Simple API (Serverless + Lambda + LocalStack)

1. Set up local environment

Follow simple instructions to set up local environment.

Install LocalStack

pip install localstack

Install Serverless framework

npm install -g serverless

Install standalone binary for Serverless framework

curl -o- -L https://slss.io/install | bash

Install Serverless plugin for LocalStack

serverless plugin install -n serverless-localstack

Install python requirements plugin for LocalStack

serverless plugin install -n serverless-python-requirements

2. Local deployment

Start LocalStack

localstack start

You can verify that LocalStack is running by checking http://localhost:4566
You should get:

{"status": "running"}

Also, you can check the running services by checking https://0.0.0.0:4566/health
You should get:

{"features": {"initScripts": "initialized"}, "services": {"acm": "available", "apigateway": "available", "cloudformation": "available", "cloudwatch": "available", "config": "available", "dynamodb": "available", "dynamodbstreams": "available", "ec2": "available", "es": "available", "events": "available", "firehose": "available", "iam": "available", "kinesis": "available", "kms": "available", "lambda": "available", "logs": "available", "opensearch": "available", "redshift": "available", "resource-groups": "available", "resourcegroupstaggingapi": "available", "route53": "available", "route53resolver": "available", "s3": "available", "secretsmanager": "available", "ses": "available", "sns": "available", "sqs": "available", "ssm": "available", "stepfunctions": "available", "sts": "available", "support": "available", "swf": "available"}, "version": "0.14.0"}

Deploy your service locally

There are some ways to define configuration file for serverless. By serverless.yml, serverless.ts etc.

If you are using serverless.ts file, you have to install additional npm packages by running:

npm install @serverless/typescript

npm install --global ts-node

Deploy to serverless

serverless deploy --stage local

After the deployment you are going to get message from Serverless:

Service deployed to stack localstack-test-local

And also get information about endpoint and functions that you can use in the service.

endpoint: http://localhost:4566/restapis/{YOUR ID}/local/_user_request_

functions:
  get: localstack-tutorial-local-get
  post: localstack-tutorial-local-post

3. Local usage

• GET | /hello-world - get Hello World message.

$ curl -X GET "http://localhost:4566/restapis/{YOUR ID}/local/_user_request_/hello-world"

{
  "result": "Hello World"
}

• POST | /add - get sum of Hello World message.

curl -X POST "http://localhost:4566/restapis/{YOUR ID}/local/_user_request_/add" \
       -H 'Content-type: application/json' \
       -d '{
           "first": 1,
           "second": 2
       }'

{
  "result": 3
}