Direct Example

Backend

In the development and testing environment, it is often necessary to bypass the registry and test the designated service provider, which may require point-to-point direct connection. The point-to-point direct connection method will be based on the service interface and ignore the list of providers in the registry. Interface A is configured point-to-point and does not affect interface B to get the list from the registry.

This example provides the Consumer point-to-point direct connection Provider based on Dubbo-Go to complete service calls to help better understand the connectivity of Dubbo-Go.

Introduction

├── go-client     
│   ├── cmd       
│   ├── conf      
│   └── pkg         
└── go-server     
    ├── cmd       
    ├── conf      
    ├── docker     
    ├── pkg
    └── tests
        └── integration

• go-server: The Service Provider
• go-client: The Service Consumer

Provider

Direct example code description:

1. Configure the Dubbo protocol, registry, service information, See server.yml

services:
  "UserProvider":
    registry: "demoZk"
    protocol : "dubbo"
    interface : "org.apache.dubbo.UserProvider"
    loadbalance: "random"
    warmup: "100"
    cluster: "failover"
    methods:
    - name: "GetUser"
      retries: 1
      loadbalance: "random"

2. Startup: Register the service

hessian.RegisterPOJO(&pkg.User{})
config.Load()
initSignal()

• Based on the hessian serialization protocol, using apache/dubbo-go-hessian2 RegisterPOJO register a POJO

• Dubbo Init: Registration service, See apache/dubbo-go/../config_loader.go

  • init router
  • init the global event dispatcher
  • start the metadata report if config set
  • reference config
  • service config
  • init the shutdown callback

• Init Signal ：

  func initSignal() {
      signals := make(chan os.Signal, 1)
      // It is not possible to block SIGKILL or syscall.SIGSTOP
      signal.Notify(signals, os.Interrupt, os.Kill, syscall.SIGHUP, syscall.SIGQUIT, syscall.SIGTERM, syscall.SIGINT)
      for {
          sig := <-signals
          logger.Infof("get signal %s", sig.String())
          switch sig {
          case syscall.SIGHUP:
              // reload()
          default:
              time.AfterFunc(time.Duration(survivalTimeout), func() {
                  logger.Warnf("app exit now by force...")
                  os.Exit(1)
              })
  
              // The program exits normally or timeout forcibly exits.
              fmt.Println("provider app exit now...")
              return
          }
      }
  }
  

Consumer

1. Set up the dubbo service you need to subscribe to at the beginning of the program startup. Make sure that the configuration file client.yml has been configured with the relevant information of the subscription service, and the service properties can be customized to override the configuration of the Provider's properties. Retain minimum configuration application and references verification point-to-point direct connection effect, no need to configure the registry.

var userProvider = new(pkg.UserProvider)

func init() {
    config.SetConsumerService(userProvider)
    hessian.RegisterPOJO(&pkg.User{})
}

application:
  organization: "dubbo.io"
  name: "UserInfoClient"
  module: "dubbo-go user-info client"
  version: "0.0.1"
  environment: "dev"
references:
  "UserProvider":
    registry: "demoZk"
    protocol: "dubbo"
    interface: "org.apache.dubbo.UserProvider"
    cluster: "failover"
    # this is necessary to enable direct-invoking.
    url: "dubbo://127.0.0.1:20000"
    methods:
      - name: "GetUser"
        retries: 3

If u wanna invoke a gRPC provider's service, pls change the url from “dubbo://127.0.0.1:20000” to “grpc://127.0.0.1:20000”.

2. Startup: Direct connection to the service to complete a service call

hessian.RegisterPOJO(&pkg.User{})
config.Load()
user := &pkg.User{}
err := userProvider.GetUser(context.TODO(), []interface{}{"A001"}, user)

How To Run

Refer to HOWTO.md under the root directory to run this sample.

1. Environment Configuration

Configure the environment variable to specify the configuration file path required for the service to load.

• go-server:

APP_LOG_CONF_FILE=direct/go-server/conf/log.yml;
CONF_PROVIDER_FILE_PATH=direct/go-server/conf/server.yml

• go-client:

APP_LOG_CONF_FILE=direct/go-client/conf/log.yml;
CONF_CONSUMER_FILE_PATH=direct/go-client/conf/client.yml

See dubbo-go/.../env.go

2. Start The Registry

This example uses ZooKeeper as the registry, so you can run the Docker ZooKeeper environment directly. See docker-compose.yml

3. Start The Provider

4. Start The Consumer

Refer to HOWTO.md under the root directory to run this sample.