by java-server
panic: runtime error: index out of range

public class Tuple implements Serializable {
    private static final long serialVersionUID = -1L;

    Integer Integer;
    Byte Byte;
    Short Short;
    Long Long;
    int i;
    byte b;
    short s;
    long l;
}

public interface TupleProvider {

    Tuple getTuple(Integer i);

    Tuple getTheTuple();
}


@Component
public class TupleProviderImpl implements TupleProvider {

    @Override
    public Tuple getTuple(Integer i) {
        return getTheTuple();
    }

    @Override
    public Tuple getTheTuple() {
        Tuple result = new Tuple();
        result.setB((byte) 1);
        result.setByte(Byte.valueOf("1"));
        result.setI(1);
        result.setInteger(Integer.valueOf("1"));
        result.setL(1L);
        result.setLong(Long.valueOf("1"));
        result.setS((short) 1);
        result.setShort(Short.valueOf("1"));
        return result;

    }
}

type Tuple struct {
	Byte    int8
	Short   int16
	Integer int32
	Long    int64
	B       int8
	S       int16
	I       int32
	L       int64
}

func (t Tuple) JavaClassName() string {
	return "com.***.Tuple"
}

type TupleProvider struct {
	GetTuple func(i int32) (tuple *Tuple, err error) `dubbo:"getTuple"`
	GetTheTuple func() (tuple *Tuple, err error) `dubbo:"getTheTuple"`
}

func (provider *TupleProvider) Service() string {
	return "com.***.TupleProvider"
}

func (provider *TupleProvider) Version() string {
	return ""
}

github.com/dubbo/go-for-apache-dubbo/dubbo/client.go:237:21: undefined: hessian.Heartbeat

What happened:
when set p2p module without registry , provider side will not be connected.
What you expected to happen:
consumer can invoke the service in provider by p2p.
How to reproduce it (as minimally and precisely as possible):
consumer & provider without registry configuration and consumer set "url" as provider's address.
Anything else we need to know?:

zk_client.go line248行，当zookeeper在server或者client运行时关掉，z.conn会为nil，则zk重连不会生效。

1. 环境变量问题

• 如果没有配置环境变量，可以将os.Getenv去掉，CONF_CONSUMER_FILE_PATH直接给配置文件地址
• confConFile = os.Getenv(constant.CONF_CONSUMER_FILE_PATH)
• confProFile = os.Getenv(constant.CONF_PROVIDER_FILE_PATH)
  改为
• confConFile = constant.CONF_CONSUMER_FILE_PATH
• confProFile = constant.CONF_PROVIDER_FILE_PATH

2. 在IDE(vscode or Goland)项目运行时报未声明

• 选中client.go user.go version.go同时运行
  待更新中...

such as gopkg, govendor ...

The attachments will missing when decode with unexported field of struct:
https://github.com/dubbo/go-for-apache-dubbo/blob/31e1a220cfd8d38ca9bbdff043913a803ac90ac7/protocol/dubbo/readwriter.go#L121

What happened:

Maven build failure on Java 11.

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.257 s
[INFO] Finished at: 2019-06-06T14:56:32+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project user-info-server: Compilation failure: Compilation failure:
[ERROR] Source option 5 is no longer supported. Use 6 or later.
[ERROR] Target option 1.5 is no longer supported. Use 1.6 or later.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

What you expected to happen:

Build pass

How to reproduce it (as minimally and precisely as possible):

cd example/dubbo/java-server and run sh build.sh

Anything else we need to know?:

Proposed fix

diff --git a/examples/dubbo/java-server/pom.xml b/examples/dubbo/java-server/pom.xml
index 9751578..da9c8b8 100644
--- a/examples/dubbo/java-server/pom.xml
+++ b/examples/dubbo/java-server/pom.xml
@@ -11,9 +11,12 @@
     <description>The demo provider module of dubbo project</description>
     <properties>
         <skip_maven_deploy>false</skip_maven_deploy>
-
         <dubbo-version>2.6.5</dubbo-version>
         <dubbo-jsonrpc-version>1.0.1</dubbo-jsonrpc-version>
+        <maven_compiler_version>3.6.0</maven_compiler_version>
+        <java_source_version>1.6</java_source_version>
+        <java_target_version>1.6</java_target_version>
+        <file_encoding>UTF-8</file_encoding>
     </properties>

