Enhanced Dynamo DB and Integration Test Using Dynamo Local

Sun Oct 16 00:00:00 UTC 2022

AWS Released new Enhanced Dynamo Client Enhanced Dynamo Client which helps Java developers to easily Implement DAO Implementation without writing the mapping logic and AWS provides Downloadable DynamoDb which helps developers to do the Integration testing with Dynamo DB without connecting to the Cloud.

This post explains how to Implement a generic DynamoDBService Class using Enhanced Dynamo Client and Write Unit/Integration Test Cases using Downloadable DynamoDb

The full source code can be found under following repo

I have used following links and github repos to build this example

Prerequisite

  1. Java > 11

  2. Gradle > 5

Setting Enhanced Client in Gradle

To set up enhanced Client in Gradle following dependecies needs to be added

    implementation 'com.amazonaws:aws-java-sdk-dynamodb:1.11.434'
    implementation 'software.amazon.awssdk:dynamodb:2.17.28'
    implementation 'software.amazon.awssdk:dynamodb-enhanced:2.17.28'

Setting up DynamoDb Local

Aws documentation provides steps to setting up maven build but Gradle setting up is not provided by AWS and this library is not available central maven repo, so users needs to set up aws maven repo for setting DynamoDb Local

repositories {
    maven {
        name
         url "https://s3-us-west-2.amazonaws.com/dynamodb-local/release"
    }
}

following dependency will add DynamoDbLocal to the gradle project

testImplementation group: 'com.amazonaws', name: 'DynamoDBLocal', version: '1.11.119'

you can find more info about the set up in https://github.com/redskap/aws-dynamodb-java-example-local-testing/blob/master/README.md . As a part of test setup copy AwsDynamoDbLocalTestUtils and call AwsDynamoDbLocalTestUtils#initSqLite() during setup function of JUnit Test class

DynamoDb Domain POJO

This class is POJO representation of Dynamo DB schema, I have used lombok to avoid boiler plating of Getter and Setter methods, @DynamoDbBean represents dynamo db structure and @DynamoDbPartitionKey represents primary key id

@Data
@DynamoDbBean
public class Student {
    private String studentId;
    private String studentName;
    private String department;
    @DynamoDbPartitionKey
    @DynamoDbAttribute("studentId")
    public String getStudentId() {
        return studentId;
    }
}

DynamoDb Service Implementation

This class has full DAO implementation

  1. CreateTable

  2. Insert/Update Item based on partitions key

  3. Get Item by Id

DynamoDBService.java

Setting Up JUnit Test class

During the startup JUnit will spin up a local dynamo DB instance and following code shows how to establish DynamoClient connectivity to local instance

private static final String TABLE_NAME = "Student";
private static  DynamoDBProxyServer server;
private static final String port = "8000";
private static final String uri = "http://localhost:"+port;

 @BeforeEach
    public void setUpTest() throws Exception {
        'AwsDynamoDbLocalTestUtils copied from the github repo as explained earlier'
        AwsDynamoDbLocalTestUtils.initSqLite();
        'This line will spin up local instance on 8080 port'
        server = ServerRunner.createServerFromCommandLineArgs(
                new String[]{"-inMemory", "-port", port});
        server.start();
        client=DynamoDbClient.builder()
                .endpointOverride(URI.create(uri))
                .region(Region.AF_SOUTH_1)'Any region should work '
                .credentialsProvider(StaticCredentialsProvider.create(
                        AwsBasicCredentials.create("fakeMyKeyId","fakeSecretAccessKey")))
                .build();

    }