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Lambda Person Request DynamoDB

Description​

lambda-person-request-dynamodb-01.png

Prerequisites​

Start LocalStack via Docker Compose​

version: '3.8'

services:
  localstack:
    image: localstack/localstack
    container_name: localstack_main
    ports:
      - "4566-4599:4566-4599"
    environment:
      - SERVICES=sns,s3,sqs,dynamodb,ses,lambda,logs,stepfunctions
      - DYNAMODB_SHARE_DB=1
      - DEBUG=1
      - DATA_DIR=/tmp/localstack/data
      - DOCKER_HOST=unix:///var/run/docker.sock
    volumes:
      - "${LOCALSTACK_VOLUME_DIR:-./volume}:/var/lib/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"

Create DynamoDB Table​

awslocal dynamodb create-table \
    --table-name person \
    --key-schema AttributeName=id,KeyType=HASH \
    --attribute-definitions AttributeName=id,AttributeType=N \
    --billing-mode PAY_PER_REQUEST

Prepare Lambda Code​

Source Code:
https://github.com/ZbCiok/zjc-examples/tree/main/aws/aws/lambda/lambda-person-request-dynamodb

  • Project Structure​

├── cmds.txt
├── pom.xml
├── README.md
└── src
    └── main
        ├── java
        │   └── v2
        │       └── dynamodb
        │           ├── PersonRequest.java
        │           ├── PersonResponse.java
        │           └── SavePersonHandler.java
        └── resources

  • PersonRequest.java​

package v2.dynamodb;

import lombok.NoArgsConstructor;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;

@NoArgsConstructor
@DynamoDbBean
public class PersonRequest {

    private int id;
    private String firstName;
    private String lastName;
    private int age;
    private String address;

    @DynamoDbPartitionKey
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "PersonRequest{" +
                "address='" + address + '\'' +
                '}';
    }
}

  • PersonResponse.java​

package v2.dynamodb;

import lombok.NoArgsConstructor;


@NoArgsConstructor
public class PersonResponse {
    private String message;

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }


    @Override
    public String toString() {
        return "PersonResponse{" +
                "message='" + message + '\'' +
                '}';
    }
}

  • SavePersonHandler​

package v2.dynamodb;

import java.text.ParseException;
import java.net.URI;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import lombok.extern.java.Log;
import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;

@Log
public class SavePersonHandler  implements RequestHandler<PersonRequest, PersonResponse> {

  private static final String ACCESS_KEY = "test";
  private static final String SECRET_KEY = "test";
  private static String TABLE_NAME = "person";
  private static AwsCredentialsProvider credentials = StaticCredentialsProvider.create(
      AwsBasicCredentials.create(ACCESS_KEY, SECRET_KEY));

  private static Region region = Region.US_EAST_1;

  private static DynamoDbClient dynamoDbClient = DynamoDbClient.builder()
      .region(region)
      .credentialsProvider(credentials)
      .endpointOverride(URI.create("https://localhost.localstack.cloud:4566"))
      .build();

// -----

  public PersonResponse handleRequest(PersonRequest personRequest, Context context) {
    log.info("Start handleRequest >>>");

    String personId1 = "300012356";
      try {
          addEntryToDynamoDB(personId1);
      } catch (Exception e) {
          log.info("Exception handleRequest >>> " + e.getMessage());
      }

    PersonResponse personResponse = new PersonResponse();
    personResponse.setMessage("Success >>> Add Entry Successfully!!!");
    return personResponse;
  }

  private static void addEntryToDynamoDB(String personID) throws ParseException {
    try {
      DynamoDbEnhancedClient enhancedClient = DynamoDbEnhancedClient.builder()
              .dynamoDbClient(dynamoDbClient)
              .build();

      // create the person object
      PersonRequest person = new PersonRequest();
      person.setId(Integer.parseInt(personID));
      person.setFirstName("Doe");
      person.setLastName("John");
      person.setAge(Integer.parseInt("19790101"));
      person.setAddress("Address 01");

      // use the enhanced client to interact with the table
      DynamoDbTable<PersonRequest> table = enhancedClient.table(TABLE_NAME,
              TableSchema.fromBean(PersonRequest.class));
      table.putItem(person);

      log.info(">>> Add Entry successfully");
    } catch (DynamoDbException exception) {
      log.info(">>> Add Entry an error occurred: " + exception.getMessage());
    }
  }

}

  • Deploy Lambda Function​

    • mvn clean package​

    • Create Function​

    awslocal lambda create-function \
        --function-name example-lambda \
        --runtime java21 \
        --handler v2.dynamodb.SavePersonHandler::handleRequest \
        --zip-file fileb://lambda-person-request-dynamodb-1.0-SNAPSHOT.jar \
        --role arn:aws:iam::000000000000:role/lambda-role

Test Lambda​

awslocal lambda invoke --function-name example-lambda \
    --cli-binary-format raw-in-base64-out \
    --payload '{ "name": "John Doe", "question": "How are you?" }' output.txt

Output​

  • See Docker Log
  • See DynamoDB table: 
     awslocal dynamodb query \
         --table-name person \
         --key-condition-expression "id = :id" \
         --expression-attribute-values  '{":id":{"N":"300012356"}}'
{
    "Items": [
        {
            "firstName": {
                "S": "John"
            },
            "lastName": {
                "S": "Doe"
            },
            "address": {
                "S": "Address01"
            },
            "id": {
                "N": "1"
            },
            "age": {
                "N": "26"
            }
        }
    ],
    "Count": 1,
    "ScannedCount": 1,
    "ConsumedCapacity": null
}