/dynamodb-local

DynamoDB Local project using Java | Example Codes

Primary LanguageJava

DynamoDB Local project using Java

(does not require aws account)

This project focuses on providing a complementary project, showcasing working with locally setup DynamoDB. Contains Java examples that use DynamoDB SDK to interact with the Database.

Recommended to first go through : DynamoDB Developer Guide

Steps to Recreate the project (from scratch)

Start the local DynamoDB server manually [1]

  1. Download the DynamoDB local JAR file

  2. Extract the tar.gz file :

    $ tar xvzf <dynamodb file>

  3. In the CLI, go to the directory where the files were extracted, and execute the following command:

    $ java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

    NOTE : This starts a local database with server running at the default port:8000 .

    Options available for starting DynamoDB [1] :

    • cors value — Enables support for cross-origin resource sharing (CORS) for JavaScript.

    • dbPath value — The directory where DynamoDB writes its database file.

    • delayTransientStatuses — Causes DynamoDB to introduce delays for certain operations.

    • help — Prints a usage summary and options.

    • inMemory — DynamoDB runs in memory instead of using a database file.

    • optimizeDbBeforeStartup — Optimizes the underlying database tables before starting DynamoDB on your computer.

    • port value — The port number that DynamoDB uses to communicate with your application.

Set the credentials for AWS [2]

  1. Setup some dummy credentials (required, as otherwise throws Error : Unable to load AWS credentials from any provider in the chain).

    The simplest method :

    • Open the default config file : ~/aws/credentials

    • Change the values in it to anything (like empty string here)

      [default]
aws_access_key_id=''
aws_secret_access_key=''

Create the Java project [3]

  1. Create a Maven project.

  2. Add the DynamoDB Maven repository to your application's Project Object Model (POM) file:

    <!--Dependency:-->
<dependencies>
    <dependency>
       <groupId>com.amazonaws</groupId>
       <artifactId>DynamoDBLocal</artifactId>
       <version>[1.11.86,2.0)</version>
    </dependency>
</dependencies>
<!--Custom repository:-->
<repositories>
    <repository>
       <id>dynamodb-local-oregon</id>
       <name>DynamoDB Local Release Repository</name>
       <url>https://s3-us-west-2.amazonaws.com/dynamodb-local/release</url>
    </repository>
</repositories>

    NOTE : choose the appropriate region-wise url for the repository (depending on the region for the downloaded DynamoDB in your system)

  3. Proceed with the Java programs.

Using the AWS CLI with Downloadable DynamoDB [4]

A preferable way to access and query your DB that is created is to use the aws cli. Install it in the terminal :

$ sudo pip install awscli

The AWS CLI can interact with DynamoDB (Downloadable Version) that runs on your computer. To enable this, add the following parameter to each command:

--endpoint-url http://localhost:8000

Here is an example that uses the AWS CLI to list the tables in a local database:

$ aws dynamodb list-tables --endpoint-url http://localhost:8000

If DynamoDB is using a port number other than the default (8000), modify the --endpoint-url value accordingly.

Few of the commonly used commands listed in the commands.sh file

References (further reading) :

[1]. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.html

[2]. https://stackoverflow.com/a/48187594/7550472

[3]. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Java.html

[4]. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Java.html

DISCLAIMER : this is not affiliated with Amazon Web Services (AWS) in any way other than for reference purposes.