This example implements a very simple Hello World API using AWS Lambda and AWS API Gateway.

The API will respond to GET requests always returning:

{"message":"Hello World"}

The goal of this exercise is to learn how to write a very simple Lambda, test it locally and deploy it on AWS.

With aws-sam-local you can test if your template.yaml file is valid by typing

sam validate

With aws-sam-local installed and your shell in this project folder (lessons/01-simple-hello-world-api/), run:

sam local invoke HelloWorldApi -e sample-event.json

To run it as a local API, i.e. run it using a local API Gateway.

sam local start-api

You can deploy on your AWS account with the following commands using AWS cli:

export BUCKET=your-unique-bucket-name
export STACK_NAME=simple-hello-world

sam package --template-file template.yaml --s3-bucket $BUCKET --output-template-file packaged-template.yml

sam deploy --template-file packaged-template.yml --stack-name $STACK_NAME --capabilities CAPABILITY_IAM

Be sure to replace the value of BUCKET with your own unique bucket name