A basic example of a Sinatra application.

Using AWS Lambda Adapter, You can package this web application into Docker image, push to ECR, and deploy to Lambda, ECS/EKS, or EC2.

The application can be deployed in an AWS account using the Serverless Application Model. The template.yaml file in the root folder contains the application definition.

The top level folder is a typical AWS SAM project. The app directory is a Sinatra application with a Dockerfile.

FROM public.ecr.aws/docker/library/ruby:3.3
COPY --from=public.ecr.aws/awsguru/aws-lambda-adapter:1.0.1 /lambda-adapter /opt/extensions/lambda-adapter
WORKDIR /var/task
COPY Gemfile Gemfile.lock ./
RUN bundle install
COPY . .
CMD ["bundle", "exec", "ruby", "app.rb", "-o", "0.0.0.0", "-p", "8080"]

The following tools should be installed and configured.

• AWS CLI
• SAM CLI
• Docker
• Ruby

Navigate to the sample's folder and use the SAM CLI to build a container image:

$ sam build

This command compiles the application and prepares a deployment package in the .aws-sam sub-directory.

To deploy the application in your AWS account, you can use the SAM CLI's guided deployment process and follow the instructions on the screen:

$ sam deploy --guided

Please take note of the container image name. Once the deployment is completed, the SAM CLI will print out the stack's outputs, including the new application URL. You can use curl or a web browser to make a call to the URL.

NOTE: This SAM does not use Amazon API Gateway, but uses AWS Lambda function URLs to create HTTP endpoints.

...
CloudFormation outputs from deployed stack
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Outputs
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Key                 SinatraFunction1
Description         Function URL endpoint on AWS Lambda
Value               https://xxxxxxxxxxxxxxxxxxxxxxxxx.lambda-url.REGION.on.aws/
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------...

$ curl https://xxxxxxxxxxxxxxxxxxxxxxxxx.lambda-url.REGION.on.aws/

We can run the same docker image locally, so that we know it can be deployed to ECS Fargate and EKS EC2 without code changes.

$ docker run -it --rm -p 8080:8080 {ECR Image}

Use curl from another session to checking that the Docker container is working.

$ curl localhost:8080/
#=> Hello! I am <b>Sinatra</b>.