Amazon API Gateway HTTP API to AWS Simple Queue Service (SQS) to Lambda

This pattern creates an Amazon API Gateway HTTP API with a send route that send message to a SQS queue. The Amazon API Gateway HTTP API has basic CORS configured. Upon receiving message, SQS will trigger a Lambda function to process the message. The function will only print the message only. The function written in Python.

Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/apigw-http-sqs-lambda-cdk

Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the AWS Pricing page for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.

Requirements

Create an AWS account if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
AWS CLI installed and configured
Git Installed
AWS Cloud Development Kit (AWS CDK) installed
Python 3.8+ Installed

Deployment Instructions

Create a new directory, navigate to that directory in a terminal and clone the GitHub repository:
```
git clone https://github.com/aws-samples/serverless-patterns
```
Change directory to the pattern directory:
```
cd apigw-http-api-sqs-lambda-cdk
```
Create virtualenv
```
python3 -m venv .venv
```
Activate your virtualenv.
```
source .venv/bin/activate
```
Once the virtualenv is activated, you can install the required dependencies.
```
pip install -r requirements.txt
```
At this point you can now synthesize the CloudFormation template for this code.
```
cdk synth
```
Useful CDK commands
- cdk ls list all stacks in the app
- cdk synth emits the synthesized CloudFormation template
- cdk deploy deploy this stack to your default AWS account/region
- cdk diff compare deployed stack with current state
- cdk docs open CDK documentation
Deploy CDK stack
```
cdk deploy
```

How it works

The API Gateway handles the incoming API requests and send the $request.body.MessageBody as a message to SQS queue. A Lambda function will be trigger upon the message arraived.

Testing

Running following cURL command to agaist the HTTP API Endpoint

curl -XPOST https://${HTTP_API_ENDPOOINT}/send -d'{"MessageBody":"hello"}'

Expected result

<?xml version="1.0"?><SendMessageResponse xmlns="http://queue.amazonaws.com/doc/2012-11-05/">
    <SendMessageResult>
        <MessageId>xxxxxx</MessageId>
        <MD5OfMessageBody>xxxxxx</MD5OfMessageBody>
    </SendMessageResult>
    <ResponseMetadata>
        <RequestId>xxxx</RequestId>
    </ResponseMetadata>
</SendMessageResponse>