Example

This example is designed for a concept mobile application called Skip the Line, which allows user to pre-order takeaway coffee while they are in transit. Just as the train pulls into the station, the user can order a coffee and pick it up on the way past the coffee shop.

This example uses an Amazon API Gateway endpoint to allow the mobile app to add and manage orders. There are four AWS Lambda functions deployed behind the gateway endpoint, they are used to execute CRUD (create, read, update, delete) operations against an Amazon DynamoDB order table.

The Amazon DynamoDB table is partitioned on an accountid attribute and also includes a sort key on the vendorid attribute, together they form the primary key. The example also demonstrates using Python to put, update, get and delete items in Amazon DynamoDB.

By integrating an API Gateway endpoint with AWS Lambda functions and an Amazon DynamoDB table you can build basic microservice architecture that is scalable, highly available and cost effective. This is a standard pattern for applications that require a CRUD backend.

The example also includes a Python Lambda layer with the aws_embedded_metrics module. The aws_embedded_metrics is used to capture order details as additional metrics which can be viewed using Amazon CloudWatch Log Insights.

Setup

You will need to download and install Node.js before you can start using the AWS Cloud Development Kit.

This example is developed using the AWS CDK and Typescript, so you will need to install both Typescript and the CDK using the following commands

npm install -g typescript
npm install -g aws-cdk@latest

Since this CDK project uses 'Assests', you might need to run the following command to provision resources the AWS CDK will need to perform the deployment.

cdk bootstrap

The testing scripts can be executed using Jupyter Notebook. There are a few methods for installing Jupyter Notebooks. These instructions will help you get to started with JupyterLab installation.

You can also install Jupyter Notebooks as part of Anaconda installation.

To download this example, you will need to install Git. After installing git follow these instructions to learn how to clone the repository.

After the repository has been cloned set the command prompt path to the cloned directory and run the following command to install the project dependencies.

npm install

cdk synth executes the application which translates the Typescript code into an AWS CloudFormation template.

cdk synth

After the synth command has generated the template use the cdk deploy command to deploy the template to AWS CloudFormation and build the stack. You will be prompted to confirm the deployment with y/n.

cdk deploy

Run the Example

Open the Jupyter Notebook in the jupyter_notebook directory follow the instructions.

Cleanup

From the command prompt execute the following command: cdk destroy

Deployed Resources

Identifier	Service	Type
apigw_lambda_dynamodb	DynamoDB	Table
account/ApigwL-Order-FWxkXGJAl84t	ApiGateway	Account
ApigwLambdaDynamodbStack-OrderApiCloudWatchRoleB19-O3GSF61CEV4Q	IAM	Role
restapis/so9wvpacfj	ApiGateway	RestApi
embeded_metrics	Lambda	LayerVersion
apigw_Lambda_dynamodb_delete_item	Lambda	Function
apigw_lambda_dynamodb_delete	IAM	Role
apigw_Lambda_dynamodb_get_item	Lambda	Function
apigw_lambda_dynamodb_get	IAM	Role
apigw_Lambda_dynamodb_put_item	Lambda	Function
apigw_lambda_dynamodb_put	IAM	Role
apigw_Lambda_dynamodb_update_item	Lambda	Function
apigw_lambda_dynamodb_update	IAM	Role