CRUD API (HTTP API + Lambda + DynamoDB)

Introduction

In this lesson, we will explore how to create a CRUD (Create, Read, Update, Delete) API using AWS Serverless technologies, specifically AWS Lambda and DynamoDB. This architecture allows developers to build scalable applications without managing servers.

Key Concepts

Step-by-Step Guide

Follow these steps to create a CRUD API using AWS Lambda and DynamoDB:

1. Set Up Your AWS Account: Sign up for AWS and log in.
2. Create a DynamoDB Table:
   Tip: Use a primary key that uniquely identifies each item.

   
                   // Example Table Creation
                   const AWS = require('aws-sdk');
                   const dynamoDB = new AWS.DynamoDB();
   
                   const params = {
                       TableName: 'Users',
                       KeySchema: [
                           { AttributeName: 'userId', KeyType: 'HASH' } // Partition key
                       ],
                       AttributeDefinitions: [
                           { AttributeName: 'userId', AttributeType: 'S' }
                       ],
                       ProvisionedThroughput: {
                           ReadCapacityUnits: 5,
                           WriteCapacityUnits: 5
                       }
                   };
   
                   dynamoDB.createTable(params, function(err, data) {
                       if (err) console.log(err);
                       else console.log("Table created:", data);
                   });
                   

3. Create Lambda Functions: Implement functions for each CRUD operation.
4. Set Up API Gateway: Create an HTTP API to trigger your Lambda functions.
5. Test Your API: Use tools like Postman to test all CRUD operations.

Lambda Function Example

        const AWS = require('aws-sdk');
        const dynamoDB = new AWS.DynamoDB.DocumentClient();

        exports.handler = async (event) => {
            const userId = event.pathParameters.userId;
            const params = {
                TableName: 'Users',
                Key: { userId }
            };

            try {
                const data = await dynamoDB.get(params).promise();
                return {
                    statusCode: 200,
                    body: JSON.stringify(data.Item)
                };
            } catch (error) {
                return {
                    statusCode: 500,
                    body: JSON.stringify({ error: error.message })
                };
            }
        };
        

Best Practices

• Use environment variables to store sensitive information.
• Implement API versioning to manage changes.
• Enable logging and monitoring for Lambda functions using CloudWatch.
• Optimize your DynamoDB queries to minimize costs.

FAQ