fix: record error response attributes

Author: tschoffelen

README.md

@@ -1,6 +1,14 @@
 # Serverless Middleware
 
-Some helpers for writing API endpoints using AWS Lambda.
+A helper for writing APIs using AWS Lambda functions.
+
+### Features
+
+- Dependency injection for easy unit testing.
+- Pretty JSON error output, with status codes automatically determined based on error message.
+- Easy access to query strings and JSON body properties.
+- Serverless warmup plugin support.
+- OpenTelemetry support and additional span attributes, for use with [opentelemetry-lambda](https://github.com/open-telemetry/opentelemetry-lambda).
 
 ---
 
@@ -47,6 +55,10 @@ serverless plugin.
 Simply install the serverless plugin, no other changes to your code necessary.
 The middleware will automatically prevent code execution on warmup requests.
 
+### OpenTelemetry span enrichment
+
+If an active OpenTelemetry span is detected, event and response properties will automatically be added.
+
 <br /><br />
 
 ---

src/lib/ApiAdapter.js

@@ -69,8 +69,13 @@ class ApiAdapter {
       return res;
     } catch (error) {
       console.error(error);
+
       OpenTelemetry.addSpanErrorAttributes(event, error);
-      return this.errorConverter.convert(error);
+
+      const res = this.errorConverter.convert(error);
+      OpenTelemetry.addSpanResponseAttributes(event, res);
+
+      return res;
     }
   }