chore: return original layer result

Author: carolinee21

plugins/node/opentelemetry-plugin-koa/package.json

@@ -44,11 +44,13 @@
     "@opentelemetry/context-async-hooks": "0.9.0",
     "@opentelemetry/node": "0.9.0",
     "@opentelemetry/tracing": "0.9.0",
+    "@types/koa": "^2.11.3",
     "@types/mocha": "7.0.2",
     "@types/node": "12.12.47",
     "@types/shimmer": "1.0.1",
     "codecov": "3.7.0",
     "gts": "2.0.2",
+    "koa": "^2.13.0",
     "mocha": "7.2.0",
     "nyc": "15.1.0",
     "rimraf": "3.0.2",
@@ -61,8 +63,6 @@
   "dependencies": {
     "@opentelemetry/api": "^0.9.0",
     "@opentelemetry/core": "^0.9.0",
-    "@types/koa": "^2.11.3",
-    "koa": "^2.13.0",
     "shimmer": "^1.2.1"
   }
 }

plugins/node/opentelemetry-plugin-koa/src/koa.ts

@@ -77,7 +77,7 @@ export class KoaPlugin extends BasePlugin<typeof koa> {
 
   }
 
-  private _patchLayer (oldMiddleware: KoaMiddleware) {
+  private _patchLayer (middlewareLayer: KoaMiddleware) {
     const patchedLayer = (context: KoaContext, next: koa.Next) => {
         const currentSpan = this._tracer.getCurrentSpan();
         if (!currentSpan) {
@@ -94,8 +94,9 @@ export class KoaPlugin extends BasePlugin<typeof koa> {
         mwSpan.setAttribute(AttributeNames.METHOD, context.method);
         mwSpan.setAttribute(AttributeNames.KOA_TYPE, 'middleware');
 
-        oldMiddleware(context, next);
+        var result = middlewareLayer(context, next);
         mwSpan.end();
+        return result;
 
     }
     return patchedLayer;