prevent neo4j handle leaks in development

backend/src/db/neo4j.ts

@@ -17,11 +17,25 @@ const defaultOptions = {
 export function getDriver(options = {}) {
   const { uri, username, password } = { ...defaultOptions, ...options }
   if (!driver) {
-    driver = neo4j.driver(uri, neo4j.auth.basic(username, password))
+    driver = neo4j.driver(uri, neo4j.auth.basic(username, password), {
+      maxConnectionPoolSize: 50,
+      connectionAcquisitionTimeout: 30000,
+    })
   }
   return driver
 }
 
+export async function closeDriver() {
+  if (driver) {
+    await driver.close()
+    driver = undefined as unknown as Driver
+  }
+  if (neodeInstance) {
+    await neodeInstance.close()
+    neodeInstance = undefined as unknown as Neode
+  }
+}
+
 let neodeInstance: Neode
 export function getNeode(options = {}) {
   if (!neodeInstance) {

backend/src/index.ts

@@ -1,10 +1,11 @@
 import CONFIG from './config'
+import { closeDriver } from './db/neo4j'
 import { loggerPlugin } from './plugins/apolloLogger'
 import createProxy from './proxy'
 import createServer from './server'
 
 async function main() {
-  const { httpServer } = await createServer({
+  const { server, httpServer } = await createServer({
     plugins: [loggerPlugin],
   })
   const url = new URL(CONFIG.GRAPHQL_URI)
@@ -31,6 +32,20 @@ async function main() {
       console.log(`Proxying requests to ${target}`)
     })
   }
+
+  // Graceful shutdown: close Neo4j driver and Apollo server on process signals.
+  // This prevents connection pool leaks during nodemon restarts in development
+  // and ensures clean shutdown in production.
+  const shutdown = async () => {
+    /* eslint-disable-next-line no-console */
+    console.log('Shutting down...')
+    await server.stop()
+    httpServer.close()
+    await closeDriver()
+    process.exit(0)
+  }
+  process.on('SIGTERM', shutdown)
+  process.on('SIGINT', shutdown)
 }
 
 // eslint-disable-next-line promise/prefer-await-to-callbacks, @typescript-eslint/use-unknown-in-catch-callback-variable