From e789bfe94f9cca3756ad0d59bddf81f997735394 Mon Sep 17 00:00:00 2001
From: Shubhendu Madhukar <shubhendumadhukar@gmail.com>
Date: Mon, 21 Nov 2022 10:30:47 +0530
Subject: [PATCH] implement basic error response and metadata. #188

---
 docs/mocking-gRPC.md                          | 26 +++++++++++++++
 .../blogPackage/BlogService/createBlog.mock   | 10 +++++-
 src/parser/GrpcParser.ts                      | 33 +++++++++++++++----
 3 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/docs/mocking-gRPC.md b/docs/mocking-gRPC.md
index b8cc299..69a6f91 100644
--- a/docs/mocking-gRPC.md
+++ b/docs/mocking-gRPC.md
@@ -107,6 +107,32 @@ You can also add delays in your grpc mock services, by adding a delay key with t
 
 You don't need to modify your proto file to accommodate the additional key, since Camouflage will delete the "delay" key from the response before sending it to the client.
 
+## Sending GRPC Error responses
+
+Camouflage provides an experimental support to send error responses starting v0.11.0 onwards, for unary and client side streaming calls. To send an error response, append a json error object with `code` and optional `message` to your mock content.
+
+```json
+{
+  "error": {
+    "code": 16,
+    "message": "User is unauthenticted."
+  }
+}
+```
+
+## Sending GRPC Error responses
+
+Camouflage provides an experimental support to send metadata/trailers with responses starting v0.11.0 onwards, for unary and client side streaming calls. To send metadata, append a json metadata object with relevant keys and values to your mock content.
+
+```json
+{
+  "metadata": {
+    "key1": "value1",
+    "key2": "value2"
+  }
+}
+```
+
 !!!caution
 
     Since the Camouflage gRPC server needs to register the new services, everytime you add a new protofile, you'd need to restart the Camouflage server. Good news is, you can do so easily by making a get request to /restart endpoint. Though the downtime is minimal (less than a second, we do not recommend restarting the server during a performance test. Note that restart is required only if you add a new protofile. If you have added a new mock file or updated an existing one, a restart is not required.
diff --git a/grpc/mocks/blogPackage/BlogService/createBlog.mock b/grpc/mocks/blogPackage/BlogService/createBlog.mock
index 301f307..2746c0c 100644
--- a/grpc/mocks/blogPackage/BlogService/createBlog.mock
+++ b/grpc/mocks/blogPackage/BlogService/createBlog.mock
@@ -1,4 +1,12 @@
 {
     "id": {{num_between lower=500 upper=600}},
-    "title": "something"
+    "title": "something",
+    "error": {
+        "code": 16,
+        "message": "User is unauthenticated."
+    },
+    "metadata": {
+        "key1": "value1",
+        "key2": "value2"
+    }
 }
diff --git a/src/parser/GrpcParser.ts b/src/parser/GrpcParser.ts
index b18932e..d903c5a 100644
--- a/src/parser/GrpcParser.ts
+++ b/src/parser/GrpcParser.ts
@@ -6,6 +6,7 @@ import { getHandlebars } from '../handlebar'
 import { getLoaderInstance } from "../ConfigLoader";
 import { CamouflageConfig } from "../ConfigLoader/LoaderInterface";
 const Handlebars = getHandlebars()
+import * as grpc from "@grpc/grpc-js";
 /**
  * Parser class for GRPC Protocol mocks to define handlers for:
  * - Unary calls
@@ -42,16 +43,26 @@ export default class GrpcParser {
         const response = JSON.parse(fileContent);
         const delay: number = response.delay || 0;
         delete response.delay;
+        const error = response.error || null
+        delete response.error;
+        const metadata = response.metadata || null;
+        delete response.metadata;
+        const trailers = new grpc.Metadata();
+        if (metadata) {
+          for (const key in metadata) {
+            trailers.add(key, metadata[key])
+          }
+        }
         setTimeout(() => {
-          callback(null, response);
+          callback(error, response, trailers);
         }, delay);
       } else {
         logger.error(`No suitable mock file was found for ${mockFilePath}`);
-        callback(null, { error: `No suitable mock file was found for ${mockFilePath}` });
+        callback({ code: 5, message: `No suitable mock file was found for ${mockFilePath}` }, {});
       }
     } catch (error) {
       logger.error(error);
-      callback(null, { error: error });
+      callback({ code: 10, message: error }, {});
     }
   };
   /**
@@ -137,16 +148,26 @@ export default class GrpcParser {
           const response = JSON.parse(fileContent);
           const delay: number = response.delay || 0;
           delete response.delay;
+          const error = response.error || null;
+          delete response.error
+          const metadata = response.metadata || null;
+          delete response.metadata;
+          const trailers = new grpc.Metadata();
+          if (metadata) {
+            for (const key in metadata) {
+              trailers.add(key, metadata[key])
+            }
+          }
           setTimeout(() => {
-            callback(null, response);
+            callback(error, response, trailers);
           }, delay);
         } else {
           logger.error(`No suitable mock file was found for ${mockFilePath}`);
-          callback(null, { error: `No suitable mock file was found for ${mockFilePath}` });
+          callback({ code: 5, error: `No suitable mock file was found for ${mockFilePath}` }, {});
         }
       } catch (error) {
         logger.error(error);
-        callback(null, { error: error });
+        callback({ code: 10, message: error }, {});
       }
     });
   };