🗺️ EPIC Internship Complete Learning Guide — Master Index

For: Amazon EPIC (Everyday Peak In Charge) internship
Purpose: Understand every file, every folder, every system in the EPIC project — from zero knowledge to internship-ready
Covers: JavaScript, React, TypeScript, Java, AWS CDK, DynamoDB, MySQL, SQS, SNS, Lambda, API Gateway, and all Amazon internal systems

📁 The EPIC Project Has 4 Main Parts

EPIC/
├── EPICFrontend/          ← React web app (what users see and click)
├── EPICBackend/           ← Node.js Lambda functions (REST APIs + DB logic)
├── EPICBackendCDK/        ← AWS CDK TypeScript (cloud infrastructure setup)
└── EPICBackendTriggers/   ← Java Lambda functions (automated background jobs)

Think of it like a restaurant:

• EPICFrontend = The dining room (customers interact here)
• EPICBackend = The kitchen (processes orders, stores data)
• EPICBackendCDK = The building blueprints (sets up all the equipment)
• EPICBackendTriggers = The automated machines (run on schedule, do heavy lifting)

📚 Reading Order (Follow This Exactly)

🟢 Phase 1 — Previously Created (HotwHelper Focus)

In the HOTW Java Guide (2_HOTW_Java_Guide/):

🔵 Phase 2 — This Guide (Entire EPIC Project)

These files are in this guide (1_EPIC_Learning_Guide/):

🏗️ Complete Project Architecture

┌─────────────────────────────────────────────────────────────────────┐
│                     USER (Service Owner / Leader)                    │
│                     Uses EPIC Frontend (React App)                   │
└─────────────────────────┬───────────────────────────────────────────┘
                          │ HTTPS calls
                          ▼
┌─────────────────────────────────────────────────────────────────────┐
│                     API Gateway (REST API)                           │
│              /service, /fleet, /event, /hotw, /projection            │
└────────┬──────────────────────────────────┬─────────────────────────┘
         │ triggers                          │ triggers
         ▼                                  ▼
┌─────────────────────┐          ┌─────────────────────────┐
│  EPICBackend        │          │  EPICBackendTriggers     │
│  (Node.js Lambda)   │          │  (Java Lambda)           │
│                     │          │                          │
│  • Fleet CRUD       │          │  • HotwHandler           │
│  • Service CRUD     │          │  • ApolloHandler         │
│  • Event CRUD       │          │  • MilestoneHandlers     │
│  • HOTW APIs        │          │  • BAU Handlers          │
│  • Projection APIs  │          │  • FMC Handler           │
│  • Throttling APIs  │          │  • FLO Handler           │
│  • Ticket APIs      │          │  • Throttling Executor   │
└─────────┬───────────┘          └──────────┬──────────────┘
          │                                  │
          ▼                                  ▼
┌─────────────────────────────────────────────────────────────────────┐
│                     AWS Infrastructure                               │
│  DynamoDB (NoSQL)  │  MySQL/Aurora (SQL)  │  SQS Queues  │  SNS     │
│  ─────────────     │  ───────────────     │  ─────────── │  ───     │
│  FleetTable        │  hotwdashboard       │  AtomicHOTW  │ Milestone│
│  ServiceTable      │  hotwexecution       │  FMC queue   │ SNS      │
│  EventTable        │  asgdetails          │  Apollo queue│          │
│  EventPlanTable    │  capacityoverride    │  BAU queue   │          │
│  ProjectionsTable  │  fulfillmentdetails  │  30+ queues  │          │
└─────────────────────────────────────────────────────────────────────┘
          │
          ▼
┌─────────────────────────────────────────────────────────────────────┐
│                     Amazon Internal Systems                          │
│  Apollo (config) │ FMC (hardware orders) │ SIM (tickets) │ Axon     │
│  EAP (ASG enroll)│ SPCO (capacity req)   │ PMET (metrics)│ Gizmo    │
│  CloudTune (ML)  │ ScalingPlanner        │ TES (events)  │ FLO      │
└─────────────────────────────────────────────────────────────────────┘

📊 File Count Summary

🎯 What EPIC Actually Does (30 Seconds Summary)

1. Before a Peak Event (Prime Day, Black Friday, etc.):

   • Teams enter their traffic projections (how many requests per minute they expect)
   • EPIC calculates how many servers each team needs
   • EPIC automatically places hardware orders via FMC/SPCO
   • EPIC opens SIM tickets to track progress
   • EPIC checks that all “milestones” are complete before the event

2. During the Peak:

   • EPIC monitors if enough servers are available
   • EPIC handles “emergent” orders if servers are running short
   • EPIC manages throttling configurations in Gizmo/SDC

3. After the Peak:

   • EPIC recommends descaling (returning extra servers)
   • EPIC automates the descale orders
   • EPIC tracks fulfillment of descale orders

🔑 Key Terms You Must Know Before Reading Anything

💡 How the 4 Modules Talk to Each Other

EPICFrontend
    │
    │  HTTP calls (via API Gateway)
    ▼
EPICBackend (Node.js)
    │         │
    │         │  Stores/reads data
    ▼         ▼
DynamoDB    MySQL/Aurora
    │
    │  DynamoDB Streams trigger Java Lambda
    ▼
EPICBackendTriggers (Java)
    │
    │  SQS messages trigger more Java Lambdas
    ▼
Amazon Internal Systems (Apollo, FMC, SPCO, SIM...)

Key insight: When a user clicks a button in the frontend:

1. Frontend calls Backend REST API
2. Backend stores data in DynamoDB
3. DynamoDB change triggers a Java Lambda
4. Java Lambda calls external systems (Apollo, FMC, SIM)
5. Java Lambda publishes result to SNS
6. SNS triggers more Lambda functions
7. Eventually dashboard is updated
8. Frontend polls and shows updated data

🚀 Start Here Based on Your Task