fix(api): Explicitly generate metadata for nest build script (#6329)

apps/api/.gitignore

@@ -118,3 +118,6 @@ fabric.properties
 newrelic_agent.log
 
 backups/
+
+# Nest.js auto-generated metadata (https://docs.nestjs.com/recipes/swc#monorepo-and-cli-plugins)
+src/metadata.ts

apps/api/package.json

@@ -7,7 +7,7 @@
   "license": "MIT",
   "scripts": {
     "prebuild": "rimraf dist",
-    "build": "nest build",
+    "build": "pnpm build:metadata && nest build",
     "format": "prettier --write \"src/**/*.ts\"",
     "docker:build": "pnpm --silent --workspace-root pnpm-context -- apps/api/Dockerfile | BULL_MQ_PRO_NPM_TOKEN=${BULL_MQ_PRO_NPM_TOKEN} docker buildx build --load -t novu-api --secret id=BULL_MQ_PRO_NPM_TOKEN --build-arg PACKAGE_PATH=apps/api - $DOCKER_BUILD_ARGUMENTS",
     "docker:build:depot": "pnpm --silent --workspace-root pnpm-context -- apps/api/Dockerfile | depot build --build-arg PACKAGE_PATH=apps/api - -t novu-api --load",
@@ -16,6 +16,7 @@
     "start:test": "cross-env NODE_ENV=test PORT=1336 nest start --watch",
     "start:debug": "nest start --debug",
     "start:prod": "node dist/main.js",
+    "build:metadata": "cross-env ts-node scripts/generate-metadata.ts",
     "lint": "eslint src",
     "lint:fix": "pnpm lint -- --fix",
     "lint:openapi": "spectral lint http://127.0.0.1:${PORT:-3000}/openapi.yaml",

apps/api/scripts/generate-metadata.ts

@@ -0,0 +1,32 @@
+/**
+ * This file is responsible for generating Nest.js metadata for the API.
+ * Metadata generation is required when using SWC with Nest.js due to SWC
+ * not natively supporting Typescript, which is required to use the `reflect-metadata`
+ * API and in turn, resolve types for the OpenAPI specification.
+ *
+ * @see https://docs.nestjs.com/recipes/swc#monorepo-and-cli-plugins
+ */
+import fs from 'node:fs';
+import path from 'node:path';
+import { PluginMetadataGenerator } from '@nestjs/cli/lib/compiler/plugins';
+import { ReadonlyVisitor } from '@nestjs/swagger/dist/plugin';
+
+const tsconfigPath = 'tsconfig.build.json';
+const srcPath = path.join(__dirname, '..', 'src');
+const metadataPath = path.join(srcPath, 'metadata.ts');
+
+/*
+ * We create an empty metadata file to ensure that files importing `metadata.ts`
+ * will compile successfully before the metadata generation occurs.
+ */
+const defaultContent = `export default async () => { return {}; };`;
+
+fs.writeFileSync(metadataPath, defaultContent, 'utf8');
+console.log('metadata.ts file has been generated with default content.');
+
+const generator = new PluginMetadataGenerator();
+generator.generate({
+  visitors: [new ReadonlyVisitor({ introspectComments: true, pathToSource: srcPath })],
+  outputDir: srcPath,
+  tsconfigPath,
+});

apps/api/src/app/shared/framework/swagger/swagger.controller.ts

@@ -5,6 +5,8 @@ import { injectDocumentComponents } from './injection';
 import { API_KEY_SWAGGER_SECURITY_NAME } from '@novu/application-generic';
 import { SecuritySchemeObject } from '@nestjs/swagger/dist/interfaces/open-api-spec.interface';
 import { removeEndpointsWithoutApiKey, transformDocument } from './open.api.manipulation.component';
+// Necessary to resolve ESlint errors that surface before metadata generation
+// eslint-disable-next-line import/extensions
 import metadata from '../../../../metadata';
 
 export const API_KEY_SECURITY_DEFINITIONS: SecuritySchemeObject = {