fix: Handle error for already streaming response gracefully (kyma-project#3805)

Author: chriskari

backend/companion/companionRouter.js

@@ -158,7 +158,18 @@ async function handleChatMessage(req, res) {
 
     res.end();
   } catch (error) {
-    res.status(500).json({ error: 'Failed to fetch AI chat data' });
+    if (!res.headersSent) {
+      res.status(500).json({ error: 'Failed to fetch AI chat data' });
+    } else {
+      setTimeout(() => {
+        res.write(
+          JSON.stringify({
+            error: 'Failed to fetch AI chat data',
+          }),
+        );
+        res.end();
+      }, 500);
+    }
   }
 }
 

backend/companion/getKcpToken.js

@@ -75,7 +75,7 @@ function getSecretManagerCredentials() {
         .trim(),
     };
   } catch (error) {
-    console.warn('Secret Manager credentials could not be read:', error);
+    console.warn('Secret Manager credentials could not be read');
     return null;
   }
 }

src/components/KymaCompanion/api/getChatResponse.ts

@@ -98,9 +98,9 @@ function readChunk(
       }
       const receivedString = decoder.decode(value, { stream: true });
       const chunk = JSON.parse(receivedString);
-      if (chunk?.data?.error) {
-        handleError(chunk.data.error);
-        return;
+      // custom error provided by busola backend during streaming, not by companion backend
+      if (chunk?.error) {
+        throw new Error(chunk?.error);
       }
       handleChatResponse(chunk);
       readChunk(reader, decoder, handleChatResponse, handleError, sessionID);