Amazon API Gateway, AWS Lambda and Amazon DynamoDB with Lambda SnapStart for Java

Requirements

• 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
• Maven
• CURL

Deployment Instructions

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-snapstart
   
3. Build the function

   sam build
   
4. Deploy the infrastructure

   sam deploy --stack-name unicorn-store --guided
   

Testing

To test the Lambda function you can POST a unicorn JSON payload to the '/unicorns' endpoint.

curl --location --request POST $(aws cloudformation describe-stacks --stack-name unicorn-store --query "Stacks[0].Outputs[?OutputKey=='UnicornEndpoint'].OutputValue" --output text)'/unicorns' \
--header 'Content-Type: application/json' \
--data-raw '{
"name": "Something",
"age": "Older",
"type": "Animal",
"size": "Very big"
}' | jq

Measuring the results

You can use the following AWS CloudWatch Insights query to measure the duration your SnapStart Lambda function.

filter @message like "REPORT"
| filter @message not like "RESTORE_REPORT"
| parse @message /Restore Duration: (?<@restore_duration_ms>[0-9\.]+)/
| parse @message /	Duration: (?<@invoke_duration_ms>[0-9\.]+)/
| fields
  greatest(@restore_duration_ms, 0) as restore_duration_ms,
  greatest(@invoke_duration_ms, 0) as invoke_duration_ms
| fields
  restore_duration_ms + invoke_duration_ms as total_invoke_ms
| stat
  pct(total_invoke_ms, 50) as total_invoke_ms_p50,
  pct(total_invoke_ms, 99) as total_invoke_ms_p99,
  pct(total_invoke_ms, 99.9) as total_invoke_ms_p99.9