server.ts

import express from "express";
import mongoose from "mongoose";
import { BulkHead } from "./BulkHead";

const app = express();

// A very strict bulkhead for demonstration: 2 concurrent tasks, 5 in queue
const dbBulkhead = new BulkHead(2, 5);

// A simple Schema
const User = mongoose.model('User', new mongoose.Schema({ name: String }));

app.get('/slow-db', async (req, res) => {
    try {

        const data = await dbBulkhead.run(async () => {
            // Simulate a slow DB operation
            await new Promise(resolve => setTimeout(resolve, 2000));
            return User.find().exec();
        });

        res.json(data);
    } catch (error) {
        // If the bulkhead queue is full, this will catch the "Server Busy" error
        res.status(503).json({ error: (error as Error).message });
    }
})


// THE HEALTHY ROUTE(Should stay responsive)
app.get('/ping', (req, res) => res.send('pong!'));


mongoose.connect('mongodb://localhost:27017/bulkhead').then(() => {
    console.log('Connected to MongoDB');
    app.listen(3000, () => {
        console.log('Server is running on port 3000');
    });
}).catch(err => {
    console.error('Failed to connect to MongoDB', err);
});