Migrate to MongoDB

api/app.js

@@ -1,8 +1,8 @@
 import express from "express";
 
 import apiRouter from "./api.js";
-import db from "./db.js";
-import config from "./utils/config.cjs";
+import { testConnection } from "./db.js";
+import config from "./utils/config.js";
 import {
 	asyncHandler,
 	clientRouter,
@@ -27,7 +27,7 @@ if (config.production) {
 app.get(
 	"/healthz",
 	asyncHandler(async (_, res) => {
-		await db.query("SELECT 1;");
+		await testConnection();
 		res.sendStatus(200);
 	}),
 );

api/db.js

@@ -1,30 +1,27 @@
-import pg from "pg";
+import mongoose from "mongoose";
 
 import logger from "./utils/logger.js";
 
-/** @type {pg.Pool} */
-let pool;
-
 /**
- * @param {import("pg").ClientConfig} config
+ * @param {string} uri
+ * @param {import("mongoose").ConnectOptions} [options]
  */
-export const connectDb = async (config) => {
-	pool = new pg.Pool(config);
-	pool.on("error", (err) => logger.error("%O", err));
-	const client = await pool.connect();
-	logger.info("connected to %s", client.database);
-	client.release();
+export const connectDb = async (uri, options) => {
+	mongoose.connection.on("error", (err) => logger.error("%O", err));
+	const client = await mongoose.connect(uri, {
+		bufferCommands: false,
+		...options,
+	});
+	logger.info("connected to %s", client.connection.name);
 };
 
 export const disconnectDb = async () => {
-	if (pool) {
-		await pool.end();
-	}
+	await mongoose.disconnect();
 };
 
-export default {
-	query(...args) {
-		logger.debug("Postgres query: %O", args);
-		return pool.query.apply(pool, args);
-	},
+export const testConnection = async () => {
+	const state = mongoose.connection.readyState;
+	if (state !== mongoose.ConnectionStates.connected) {
+		throw new Error(`database connection state: ${mongoose.STATES[state]}`);
+	}
 };

api/messages/messageRepository.js

@@ -1,6 +1,10 @@
-import db from "../db.js";
+import mongoose from "mongoose";
+
+const MessageSchema = new mongoose.Schema({ content: String });
+
+const Message = mongoose.model("messages", MessageSchema);
 
 export async function getAll() {
-	const { rows } = await db.query("SELECT * FROM message;");
+	const rows = await Message.find();
 	return rows;
 }

api/migrate-mongo-config.js

@@ -0,0 +1,16 @@
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import config from "./utils/config.js";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+/** @type {import("migrate-mongo").config.Config} */
+export default {
+	changelogCollectionName: "changelog",
+	migrationFileExtension: ".js",
+	migrationsDir: join(__dirname, "migrations"),
+	moduleSystem: "esm",
+	mongodb: { url: config.dbUrl },
+	useFileHash: false,
+};

api/migrations/20240916162136-welcome-message.js

@@ -0,0 +1,21 @@
+/**
+ * Template for
+ * {@link https://github.com/seppevs/migrate-mongo?tab=readme-ov-file#creating-a-new-migration-script defining migrations}.
+ */
+
+/**
+ * @param {import("mongodb").Db} db
+ * @param {import("mongodb").MongoClient} client
+ */
+export const up = async (db) => {
+	await db.collection("messages").insertOne({ content: "Hello, world!" });
+};
+
+/**
+ *
+ * @param {import("mongodb").Db} db
+ * @param {import("mongodb").MongoClient} client
+ */
+export const down = async (db) => {
+	await db.collection("messages").drop();
+};

api/migrations/sample-migration.js

@@ -0,0 +1,20 @@
+/**
+ * Template for
+ * {@link https://github.com/seppevs/migrate-mongo?tab=readme-ov-file#creating-a-new-migration-script defining migrations}.
+ */
+
+/**
+ * @param {import("mongodb").Db} db
+ * @param {import("mongodb").MongoClient} client
+ */
+export const up = async (db, client) => {
+	// TODO write your migration here.
+};
+
+/**
+ * @param {import("mongodb").Db} db
+ * @param {import("mongodb").MongoClient} client
+ */
+export const down = async (db, client) => {
+	// TODO reverse your migration here.
+};

api/package.json

@@ -7,21 +7,21 @@
 	"type": "module",
 	"scripts": {
 		"dev": "cross-env LOG_LEVEL=debug node --inspect --watch --watch-path . server.js",
-		"migration": "node-pg-migrate --config-file ./migrations/config.cjs",
-		"test": "cross-env DATABASE_URL=http://example.com NODE_OPTIONS='--experimental-vm-modules' jest",
+		"migration": "migrate-mongo",
+		"test": "cross-env MONGO_URL=http://example.com NODE_OPTIONS='--experimental-vm-modules' jest",
 		"test:watch": "npm run test -- --watch"
 	},
 	"dependencies": {
 		"dotenv": "^16.4.5",
 		"express": "^4.21.0",
 		"helmet": "^7.1.0",
+		"migrate-mongo": "^11.0.0",
+		"mongoose": "^8.6.2",
 		"morgan": "^1.10.0",
-		"node-pg-migrate": "^7.6.1",
-		"pg": "^8.12.0",
 		"winston": "^3.14.2"
 	},
 	"devDependencies": {
-		"@testcontainers/postgresql": "^10.13.1",
+		"@testcontainers/mongodb": "^10.13.1",
 		"eslint-plugin-jest": "^28.8.3",
 		"eslint-plugin-n": "^17.10.2",
 		"jest": "^29.7.0",

api/server.js

@@ -1,10 +1,10 @@
 import app from "./app.js";
 import { connectDb } from "./db.js";
-import config from "./utils/config.cjs";
+import config from "./utils/config.js";
 import logger from "./utils/logger.js";
 
 const { port } = config;
 
