This pattern shows how to build a durable, in-memory, cluster-enabled database service and integrate it with AWS Lambda. Lambda functions use REST API calls to access the data and configuration from the MemoryDB.

Learn more about this pattern at Serverless Land Patterns: https://github.com/aws-samples/serverless-patterns/tree/main/apigw-lambda-memorydb

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the AWS Pricing page for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

• Create an AWS account if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
• AWS CLI installed and configured
• Git Installed
• AWS Serverless Application Model (AWS SAM) installed

1. Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:

   git clone https://github.com/aws-samples/serverless-patterns
   

2. Change directory to the pattern directory:

   cd apigw-lambda-memorydb
   

3. From the command line, use AWS SAM to deploy the AWS resources for the pattern as specified in the template.yml file:

   sam deploy --guided
   

4. During the prompts:

   • Enter a stack name
   • Enter the desired AWS Region
   • Allow SAM CLI to create IAM roles with the required permissions.

   Once you have run sam deploy --guided mode once and saved arguments to a configuration file (samconfig.toml), you can use sam deploy in future to use these defaults.

5. Note the outputs from the SAM deployment process. These contain the resource names and/or ARNs which are used for testing.

The sam template creates the MemoryDB cluster, API Gateway REST API with the relevant API methods, and the AWS Lambda functions.

• The API Gateway endpoint is publically accessible
• You call the relevant API method passing in the appropriate data
• The API method defined in the API Gateway will pass the request on to an AWS Lambda function set up for proxy integration
• The AWS Lambda function has the least privilege permissions configured
• The AWS Lambda function uses the cluster endpoint to interact with the MemoryDB

Once the application is deployed, retrieve the API Gateway endpoint value from CloudFormation Outputs. Either use the console or call the endpoint from Postman.

• POST API sample payload

{
   "key": "myKey",
   "field": "test",
   "value": "something"
}

• GET API sample request

https://<API Gateway Endpoint>?key=test&field=new

1. Delete the stack

   sam delete --stack-name STACK_NAME

2. Confirm the stack has been deleted

   aws cloudformation list-stacks --query "StackSummaries[?contains(StackName,'STACK_NAME')].StackStatus"

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