     <dependencyManagement>
@@ -172,6 +175,19 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven_compiler_version}</version>
+                <configuration>
+                    <compilerArgument>-proc:none</compilerArgument>
+                    <fork>true</fork>
+                    <source>${java_source_version}</source>
+                    <target>${java_target_version}</target>
+                    <encoding>${file_encoding}</encoding>
+                </configuration>
+            </plugin>
         </plugins>
     </build>

jsonrpc 2.0 server feature list:
service registration based on zookeeper;
using jsonrpc 2.0 protocol;
using http transport;

如题，实际测试后发现在server运行过程中，将zookeeper停掉后再启动，server因为这段逻辑的存在，会将原来的service如com.ikurento.user.UserProvider重新注册为com.ikurento.user.UserProvider1

My code is as follows

go-server

java-client

The problem is that exception java catched is not contain the go error message which should be ‘invalid params: uid, name, cert could not be empty’.

In fact, java-client always catch as follows:

Failed to invoke the method Init in the service com.xxx.service.go.base.certify.api.CertifyService. Tried 1 times of the providers [10.71.8.70:20001] (1/1) from the registry 10.71.8.70:2181 on the consumer 10.71.8.70 using the dubbo version 2.6.3. Last error is: Failed to invoke remote method: Init, provider: dubbo://10.71.8.70:20001/com.xxx.service.go.base.certify.api.CertifyService?anyhost=true&app.version=1.0&application=consumer-of-certify-app&category=providers&check=false&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.xxx.service.go.base.certify.api.CertifyService&ip=192.168.99.1&loadbalance=random&methods=Init&methods.Init.loadbalance=random&methods.Init.retries=3&methods.Init.weight=0&module=dubbogo+certify+server&name=CertifyService&organization=test.com&owner=raychen&pid=71023&register.ip=10.71.8.70&remote.timestamp=1559621785&retries=0&service.filter=echo&side=consumer&timestamp=1559622450690&version=&warmup=100, cause: 0

go-for-apache-dubbo hessian2 doesn't support generics yet，like Response<T>。

test case:

• java

com.ikurento.user.Response<T> 

Responst<Integer> com.ikurento.user.UserProvider.sum(int a, int b)

• go

type Response struct {
	OK int32
	ERR int32
	Status int32
	Err string
        // How do I define this field
	Data interface{}
}


func (Response) JavaClassName() string {
	return "com.ikurento.user.Response"
}

func (r Response) String() string {
	return fmt.Sprintf(
		"Response{OK:%d, ERR:%d, Status:%d, Err:%s, Data:%s}",
		r.OK, r.ERR,r.Status,r.Err,r.Data,
	)
}

hessian.RegisterPOJO(&Response{})

response := &Response{}
err := conMap["com.ikurento.user.UserProvider"].GetRPCService().(*UserProvider).Sum(context.TODO(), []interface{}{1, 2}, response)

能否使用go dep或者go mod来管理包？

每个注册中心url都会在java中生成一个registry对象（即使是同一种注册中心类型如zookeeper，dubbo-java也会认为是多注册中心的情况）。所以java invoker的调用链为: RegistryAwareClusterInvoker(StaticDirectory) -> FailoverClusterInvoker(RegistryDirectory, will execute route) -> Invoker，需要先选取注册中心获取对应的缓存url list再去调用。
go版本目前未实现多种类注册中心，而对于同一种注册中心如zookeeper，在zk-client层就已经处理掉了，注册中心面向dubbo只有一个client实例。

func consumerInit(confConFile string) error {
if confConFile == "" {
return perrors.Errorf("application configure(consumer) file name is nil")
}
if path.Ext(confConFile) != ".yml" {
return perrors.Errorf("application configure file name{%v} suffix must be .yml", confConFile)
}
// when configCenter is apollo,configfile is remote config,can't read config.So hope provider read config through http.
confFileStream, err := ioutil.ReadFile(confConFile)
if err != nil {
return perrors.Errorf("ioutil.ReadFile(file:%s) = error:%v", confConFile, perrors.WithStack(err))
}
consumerConfig = &ConsumerConfig{}
err = yaml.Unmarshal(confFileStream, consumerConfig)
if err != nil {
return perrors.Errorf("yaml.Unmarshal() = error:%v", perrors.WithStack(err))
}
xxx
}

我们的服务运行在docker里，配置中心是携程的apollo。配置内容在配置中心上，通过配置中心来区分环境的。这里初始化直接读取本地的文件，实际上用不了。建议能够初始化时读取远程配置中心的配置，例如：apollo,etcd。

It should not panic when the function args list is empty.

