🧃 Vending Machine POC — Go + GraphQL

A proof-of-concept (POC) microservice that models a vending machine backend using Golang, GraphQL, and PostgreSQL. This application is cloud-ready and includes modules to simulate multi-cloud scenarios (AWS, OCI).

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🚀 Overview

This project allows users to query and mutate vending machine inventory and simulate user interactions via a GraphQL API. It's useful as a base for learning GraphQL server-side development in Go, infrastructure integration (OCI/AWS), and database schema management.

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🧱 Tech Stack

• GoLang – Backend language
• GraphQL – API query language (via gqlgen)
• PostgreSQL – Relational database
• Docker – Containerized deployment
• Fly.io – (Optional) For deployment
• AWS / OCI modules – For cloud resource emulation

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📁 Folder Structure

vending-machine-golang-graphql/
├── awscompose/              # AWS simulation logic
├── base/                    # DB helper and init logic
├── ocicompose/              # OCI simulation logic
├── graph/
│   ├── schema.graphqls      # GraphQL schema
│   ├── resolver.go          # Root resolver
│   └── model/               # Auto-generated models
├── documentation/           # Setup guides & images
├── Dockerfile               # Docker build script
├── server.go                # Main Go entrypoint
└── docker-compose.yml       # Orchestration

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🛠 Setup Guide

📦 Dependencies

• Go 1.18+
• PostgreSQL
• gqlgen (go install github.com/99designs/gqlgen@latest)

🧪 Local Dev Setup

git clone https://github.com/your-org/vending-machine-golang-graphql.git
cd vending-machine-golang-graphql
go run ./server.go

Open your browser at: http://localhost:8080
GraphQL Playground will be available.

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⚙️ Presetup (Cloud + DB)

• 📘 Cloud Setup
• 🗃️ DB Setup

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💻 Sample Queries

Query Example

query {
  items {
    id
    name
    price
  }
}

Mutation Example

mutation {
  addItem(input: {
    name: "Coca-Cola",
    price: 1.5
  }) {
    id
    name
  }
}

More examples in:

• sample-scripts-query.gql
• sample-scripts-mutations.gql

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✍️ Author

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