dynamodb - container with a local instance of dynamodb

This project can be used to build a docker image that contains an instance of the local DynamoDB source code. This image can then be used to serve as a DynamoDB provider without needing access to the cloud or internet. This can be useful for development or for execution in restricted environments.

Executing from docker hub

Pull the image

A built image is available from docker hub and accessed by:

docker pull brillozon/dynamodb

The local DynamoDB instance can be explored interactively using the shell at location: http://localhost:8000/shell.

Run the image

docker run -d -p 8000:8000 -v dynamodb\_code:/dynamodb\_code -v dynamodb\_data:/dynamodb\_data brillozon/dynamodb

This attaches the DynamoDB port to the host port 8000, and mounts the code and data volumes as named volumes on the local docker engine. This allows for persistence of tables and data as well as logs and configuration data over restarts of the local instance.

Development

After cloning this repository, you can use the docker-compose.yml file to manage and develop projects using a local copy of DynamoDB.

Build

Build an image:

docker-compose build

The image is based on the JRE 8 base image. An attempt was made to use the Alpine JRE 8 base image, but the DynamoDB code does not run correctly. This will require additional investigation. It is likely that additional packages need to be installed to the Alpine image.

The default command is set to use the default port and place the code and data into named volumes of the image.

Run

Start an instance:

docker-compose up -d

The compose file will mount a named volume for the code and another for the data used by the running instance. This allows the instance to be stopped and restarted while retaining the data from previous executions.

The default port (8000) will be forwarded to the default port on the host to provide access to the instance.

Stop the instance:

docker-compose down

Clients

Clients in several languages can be used to access this local dynamodb instance. Some of them are described here:

AWS CLI

Clients using the aws CLI should use the hostname and port where the instance is executing.

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

Python

From the AWS Documentation, a service resource reference can be created as:

dynamodb = boto3.resource('dynamodb',endpoint_url="http://localhost:8000")

From stack overflow, mechanisms for creating a client as well as service resource reference in Python to access the local DynamoDB instance include:

import boto3

# For a Boto3 client.
ddb = boto3.client('dynamodb', endpoint_url='http://localhost:8000')

# For a Boto3 service resource
ddb = boto3.resource('dynamodb', endpoint_url='http://localhost:8000')

An example taken from the AWS documentation is included in the file MoviesCreateTable.py

cd src
pip install -r requirements.txt
python MoviesCreateTable.py

You can find additional source and data files in the AWS DynamoDB documentation.

Javascript

From the AWS documentation, the Javascript client can be configured to access the local instance by updating the configuration before creating the DynamoDB object:

AWS.config.update({
  region: "us-west-2",
  endpoint: 'http://localhost:8000',
  // accessKeyId default can be used while using the downloadable version of DynamoDB. 
  // For security reasons, do not store AWS Credentials in your files. Use Amazon Cognito instead.
  accessKeyId: "fakeMyKeyId",
  // secretAccessKey default can be used while using the downloadable version of DynamoDB. 
  // For security reasons, do not store AWS Credentials in your files. Use Amazon Cognito instead.
  secretAccessKey: "fakeSecretAccessKey"
});

var dynamodb = new AWS.DynamoDB();