项目对接时将bigdecimal改为string成功接收（证明不是连接问题）

1. 改回bigdecimal后使用golang中的float64测试报错

2. 然后再此时下方包中的Decimal，已经不能接收BigDecimal类型
   import "github.com/shopspring/decimal"

3. 尝试使用golang中的big类型同样失败

BigDecimal在Java中是常用的精确计算包装类，实际业务不可能改为浮点类型，所以该问题依旧是需要解决的问题

service provider improvement todo list:

• allow service provider return nil response

func (p *Provider) GetUser(userID int64) (*User, error) {
	...
	return nil, nil
}

• allow service provider none response

func (p *Provider) SetUserInfo(userInfo *User) error {
	...
	return nil
}

• allow service provider none request

func (p *Provider) TakeUser() (*User, error) {
	...
	return &User{}
}

• host bind ip auto detect when not being configured
• provider config map abstractions

conMap, _ := config.Load()
res, err := conMap["com.ikurento.user.UserProvider"].GetRPCService("com.ikurento.user.UserProvider").(*UserProvider).Echo(context.TODO(), "OK")
if err != nil {
	panic(err)
}

to

providerInstance, _ := config.Build()
res, err := providerInstance.GetRPCService("com.ikurento.user.UserProvider").(*UserProvider).Echo(context.TODO(), "OK")
if err != nil {
	panic(err)
}

Welcome to use dubbo-go. To know who is using it, pls append your org info as follow,

• Organization：Alibaba (Required)
• Location: Hangzhou, Zhejiang, China（Required）
• Contact: [email protected] (Optional)
• Purpose：used as our fundamental network transport lib (Required)
• Registry: zookeeper（Required）
• Version: 1.5.5（Required）
• Com/Org Logo：(Optional)
  Thanks again for your participation!

欢迎使用dubbogo，首先感谢你的使用，其次您可以参考下面的样例来提供您的信息以收集下使用场景：

* 组织：阿里巴巴（Required）
* 地点：**杭州（Required）
* 联系方式：[email protected]（Optional）
* 场景：阿里内部服务化改造（Required）
* 注册中心: zookeeper（Optional）
* 版本: 1.5.5（Optional）
* 公司图标：（Optional）

再次感谢你的参与!!!

What happened:
go get dubbo-go 1.0.0 有源码使用了旧包地址不能正常依赖

go get -u github.com/apache/dubbo-go
go: github.com/apache/[email protected]: parsing go.mod: unexpected module path "github.com/dubbo/go-for-apache-dubbo"
go get: error loading module requirements

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

What would you like to be added:

The code above may be placed in dubbo-go's code better than in user's code.

Why is this needed:

Does code above mean graceful exit? If this code is used frequently, we can move it to the dubbo-go's code so that users need not write it every time.

Consider one of following implementation, or all:

add struct field named method name and DubboName suffix

type UserProvider struct {
	GetUserDubboName struct{} `dubbo:"getUser"`

	user map[string]User
}

func (u *UserProvider) GetUser(ctx context.Context, req []interface{}, rsp *User) error {
	...
}

func (u *UserProvider) Service() string {
	return "com.my.UserProvider"
}

func (u *UserProvider) Version() string {
	return ""
}

add struct MethodAlias Method return map[string]string (init needed)

type UserProvider struct {
	user map[string]User
}

func (u *UserProvider) GetUser(ctx context.Context, req []interface{}, rsp *User) error {
	...
}

func (u *UserProvider) Service() string {
	return "com.my.UserProvider"
}

func (u *UserProvider) Version() string {
	return ""
}

func (u UserProvider) MethodAlias() map[string]string {
	return map[string]string{"GetUser":"getUser"}
}

go hessian client/server feature list:
service registration based on zookeeper;
using hessian protocol;
using tcp transport;

通过proxyFactory动态代理机制会返回客户端调用服务的invoker对象，开发者在使用时只需要正常调用接口方法。
golang没有动态代理机制，需要考虑一种方式来做到最小化调用。