brackt/server/app.ts
Chris Parsons 180aad1520
Fix postgres connection pool leak in development (#195)
In dev mode, viteDevServer.ssrLoadModule re-evaluates server/app.ts on
every request, creating a new postgres connection pool each time and
eventually exhausting Postgres's max_connections limit. Cache the client
on globalThis so HMR re-evaluations reuse the same pool.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-21 09:57:53 -07:00

37 lines
1.6 KiB
TypeScript

import { createRequestHandler } from "@react-router/express";
import { drizzle } from "drizzle-orm/postgres-js";
import express from "express";
import postgres from "postgres";
import type { ServerBuild } from "react-router";
import { RouterContextProvider } from "react-router";
import { DatabaseContext } from "~/database/context";
import * as schema from "~/database/schema";
import { expressValueContext } from "~/contexts/express";
export const app = express();
if (!process.env.DATABASE_URL) throw new Error("DATABASE_URL is required");
// In dev, ssrLoadModule re-evaluates this file on every request. Cache the
// client on globalThis so HMR re-loads reuse the same connection pool instead
// of leaking a new one each time.
declare global {
// TypeScript requires `var` in `declare global` blocks — `let`/`const` are not allowed here.
var __pgClient: ReturnType<typeof postgres> | undefined; // eslint-disable-line no-var
}
const client = (globalThis.__pgClient ??= postgres(process.env.DATABASE_URL));
const db = drizzle(client, { schema });
app.use((_, __, next) => DatabaseContext.run(db, next));
app.use(
createRequestHandler({
build: () => import("virtual:react-router/server-build") as unknown as Promise<ServerBuild>,
// @ts-ignore -- RouterContextProvider is the correct runtime type but tsconfig.server.json can't resolve the conditional type statically
getLoadContext() {
const provider = new RouterContextProvider();
provider.set(expressValueContext, "Hello from Express");
return provider as unknown as RouterContextProvider;
},
}),
);