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Retool Inventory Management System: Building a Serverless App with Retool, AWS, and EDA (P1)

Nhan Hoang
October 14, 2024
20 min read
Retool Inventory Management System: Building a Serverless App with Retool, AWS, and EDA (P1)

Building scalable internal tools becomes easier with Retool, AWS, and Event-Driven Architecture (EDA). This blog introduces RetoolerStock, a serverless inventory management system that automates tasks like stock updates and restocking alerts using AWS services, ensuring efficiency and scalability.

Building Scalable Internal Tools with Retool: Overcoming Common Challenges

As a developer at Retoolers.io, I’ve had the chances to working on range of projects using Retool. In this journey, I’ve come across several challenges and trends that frequently surface when developing internal tools.

The Growing Demand for Internal Tools

One of the most noticeable trends is the the elevated demand for internal tools. What often begins as a simple solution can quickly evolve into a complex system that requires rapid development and a robust architecture. As these projects expand, the teams behind them also grow, leading to a crucial question: How can we ensure that everyone stays aligned, especially when different projects utilize various technologies?

Embracing a Consistent Tech Stack

To tackle these challenges, I recognized the need for a consistent tech stack centered around Retool. Enter serverless architecture—an ideal solution for building scalable and efficient internal tools. AWS offers a suite of serverless services that can seamlessly integrate with Retool, including Step Functions, which are increasingly user-friendly for low-code developers.

However, even with the benefits of serverless computing, complexity can still emerge if the system isn’t designed properly. This is where Event-Driven Architecture (EDA) becomes a game-changer, allowing us to manage these complexities as our projects scale.

Introducing RetoolerStock: An Inventory Management System

Inventory Management

In this blog series, we’ll be building an application called RetoolerStock—a serverless, event-driven inventory management system tailored for small warehouses or retail businesses. Each post will guide you step-by-step through the design, development, and deployment of this application, empowering you to master AWS serverless technologies and EDA while solving real-world challenges.

RetoolerStock simplifies inventory management by automating essential tasks, such as:

  • Updating stock levels
  • Sending low stock alerts
  • Triggering restocking workflows

By leveraging AWS Lambda, DynamoDB, S3, and Step Functions, the application provides warehouse managers with a streamlined interface to effortlessly monitor and manage inventory. Key features include:

  • CRUD Operations: Easily add, update, and delete inventory items.
  • File Uploads: Store product-related assets in AWS S3.
  • Automated Low Stock Alerts: Receive notifications through AWS SNS to prevent stockouts.
  • Automatic Restocking: Use AWS Step Functions to make refilling inventory easier and faster.

The serverless architecture of RetoolerStock ensures automatic scaling and cost efficiency, with event-driven services like EventBridge and SQS enabling real-time updates.

But before we dive into building RetoolerStock, let’s explore two critical concepts that will underpin our application: Serverless Computing and Event-Driven Architecture (EDA).

What is Serverless Computing?

Serverless Computing

Understanding Serverless

In today’s software development landscape, especially for small teams working on internal tools, efficiency and cost management are paramount. Serverless computing has emerged as a powerful solution, enabling teams to accelerate development by eliminating the need to manage infrastructure.

In a serverless model, developers write and deploy code without having to deal with the underlying servers, which are fully managed by the cloud provider. This setup speeds up development and reduces operational overhead.

Key Characteristics of Serverless

Here are four defining characteristics that make serverless computing stand out:

  1. No Server Management: Developers can focus exclusively on writing code, as the cloud provider handles all infrastructure-related tasks, including maintenance and scaling.
  2. Automatic Scaling - Elasticity: Serverless services automatically adjust resources based on demand, scaling down to zero when idle to save costs, and scaling up seamlessly during traffic spikes.
  3. Pay-per-Use Pricing - Never Pay for Idle: With serverless, you only pay for the resources consumed during execution. If a service isn’t running, you incur no charges—unlike traditional models that require payment for allocated capacity.
  4. Built-in Availability and Security: Serverless services come with high availability and fault tolerance, ensuring continuous operation, along with robust security features managed by the provider.

