From 2c4a83421c979f65fd464d9599882de9a65bbc74 Mon Sep 17 00:00:00 2001
From: Matteo Gazziola <15204191+matteoga@users.noreply.github.com>
Date: Thu, 30 Dec 2021 10:24:55 +0100
Subject: [PATCH] fix(opentelemetry-instrumentation-nestjs-core): copy metadata
 to wrapped handler (#796)
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Co-authored-by: Gerhard Stöbich <deb2001-github@yahoo.de>
Co-authored-by: Daniel Dyla <dyladan@users.noreply.github.com>
---
 .../src/instrumentation.ts                    | 10 ++++
 .../test/index.test.ts                        | 34 ++++++++++++
 .../test/setup.ts                             | 54 ++++++++++++++-----
 3 files changed, 86 insertions(+), 12 deletions(-)

diff --git a/plugins/node/opentelemetry-instrumentation-nestjs-core/src/instrumentation.ts b/plugins/node/opentelemetry-instrumentation-nestjs-core/src/instrumentation.ts
index 9aa1df479ab..b753901f014 100644
--- a/plugins/node/opentelemetry-instrumentation-nestjs-core/src/instrumentation.ts
+++ b/plugins/node/opentelemetry-instrumentation-nestjs-core/src/instrumentation.ts
@@ -239,6 +239,16 @@ function createWrapHandler(
   if (handler.name) {
     Object.defineProperty(wrappedHandler, 'name', { value: handler.name });
   }
+
+  // Get the current metadata and set onto the wrapper to ensure other decorators ( ie: NestJS EventPattern / RolesGuard )
+  // won't be affected by the use of this instrumentation
+  Reflect.getMetadataKeys(handler).forEach(metadataKey => {
+    Reflect.defineMetadata(
+      metadataKey,
+      Reflect.getMetadata(metadataKey, handler),
+      wrappedHandler
+    );
+  });
   return wrappedHandler;
 }
 
diff --git a/plugins/node/opentelemetry-instrumentation-nestjs-core/test/index.test.ts b/plugins/node/opentelemetry-instrumentation-nestjs-core/test/index.test.ts
index 4dfbf2939a9..54059921288 100644
--- a/plugins/node/opentelemetry-instrumentation-nestjs-core/test/index.test.ts
+++ b/plugins/node/opentelemetry-instrumentation-nestjs-core/test/index.test.ts
@@ -110,6 +110,40 @@ describe('nestjs-core', () => {
     ]);
   });
 
+  it('should not ovewrite metadata set on the request handler', async () => {
+    const path = semver.intersects(LIB_VERSION, '<5.0.0') ? '/' : '/metadata';
+    const url = '/metadata';
+    const instance = 'MetadataController';
+    const callback = 'getMetadata';
+
+    assert.deepStrictEqual(await request('/metadata'), '["path","method"]');
+
+    assertSpans(memoryExporter.getFinishedSpans(), [
+      {
+        type: 'app_creation',
+        service: 'test',
+        name: 'Create Nest App',
+        module: 'AppModule',
+      },
+      {
+        type: 'handler',
+        service: 'test',
+        name: callback,
+        callback,
+        parentSpanName: `${instance}.${callback}`,
+      },
+      {
+        type: 'request_context',
+        service: 'test',
+        name: `${instance}.${callback}`,
+        method: 'GET',
+        url,
+        path,
+        callback,
+      },
+    ]);
+  });
+
   it('should capture errors', async () => {
     const path = semver.intersects(LIB_VERSION, '<5.0.0') ? '/' : '/errors';
     const url = '/errors';
diff --git a/plugins/node/opentelemetry-instrumentation-nestjs-core/test/setup.ts b/plugins/node/opentelemetry-instrumentation-nestjs-core/test/setup.ts
index c4ffc0e2809..1b77efe8ea1 100644
--- a/plugins/node/opentelemetry-instrumentation-nestjs-core/test/setup.ts
+++ b/plugins/node/opentelemetry-instrumentation-nestjs-core/test/setup.ts
@@ -139,6 +139,24 @@ export const setup = async (version: string): Promise<App> => {
     YellInterceptor
   );
 
+  let MetadataInterceptor = class MetadataInterceptor
+    implements NestInterceptor
+  {
+    intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
+      return next
+        .handle()
+        .pipe(map(() => Reflect.getMetadataKeys(context.getHandler())));
+    }
+  };
+  MetadataInterceptor = __decorate(
+    [
+      semver.intersects(version, '^4.0.0')
+        ? common.Interceptor()
+        : common.Injectable(),
+    ],
+    MetadataInterceptor
+  );
+
   const [UsersController, UsersModule] = makeModule(
     'Users',
     () => 'Hello, world!\n',
@@ -147,20 +165,12 @@ export const setup = async (version: string): Promise<App> => {
   const [GuardedController, GuardedModule] = makeModule(
     'Guarded',
     () => 'Hello, guarded!\n',
-    [
-      common.Controller('guarded'),
-      common.UseGuards(MyGuard),
-      common.UseGuards(MyGuard),
-    ]
+    [common.Controller('guarded'), common.UseGuards(MyGuard)]
   );
   const [InterceptedController, InterceptedModule] = makeModule(
     'Intercepted',
     () => 'Hello, Intercepted!\n',
-    [
-      common.Controller('intercepted'),
-      common.UseInterceptors(YellInterceptor),
-      common.UseInterceptors(YellInterceptor),
-    ]
+    [common.Controller('intercepted'), common.UseInterceptors(YellInterceptor)]
   );
   const [ErrorController, ErrorModule] = makeModule(
     'Error',
@@ -170,16 +180,29 @@ export const setup = async (version: string): Promise<App> => {
     [common.Controller('errors')]
   );
 
+  const [MetadataController, MetadataModule] = makeModule(
+    'Metadata',
+    () => 'Hello, Metadata!\n',
+    [common.Controller('metadata'), common.UseInterceptors(MetadataInterceptor)]
+  );
+
   if (semver.intersects(version, '>=4.6.3')) {
     AppModule = __decorate(
       [
         common.Module({
-          imports: [UsersModule, ErrorModule, GuardedModule, InterceptedModule],
+          imports: [
+            UsersModule,
+            ErrorModule,
+            GuardedModule,
+            InterceptedModule,
+            MetadataModule,
+          ],
           controllers: [
             UsersController,
             ErrorController,
             GuardedController,
             InterceptedController,
+            MetadataController,
           ],
         }),
       ],
@@ -189,12 +212,19 @@ export const setup = async (version: string): Promise<App> => {
     AppModule = __decorate(
       [
         common.Module({
-          modules: [UsersModule, ErrorModule, GuardedModule, InterceptedModule],
+          modules: [
+            UsersModule,
+            ErrorModule,
+            GuardedModule,
+            InterceptedModule,
+            MetadataModule,
+          ],
           controllers: [
             UsersController,
             ErrorController,
             GuardedController,
             InterceptedController,
+            MetadataController,
           ],
         }),
       ],