DDSL plugin for Dropwizard

This is a plugin for Dropwizard that makes it really easy to enable Service Discovery to your services using DDSL.

Note about versions

Use version 2.0 if you are using Dropwizard 0.7.0 and version 1.0 if using Dropwizard 0.6.1

Example

Have a look at the Dropwizard example application.

How to use it in your own code

Maven dependency

You need to add the following dependency to your pom.xml:

    <dependency>
        <groupId>com.kjetland.ddsl</groupId>
        <artifactId>ddsl-dropwizard</artifactId>
        <version>2.0</version>
    </dependency>

Since DDSL and this plugin is hosted on my own maven repo here on github, you also have to add this to your pom:

    <repositories>
        <repository>
            <id>mbknor</id>
            <name>mbknor</name>
            <url>http://mbknor.github.com/m2repo/releases</url>
        </repository>
    </repositories>

Announce your service

This is how easy it is to enable Service Discovery announcing for your Dropwizard service

Add DdslConfig to your configuration class:

public class HelloWorldConfiguration extends Configuration {

    @JsonProperty
    @Valid
    @NotNull
    public DdslConfig ddslConfig;

}

Configure it like this in your yml-file:

ddslConfig:
  zookeeperHosts: localhost:2181
  serviceId:
    environment: test
    name: ddsl-example
    version: 1.0

Initialize it in your Service class:

    @Override
    public void run(HelloWorldConfiguration config, Environment environment) throws Exception {
        DdslService ddslService = new DdslService( config.ddslConfig);
        environment.lifecycle().addServerLifecycleListener( ddslService );
    }

When your app starts, it will resolve the url to your app and register it in DDSL. Now other apps can discover it using ddsl, or you can use ddslConfigWriter to automatically (re)configure an nginx reverse-proxy to start to send traffic to it. You can auto-scale.

Discover other services

This is how easy it is to use DDSL to discover a valid url to the service you want to connect to - with automatic load-balancing.

From code:

DdslServiceId otherService = new DdslServiceId( "test", "myService", "1.0 );
String url = ddslService.getBestLocationUrl(otherService);

If you want to make it configurable in your yml file, add this to your config file:

@JsonProperty
@Valid
public DdslServiceId otherService;

And configure it like this in yml:

otherService:
    environment: test
    name: ddsl-example-other
    version: 1.0