CloudQuest - Deploying RESTful APIs

Problem: Frontend, DB is ready, but need a method to connect

Solution: API Gateway as front door of the app+ Lambda to process data

How to link lambda with API Gateway?

Lambda Proxy Integration, a feature of API Gateway, allows client to call a single lambda function in the backend,which can call other lambda functions or AWS services or resources

Amazon API Gateway Stages

Amazon API Gateway - Versioning Deployment Strategies Overview

Microservices

Summary:

1. Create Lambda function

2. Create API Gateway - RESTful API

Important Notes:

1. Lambda Test event choose - API Gateway AWS Proxy template

2. Serialize python JSON with response_payload function,

````

response = response_payload(err, response_body)

return response

'''

In Lambda proxy integration, API Gateway sends the entire request as input to a backend Lambda function.

API Gateway then transforms the Lambda function output to a frontend HTTP response.

Output Format: https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format

'''

def response_payload(err, res=None):

return {

'statusCode': '400' if err else '200',

'body': err if err else json.dumps(res),

'headers': {

'Content-Type': 'application/json',

},

}

```

1. Step for API Gateway + Lambda

3.1) Create Resources, with name pets

3.2) Create Method, check lambda proxy integration (Send the request to your Lambda function as a structured event), and select lambda

3.3) To create /{id} path, click on resources route /pets, and click ‘Create resource’, then Resource name == {id}

3.4) On method, select same method as 3.2

3.5) Go to test tab, add 1 as id and test it.

1. On Lambda Test event, you configure resource and pathParameters key. I.e.

"resource": "/pets/{id}"

"pathParameters": {

"id": 1

}

Then in Lambda, it’s filtered like