Serverless Rust Microservice for Score Percentile

This project aims to develop a serverless function on AWS Lambda utilizing Rust and Cargo Lambda, integrating with a database - AWS DynamoDB. This project focuses on leveraging AWS Lambda's capabilities, integrating with AWS API Gateway, and utilizing DynamoDB. The objective is to create a Lambda function that can calculate the percentile rank of a given score among all scores.

Goals

• Create a Rust AWS Lambda function (or app runner)
• Implement a simple service
• Connect to a database

Steps

Step 1: Initialize Rust Project

• Begin by initializing your Cargo Lambda project using the command cargo lambda new <YOUR-PROJECT-NAME>.
• Modify the Cargo.toml and src/main.rs file according to your design and requirements.
• Navigate to the project directory, locally test the functionality by running the command cargo lambda watch .

Step 2: AWS Setup

• Navigate to the AWS IAM Management Console to create a new IAM User for credential management.
• Attach policies LambdaFullAccess and IAMFullAccess.
• Under Security Sredentials section, generate an access key for API access. Make sure the key is safely stored and not lost.
• Set up your environment variables so that cargo lambda knows which AWS account and region to deploy to.

export AWS_ACCESS_KEY_ID="your_access_key_here"
export AWS_SECRET_ACCESS_KEY="your_secret_key_here"
export AWS_DEFAULT_REGION="your_preferred_region_here"

• Build the project by running cargo lambda build --release.
• Deploy the project by running cargo lambda deploy.
• Go to AWS console and enter AWS Lambda, navigate into your lambda function, then under Configuration, click Permission, then click the link under your Role name.
• In the new tab, attach policies AmazonDynamoDBFullAccess and AWSLambdaBasicExecutionRole to your role.

Step 3: Connection to DynamoDB and API Configuration

• Navigate to the AWS console to establish a DynamoDB table. Click on the Items tab, then click on Create item.
• Choose a name for your table. The name must align with that in your main.rs file.
• Partition key: This is the primary key of your table.
• 'Explore table items' -> 'Create item' to insert the item.
• Once the table is ready, proceed to link your Lambda function with AWS API Gateway.
• Initiate a new API setup, opting for the default REST API option, and then create a new resource for your API's endpoint.
• For the created resource, implement an ANY method and associate it with your Lambda function.
• Launch your API by creating a new deployment stage.
• Click deploy, find stages and find your invoke URL.
• You can test your API gateway using curl request:

curl -X POST https://5eho0mtuof.execute-api.us-east-1.amazonaws.com/test/StudentScores -H "Content-Type: application/json" -d '{"score": 99}'

Step 4: Gitlab Deploy

• After the success of test, set your AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_REGION to gitlab Settings -> CI/CD -> Variables.
• Use .gitlab-ci.yml and makefile to enable auto build, test, and deploy of the lambda function.

Screenshots

• Curl request

• DynamoDB

• Lambda