fix: drain request after shutdown

Signed-off-by: Camila Belo <camilaibs@gmail.com>

packages/backend-app-api/src/wiring/BackendInitializer.ts

@@ -65,9 +65,18 @@ const instanceRegistry = new (class InstanceRegistry {
     if (!this.#registered) {
       this.#registered = true;
 
-      process.addListener('SIGTERM', this.#exitHandler);
-      process.addListener('SIGINT', this.#exitHandler);
-      process.addListener('beforeExit', this.#exitHandler);
+      process.addListener('SIGTERM', () => {
+        this.#exitHandler();
+      });
+      process.addListener('SIGINT', () => {
+        this.#exitHandler();
+      });
+      process.addListener('SIGQUIT', () => {
+        process.exit(0);
+      });
+      process.addListener('beforeExit', () => {
+        this.#exitHandler();
+      });
     }
 
     this.#instances.add(instance);
@@ -79,12 +88,18 @@ const instanceRegistry = new (class InstanceRegistry {
 
   #exitHandler = async () => {
     try {
-      const results = await Promise.allSettled(
-        Array.from(this.#instances).map(b => b.stop()),
-      );
-      const errors = results.flatMap(r =>
-        r.status === 'rejected' ? [r.reason] : [],
-      );
+      // This signals to the healthcheck service that the process is shutting down
+      process.exitCode = 0;
+
+      const results = await Promise.race([
+        // Give the backend 30 seconds to shut down, then force exit
+        new Promise(resolve => setTimeout(resolve, 30000)),
+        Promise.allSettled(Array.from(this.#instances).map(b => b.stop())),
+      ]);
+
+      const errors = Array.isArray(results)
+        ? results.flatMap(r => (r.status === 'rejected' ? [r.reason] : []))
+        : [];
 
       if (errors.length > 0) {
         for (const error of errors) {

packages/backend-defaults/src/entrypoints/rootHealth/rootHealthServiceFactory.test.ts

@@ -51,6 +51,24 @@ describe('DefaultRootHealthService', () => {
       });
     });
 
+    it(`should return a 503 response if the server is stopping`, async () => {
+      const service = new DefaultRootHealthService({
+        lifecycle: mockServices.rootLifecycle.mock(),
+      });
+
+      process.exitCode = 1;
+
+      await expect(service.getReadiness()).resolves.toEqual({
+        status: 503,
+        payload: {
+          message: 'Backend has not started yet',
+          status: 'error',
+        },
+      });
+
+      process.exitCode = undefined; // Reset exitCode for other tests
+    });
+
     it(`should return a 500 response if the server has stopped`, async () => {
       let mockServerStartedFn = () => {};
       let mockServerStoppedFn = () => {};

packages/backend-defaults/src/entrypoints/rootHealth/rootHealthServiceFactory.ts

@@ -39,7 +39,8 @@ export class DefaultRootHealthService implements RootHealthService {
   }
 
   async getReadiness(): Promise<{ status: number; payload?: any }> {
-    if (!this.#isRunning) {
+    // If the process has been told to exit, or if the backend has not started yet
+    if (process.exitCode !== undefined || !this.#isRunning) {
       return {
         status: 503,
         payload: { message: 'Backend has not started yet', status: 'error' },