[Java] JUnit with DynamoDBLocal

先設定 build.gradle：

// build.gradle
repositories {
    maven {
        // dynamodb local url
        url 'https://s3-us-west-2.amazonaws.com/dynamodb-local/release'
    }

    testCompile (
        'org.junit.jupiter:junit-jupiter-api:5.2.0',
        'com.amazonaws:DynamoDBLocal:1.11.119'
    )

    testRuntime (
        // junit5
        'org.junit.jupiter:junit-jupiter-engine:5.2.0',
        // dynamodb local
        'com.almworks.sqlite4java:libsqlite4java-linux-i386:1.0.392',
        'com.almworks.sqlite4java:libsqlite4java-osx:1.0.392'
    )
}
// link native sqlite4java
task copyNativeDeps(type: Copy) {
    from (configurations.testCompile) {
        include '*.dylib'
        include '*.so'
        include '*.dll'
    }
    into 'build/libs'
}

test {
    useJUnitPlatform()
    dependsOn copyNativeDeps
    doFirst {
        // setup sqlite4java path
        systemProperty 'java.library.path', 'build/libs'
    }
    testLogging {
        showStandardStreams = true
    }
}

接下來就是測試：

package example;

import java.util.ArrayList;
import java.util.List;

import org.junit.jupiter.api.Test;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.local.embedded.DynamoDBEmbedded;
import com.amazonaws.services.dynamodbv2.model.AttributeDefinition;
import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;

public class DynamoDBLocalTest {

    @Test
    public void createTable() throws Exception {
        AmazonDynamoDB client = DynamoDBEmbedded.create().amazonDynamoDB();
        DynamoDB dynamodb = new DynamoDB(client);
        String tableName = "Employee";

        List keySchema = new ArrayList();
        keySchema.add(new KeySchemaElement().withAttributeName("Name").withKeyType(KeyType.HASH));

        List attributeDefinitions = new ArrayList();
        attributeDefinitions.add(new AttributeDefinition().withAttributeName("Name").withAttributeType("S"));

        CreateTableRequest request = new CreateTableRequest().withTableName(tableName).withKeySchema(keySchema)
                .withProvisionedThroughput(
                        new ProvisionedThroughput().withReadCapacityUnits(1L).withWriteCapacityUnits(1L))
                .withAttributeDefinitions(attributeDefinitions);

        System.out.println("Issuing CreateTable request for " + tableName);
        Table table = dynamodb.createTable(request);
        System.out.println("Waiting for " + tableName + " to be created...this may take a while...");
        table.waitForActive();

        System.out.println(dynamodb.getTable(tableName).describe());
    }

}

參考資料：

• AWS文件: 设置 DynamoDB Local
• StackOverflow: Run Dynamodb local as part of a Gradle Java project
• AWS文件: 使用适用于 Java 的 AWS 开发工具包创建示例表和上传数据

系列：

• [Java] AWS Lambda 入門
• [Java] AWS Lambda + DynamoDB
• AWS Lambda + API Gateway
• [Java] JAX-RS on AWS Lambda
• [Java] JUnit with DynamoDBLocal

[Java] AWS Lambda + DynamoDB

承上文 [Java] AWS Lambda 入門， 這次添加存取 DynamoDB。

首先建立一個 DynamoDB 表單 "Employee"，同時建立一筆資料。

接下來進入 IAM 建立一個 Role，這裡直接選擇 "AWS service"， 在 "Choose the service that will use this role" 選擇 "Lambda"， 然後就可以點擊按鈕 "Next: Permissions"；
在 "Attach permissions policies" 裡面， 勾選 "AmazonDynamoDBFullAccess","AWSLambdaDynamoDBExecutionRole"， 然後點擊按鈕 "Next: Review"；
輸入 Role name，就可以建立一個 Role 了。

接下來回到之前建立的 Lambda，往下拉到 "Execution role"，選取剛剛建立的 Role 就成功了。

可以參考官方文件用 node 簡單測試一下，

• AWS SDL for JavaScript: Getting an Item
• AWSJavaScriptSDK

// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region 
AWS.config.update({region: 'ap-northeast-1'});

exports.handler = (event, context, callback) => {
  // Create the DynamoDB service object
  ddb = new AWS.DynamoDB({apiVersion: '2012-10-08'});

  var params = {
    TableName: 'Employee',
    Key: {
      'EmpId' : {S: '1000'}
    }
    //, ProjectionExpression: 'EmpId'
  };

  // Call DynamoDB to read the item from the table
  ddb.getItem(params, function(err, data) {
    if (err) {
      console.log("Error", err);
    } else {
      console.log("Success", data.Item);
      callback(null, data);
    }
  });
};

回到之前的 Java Project，修改一下：

package example;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

public class Hello implements RequestHandler {
    @Override
    public String handleRequest(Integer input, Context context) {
        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();
        DynamoDB dynamoDB = new DynamoDB(client);
        Table table = dynamoDB.getTable("Employee");
        Item item = table.getItem("EmpId", "10000");
        System.out.println(item.toJSONPretty());
        return item.toJSON();
    }
}

另外 Lambda 也提供直接轉換物件的方式，我們不用再去處理 Json 映射物件的問題。

package example;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBHashKey;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

import lombok.Data;

public class Hello implements RequestHandler {
    @Override
    public String handleRequest(Integer input, Context context) {
        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();
        DynamoDBMapper dynamodbMapper = new DynamoDBMapper(client);
        Employee result = dynamodbMapper.load(Employee.class, "10000");
        System.out.println(result);
        return result.toString();
    }

    @Data
    @DynamoDBTable(tableName = "Employee")
    class Employee {
        @DynamoDBHashKey(attributeName = "EmpId")
        private String id;
        @DynamoDBAttribute(attributeName = "Name")
        private String name;
    }
}

系列：

• [Java] AWS Lambda 入門
• [Java] AWS Lambda + DynamoDB
• AWS Lambda + API Gateway
• [Java] JAX-RS on AWS Lambda
• [Java] JUnit with DynamoDBLocal