Fluent -style builder API support.

[chickenlj]

I am thinking of providing a fluent -style builder API built on ServiceConfig, ReferenceConfig, ...
It may work like this:

ApplicationConfig applicationConfig = ApplicationBuilder.name("demo").build();

ServiceConfig serviceConfig = ServiceBuilder.ref(ref).timeout(1000).build();
ReferenceConfig referenceConfig = ReferenceBuilder.interface("interface name").timeout(2000).build();

DubboBuilder dubboBuilder = DubboBuilder.application(applicationConfig).registry(registryConfig).protocol(protocol);

// To trigger the export/refer process, you can just start dubboBuilder
dubboBuilder.services(Arrays.asList(serviceConfig)).references(Arrays.asList(referenceConfig)).start();
// Or, you can export/refer one specific Service or Reference
dubboBuilder.export(serviceConfig);
dubboBuilder.refer(referenceConfig);

At present, one of the problems of using ServiceConfig and ReferenceConfig directly is that some application-level configurations need to be set to each ServiceConfig or ReferenceConfig, which is redundant, unnecessary and inconvenient for users

ApplicationConfig application = new ApplicationConfig();

ServiceConfig serviceConfig1 = new ServiceConfig();
serviceConfig1.setApplication(application);
serviceConfig1.export();

ServiceConfig serviceConfig2 = new ServiceConfig();
serviceConfig2.setApplication(application);
serviceConfig2.export();

[chickenlj]

ConfigManager can work as the basis for the Builder: https://github.com/apache/incubator-dubbo/blob/master/dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/context/ConfigManager.java

[kun-song]

Good idea!

[xxlv]

Cool,I love it

[Kiddinglife]

nice

[tswstarplanet]

I think the export and refer method of DubboBuilder can provider overload methods such as

DubboBuilder.export(ServiceConfig service,  ProviderConfig provider, RegistryConfig registry)
java
if users would like to refer specific config to a service or a reference. They can config by themselves.

[chickenlj]

DubboBuilder.export(ServiceConfig service, ProviderConfig provider, RegistryConfig registry)
java
if users would like to refer specific config to a service or a reference. They can config by themselves.

I would suggest providing the service-restricted configs using ServiceConfigBuilder:
ServiceConfigBuilder.provider(The ProviderConfig).registry(The RegistryConfig).build()

What do you think? @tswstarplanet

[chickenlj]

Is there anyone who's interested and want to give it a try?

[tswstarplanet]

Yes, it looks good. We should also limit reproduction of global configs, such as application.

[Bricks-Man]

I want to try this issue.And I will commit a pr after serveral days

[chickenlj]

Yes, it looks good. We should also limit reproduction of global configs, such as application.

Yes, the ConfigManager introduced in 2.7.0 can achieve that, but it may have some room for improvement.

[chickenlj]

@Bricks-Man Awesome, please let me know if you have any problem.

[chickenlj]

Further thought on this topic.

A unified entry like DubboBuilder.start() can help us with:

1. Application level rules. You may have noticed of some application level rules introduced in 2.7.0. The rules are fetched and watched inside each Service, I think it would be better if we can have an application level place to do that.
2. Adapting to microservice architecture. The microservice model is one microservice per process which is different from Dubbo's interface level service model. A unified entry would make the application level service discovery model more easily achieved.

[Bricks-Man]

@chickenlj I have finished this issue.Could you have time to do a review for it?Please tell me if you have any question.

[cvictory]

#3661