These characteristics not only streamline development but also offer significant cost savings and operational efficiency, making serverless a compelling choice for modern application development.

For more insights into AWS Serverless, check out AWS Serverless.

What is Event-Driven Architecture (EDA)?

Event-Driven Architecture (EDA) is a design pattern that allows applications to respond dynamically to specific events or changes in state. Imagine it like a series of dominoes: when one domino falls (an event), it triggers a chain reaction, leading to various actions or responses.

How EDA Works

In an EDA system, we identify several key components:

  1. Events: An event signifies a significant occurrence or change in state. For instance, in our RetoolerStock application, when a warehouse manager updates an item’s stock level, that action generates an event indicating the new stock quantity.
  2. Event Producers: These are components that generate events. In RetoolerStock, the user interface or backend service that processes inventory updates serves as the event producer.
  3. Event Consumers: These components listen for events and act accordingly. For example, when the stock update event occurs, an inventory service updates the corresponding item in the database and may trigger additional actions, such as sending low stock alerts.
  4. Event Channels: These are the pathways through which events are communicated between producers and consumers. In RetoolerStock, we could use services like AWS SQS (Simple Queue Service) or EventBridge to handle the flow of events.

EDA vs Traditional Request/Response Model

EDA vs Traditional Request/Response Model

In traditional architectures, applications often operate on a synchronous request/response model. This means that when a component sends a request (like updating stock), it waits for a response before proceeding. While this approach can be straightforward, it has its limitations, especially as applications grow:

  1. Blocking Nature: In a synchronous model, if one part of the system is slow or unresponsive, it can delay the entire process. For instance, if the inventory update takes longer due to a database lock, the warehouse manager might have to wait, which can slow down operations.
  2. Tight Coupling: Components are often tightly integrated, making it harder to change or scale individual parts of the system without affecting others.

In contrast, EDA promotes asynchronous communication. Here’s how it benefits RetoolerStock:

  1. Improved Responsiveness: When an event occurs (like a stock update), the event producer doesn’t wait for the event consumer to complete its task. Instead, it can immediately continue with other processes, making the system more responsive and efficient.
  2. Decoupling of Components: EDA allows different parts of the system to evolve independently. If we decide to introduce a new consumer to handle special discount alerts when stock levels change, we can do so without disrupting the existing inventory management processes.
  3. Enhanced Scalability: Because components operate independently, we can easily scale them based on demand. For instance, if we anticipate a surge in inventory updates during a holiday sale, we can add more consumers to handle the increased event traffic without reworking the entire system.

Architecture Overview

Backend (AWS):

  • AWS Lambda: Handles CRUD operations on inventory data.
  • API Gateway (Routing Requests): Serve as the gateway for Retool to interact with Lambda functions.
  • DynamoDB: Stores inventory details like item name, stock levels, and supplier information.
  • S3: Used for storing product images, reports, and other relevant files.
  • SNS: Sends notifications to managers or suppliers when critical thresholds are met.
  • EventBridge/SQS (Event-Driven Communication): Triggers workflows or actions when key events (e.g., stock updates) occur.
  • Step Functions: Orchestrates complex workflows, like reordering items or generating and storing reports in S3.

RetoolerStock Application Architecture

Frontend (Retool):

Provides the user interface for interacting with the system (CRUD operations on inventory, file management, viewing reports).

Retool

Outro

In this first part of the series, we’ve laid out the core architecture of RetoolerStock, an inventory management application built using AWS’s powerful serverless offerings. We’ve introduced the concept of serverless computing and event-driven architecture, highlighting how these can help scale and simplify internal tools.

In the upcoming posts, we’ll dive deeper into each component of RetoolerStock, starting with how to integrate AWS Lambda and DynamoDB to handle inventory updates, followed by orchestrating workflows with Step Functions and using S3 for file storage. Step by step, you’ll learn how these services come together to create a robust application using Retool as the interface.

Stay tuned for the next post as we start building the backend logic and see how serverless technologies simplify development!

Get in Touch

Ready to bring your dashboard vision to life? Contact Retoolers today, and let us help you create a powerful, intuitive dashboard that meets your exact requirements.

Nhan Hoang
Retool Developer