-await connectDb(config.dbConfig);
+await connectDb(config.dbUrl);
 
 app.listen(port, () => logger.info(`listening on ${port}`));

api/setupTests.js

@@ -1,21 +1,22 @@
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 
-import { PostgreSqlContainer } from "@testcontainers/postgresql";
-import { runner } from "node-pg-migrate";
+import { MongoDBContainer } from "@testcontainers/mongodb";
+import { config, database, up } from "migrate-mongo";
 
 import { connectDb, disconnectDb } from "./db.js";
+import logger from "./utils/logger.js";
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
-/** @type {import("@testcontainers/postgresql").StartedPostgreSqlContainer} */
+/** @type {import("@testcontainers/mongodb").StartedMongoDBContainer} */
 let dbContainer;
 
 beforeAll(async () => {
-	dbContainer = await new PostgreSqlContainer().start();
-	const connectionString = dbContainer.getConnectionUri();
+	dbContainer = await new MongoDBContainer().start();
+	const connectionString = dbContainer.getConnectionString();
 	await applyMigrations(connectionString);
-	await connectDb({ connectionString });
+	await connectDb(connectionString, { directConnection: true });
 }, 60_000);
 
 afterAll(async () => {
@@ -25,11 +26,17 @@ afterAll(async () => {
 	}
 });
 
-async function applyMigrations(databaseUrl) {
-	await runner({
-		databaseUrl,
-		dir: join(__dirname, "migrations"),
-		direction: "up",
-		ignorePattern: "(config|template)\\.cjs$",
+async function applyMigrations(url) {
+	config.set({
+		changelogCollectionName: "changelog",
+		migrationFileExtension: ".js",
+		migrationsDir: join(__dirname, "migrations"),
+		mongodb: { url, options: { directConnection: true } },
+		useFileHash: false,
 	});
+	const { db, client } = await database.connect();
+	const migrations = await up(db, client);
+	for (const migration of migrations) {
+		logger.info("Run migration: %s", migration);
+	}
 }

api/utils/README.md

@@ -6,16 +6,14 @@
 - Import from `logger.js`; and
 - Ignore `middleware.js` entirely (all predefined middleware is already used in `app.js`).
 
-## `config.cjs`
+## `config.js`
 
 Creates and exposes an object representing the app's configuration. This centralises access to the environment and definition of default values.
 
 [Dotenv] is used to load any configuration required from a `.env` file in the root of the repository.
 
 To check if this is being used correctly, if you search your codebase, _all_ uses of `process.env` in `api/` should be in this file.
 
-**Note** this is CommonJS (`.cjs`) rather than an ES module so that it can be used by `node-pg-migrate` and similar tools, to avoid duplicating configuration.
-
 ## `logger.js`
 
 Creates, configures and exports a [Winston] logger, which you can then import and use elsewhere:

api/utils/config.cjs → api/utils/config.js

@@ -1,41 +1,27 @@
-/* eslint-disable no-restricted-syntax */
-const { join, resolve } = require("node:path");
+import { dirname, join, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
 
-const { configDotenv } = require("dotenv");
+import { configDotenv } from "dotenv";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
 
 const dotenvPath = resolve(
 	join(__dirname, "..", "..", process.env.DOTENV_CONFIG_PATH ?? ".env"),
 );
 
 configDotenv({ path: dotenvPath });
 
-requireArgs(["DATABASE_URL"]);
-
-const databaseUrl = new URL(process.env.DATABASE_URL);
-
-const localDb = [
-	"0.0.0.0",
-	"127.0.0.1",
-	"localhost",
-	"host.docker.internal",
-].includes(databaseUrl.hostname);
-const sslMode = ["prefer", "require", "verify-ca", "verify-full"].includes(
-	databaseUrl.searchParams.get("sslmode") ?? process.env.PGSSLMODE,
-);
+requireArgs(["MONGO_URL"]);
 
 /**
- * @property {import("pg").ClientConfig} dbConfig
+ * @property {string} dbUrl
  * @property {string} dotenvPath
  * @property {string} logLevel
  * @property {number} port
  * @property {boolean} production
  */
-module.exports = {
-	dbConfig: {
-		connectionString: databaseUrl.toString(),
-		connectionTimeoutMillis: 5_000,
-		ssl: localDb ? false : { rejectUnauthorized: sslMode },
-	},
+export default {
+	dbUrl: process.env.MONGO_URL,
 	dotenvPath,
 	logLevel: process.env.LOG_LEVEL?.toLowerCase() ?? "info",
 	port: parseInt(process.env.PORT ?? "3000", 10),

api/utils/logger.js

@@ -1,6 +1,6 @@
 import { createLogger, format, transports } from "winston";
 
-import config from "./config.cjs";
+import config from "./config.js";
 
 const logger = createLogger({
 	format: format.combine(

eslint.config.js

@@ -44,15 +44,16 @@ export default [
 				},
 			],
 		},
+		ignores: ["api/utils/config.js"],
 	},
 	{
 		files: ["**/*.cjs"],
 		...nodePlugin.configs["flat/recommended-script"],
 	},
 	{
-		files: ["api/migrations/template.cjs"],
+		files: ["api/migrations/sample-migration.js"],
 		rules: {
-			"no-unused-vars": ["error", { argsIgnorePattern: "pgm" }],
+			"no-unused-vars": ["error", { argsIgnorePattern: "client|db" }],
 		},
 	},
 	{