An AWS Lambda custom runtime to enable Java 18 support on a minimalistic JRE, which only includes the Java modules required by the application. This is the example repository for the Build a custom Java runtime for AWS Lambda blog post.

1. Download the preferred Java version and take advantage of jdeps, jlink and Class Data sharing to create a minified and optimized Java runtime based on the application code (function.jar).
2. Create a bootstrap file with optimized starting instructions for the application.
3. Package the application code, the optimized Java runtime and the bootstrap file as a zip file.
4. Deploy the runtime, including the app, to AWS Lambda e.g. via the AWS Cloud Development Kit (CDK)

1. Download or clone the repository.

2. install prerequisite software:

   1. Install AWS CDK
   2. Install Docker

3. Build and package the AWS Lambda function and create the AWS Lambda custom runtime using Docker:

./build.sh

4. Provision the AWS infrastructure (Amazon API Gateway, AWS Lambda and Amazon DynamoDB) using AWS CDK:

./provision-infrastructure.sh

The API Gateway endpoint URL is displayed in the output and saved in the file infrastructure/target/outputs.json. The contents are similar to:

{
  "LambdaCustomRuntimeMinimalJRE18InfrastructureStack": {
    "apiendpoint": "https://<API_ID>.execute-api.<AWS_REGION>.amazonaws.com/prod/"
  }
}

First, install prerequisites:

1. Install jq and Artillery Core
2. Run the following script from the projects root directory:

artillery run -t $(cat infrastructure/target/outputs.json | jq -r '.LambdaCustomRuntimeMinimalJRE18InfrastructureStack.apiendpoint') -v '{ "url": "/custom-runtime" }' infrastructure/loadtest.yml

1. Navigate to Amazon CloudWatch Logs Insights.
2. Select the log groups /aws/lambda/custom-runtime-java-18 from the drop-down list
3. Copy the following query and choose Run query:

 filter @type = "REPORT"
    | parse @log /\d+:\/aws\/lambda\/(?<function>.*)/
    | stats
    count(*) as invocations,
    pct(@duration+coalesce(@initDuration,0), 0) as p0,
    pct(@duration+coalesce(@initDuration,0), 25) as p25,
    pct(@duration+coalesce(@initDuration,0), 50) as p50,
    pct(@duration+coalesce(@initDuration,0), 75) as p75,
    pct(@duration+coalesce(@initDuration,0), 90) as p90,
    pct(@duration+coalesce(@initDuration,0), 95) as p95,
    pct(@duration+coalesce(@initDuration,0), 99) as p99,
    pct(@duration+coalesce(@initDuration,0), 100) as p100
    group by function, ispresent(@initDuration) as coldstart
    | sort by coldstart, function

You see results similar to:

For cold-starts only you will see results similar to:

See CONTRIBUTING for more information.

This library is licensed under the MIT-0 License. See the LICENSE file.