Dapr SDK for Java

This is the Dapr SDK for Java, including the following features:

• PubSub
• Service Invocation
• Binding
• State Store
• Actors

Getting Started

Pre-Requisites

• Java IDE installed:
  • IntelliJ
  • Eclipse
  • Apache NetBeans
  • Visual Studio Code
  • Any other IDE for Java that you prefer.
• Install one of the following build tools for Java:
  • Maven 3.x
  • Gradle 6.x
• If needed, install the corresponding plugin for the build tool in your IDE, for example:
  • Maven in IntelliJ
  • Gradle in IntelliJ
  • Maven in Eclipse with m2e
  • Gradle in Eclipse with Buildship
• An existing Java Maven or Gradle project. You may also start a new project via one of the options below:
  • New Maven project in IntelliJ
  • Maven in 5 minutes

Importing Dapr's Java SDK

For a Maven project, add the following to your pom.xml file:

<project>
  ...
  <distributionManagement>
   ...
    <!-- BEGIN: Dapr's repositories -->
    <snapshotRepository>
      <id>ossrh</id>
      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
    </snapshotRepository>
    <repository>
      <id>ossrh</id>
      <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
    </repository>
    <!-- END: Dapr's repositories -->
   ...
  </distributionManagement>
  ...
  <dependencyManagement>
      <dependencies>
        ...
         <!-- Dapr's core SDK with all features, except Actors. -->
        <dependency>
          <groupId>io.dapr</groupId>
          <artifactId>dapr-sdk</artifactId>
          <version>0.2.0-beta-2</version>
        </dependency>
        <!-- Dapr's SDK for Actors (optional). -->
        <dependency>
          <groupId>io.dapr</groupId>
          <artifactId>dapr-sdk-actors</artifactId>
          <version>0.2.0-beta-2</version>
        </dependency>
        ...
      </dependencies>
  </dependencyManagement>
</project>

Running the examples

Clone this repository including the submodules:

git clone https://github.com/dapr/java-sdk.git

Then head over to build the Maven (Apache Maven version 3.x) project:

# make sure you are in the `java-sdk` directory.
mvn clean install

Try the following examples to learn more about Dapr's Java SDK:

• Invoking a Http service
• Invoking a Grpc service
• State management
• PubSub with subscriber over Http
• Binding with input over Http
• Actors over Http

Debug Java application or Dapr's Java SDK

If you have a Java application or an issue on this SDK that needs to be debugged, run Dapr using a dummy command and start the application from your IDE (IntelliJ, for example). For Linux and MacOS:

dapr run --app-id testapp --app-port 3000 --port 3500 --grpc-port 5001 -- cat

For Windows:

dapr run --app-id testapp --app-port 3000 --port 3500 --grpc-port 5001 -- waitfor FOREVER

When running your Java application from IDE, make sure the following environment variables are set, so the Java SDK knows how to connect to Dapr's sidecar:

DAPR_HTTP_PORT=3500
DAPR_GRPC_PORT=5001

Now you can go to your IDE (like IntelliJ, for example) and debug your Java application, using port 3500 to call Dapr while also listening to port 3000 to expose Dapr's callback endpoint.

Calls to Dapr's APIs on http://127.0.0.1:3500/* should work now and trigger breakpoints in your code.

If your application needs to subscribe to topics or register Actors in Dapr, for example, then start debugging your app first and run dapr with dummy command last.

If using Visual Studio Code, also consider this solution as well.

Creating and publishing the artifacts to Nexus Repository

In case you need to publish Dapr's SDK to a private Nexus repo, run the command below from the project's root directory:

mvn package
mvn deploy:deploy-file -DgeneratePom=false -DrepositoryId=nexus -Durl=http://localhost:8081/repository/maven-releases -DpomFile=pom.xml -Dfile=target/dapr-sdk-0.2.0.jar

For more documentation reference :

https://maven.apache.org/plugins/maven-deploy-plugin

https://help.sonatype.com/repomanager3/user-interface/uploading-components

Development

Maven Module version management

When releasing a new version of this SDK you must increase the version of all modules and pom files, so run the following commands:

mvn versions:set -DnewVersion="0.1.0-preview02"
mvn versions:commit