mongodb.md

🍃 MongoDB Guide

DevPods provides a MongoDB 7 instance configured as a Single-Node Replica Set (rs0). This enables advanced features like multi-document ACID transactions and change streams in your local environment.

Connection Details

• URI: mongodb://localhost:27017/?replicaSet=rs0
• Web UI: http://localhost:8082 (mongo-express)
• Auth: admin / admin (basic auth for UI)

Node.js (Express + TS) Usage

Using mongoose with Express.

Installation

npm install mongoose

Reference Implementation (Transactions)

import mongoose from "mongoose";

const connectDB = async () => {
  await mongoose.connect("mongodb://localhost:27017/devdb?replicaSet=rs0");
};

// ACID Transaction Example
const processOrder = async (orderData) => {
  const session = await mongoose.startSession();
  session.startTransaction();
  try {
    const order = await Order.create([orderData], { session });
    await Inventory.updateOne(
      { item: orderData.item },
      { $inc: { stock: -1 } },
      { session },
    );
    await session.commitTransaction();
  } catch (error) {
    await session.abortTransaction();
    throw error;
  } finally {
    session.endSession();
  }
};

NestJS Usage

Using @nestjs/mongoose.

Installation

npm install @nestjs/mongoose mongoose

Configuration (app.module.ts)

import { Module } from "@nestjs/common";
import { MongooseModule } from "@nestjs/mongoose";

@Module({
  imports: [
    MongooseModule.forRoot("mongodb://localhost:27017/devdb?replicaSet=rs0"),
  ],
})
export class AppModule {}

Useful Commands

# Enter mongosh
podman exec -it dev-mongo-pod-mongodb mongosh

# Check Replica Set status
podman exec -it dev-mongo-pod-mongodb mongosh --eval "rs.status()"