Add status serialization to metadata and send with grpc status

Author: zarinn3pal

examples/error_details/client.js

@@ -31,6 +31,11 @@ var packageDefinition = protoLoader.loadSync(
   });
 var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
 
+// Extract Deserializers from the service definition
+var serviceDef = hello_proto.Greeter.service;
+var decodeStatus = serviceDef['_DecodeStatus'].responseDeserialize;
+var decodeBadRequest = serviceDef['_DecodeBadRequest'].responseDeserialize;
+
 var client = new hello_proto.Greeter('localhost:50051', grpc.credentials.createInsecure());
 
 function main() {
@@ -47,6 +52,23 @@ function main() {
         console.log(`Code: ${err.code}`);
         console.log(`Status: ${grpc.status[err.code]}`);
         console.log(`Message: ${err.message}`);
+
+        // Rich Error Decoding
+        const [statusBuffer] = err.metadata?.get('grpc-status-details-bin') || [];
+        if (statusBuffer) {
+          console.log('\n--- Rich Error Details (Native) ---');
+          var statusObj = decodeStatus(statusBuffer);
+
+          if (statusObj.details) {
+            statusObj.details.forEach(detail => {
+              if (detail.type_url === 'type.googleapis.com/google.rpc.BadRequest') {
+                var badRequestObj = decodeBadRequest(detail.value);
+                console.log('Violation:', JSON.stringify(badRequestObj.field_violations, null, 2));
+              }
+            });
+          }
+        }
+        
       } else {
         console.log('Failing call unexpectedly succeeded:', response.message);
       }

examples/error_details/server.js

@@ -31,14 +31,43 @@ var packageDefinition = protoLoader.loadSync(
   });
 var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
 
+// Extract Serializers
+var serviceDef = hello_proto.Greeter.service;
+var encodeStatus = serviceDef['_EncodeStatus'].requestSerialize;
+var encodeBadRequest = serviceDef['_EncodeBadRequest'].requestSerialize;
+
 /**
  * Implements the SayHello RPC method.
  */
 function sayHello(call, callback) {
   if (call.request.name === '') {
+    //Serialize the BadRequest detail
+    var badRequestBuffer = encodeBadRequest({
+      field_violations: [
+        { field: 'name', description: 'Name field is required' }
+      ]
+    });
+
+    //Create and Serialize the Status Message
+    var statusBuffer = encodeStatus({
+      code: 3,
+      message: 'Request argument invalid',
+      details: [
+        {
+          type_url: 'type.googleapis.com/google.rpc.BadRequest',
+          value: badRequestBuffer
+        }
+      ]
+    });
+
+    // Attach Metadata
+    var metadata = new grpc.Metadata();
+    metadata.add('grpc-status-details-bin', statusBuffer);
+
     callback({
       code: grpc.status.INVALID_ARGUMENT,
-      details: 'Simple Error: The name field was empty.'
+      details: 'Simple Error: The name field was empty.',
+      metadata: metadata
     });
     return;
   }

examples/protos/helloworld.proto

@@ -27,6 +27,12 @@ service Greeter {
   rpc SayHello (HelloRequest) returns (HelloReply) {}
 
   rpc SayHelloStreamReply (HelloRequest) returns (stream HelloReply) {}
+
+  // Internal helpers to generate serializers for the server and deserializers for the client
+  rpc _EncodeStatus (Status) returns (Empty) {}
+  rpc _EncodeBadRequest (BadRequest) returns (Empty) {}
+  rpc _DecodeStatus (Empty) returns (Status) {}
+  rpc _DecodeBadRequest (Empty) returns (BadRequest) {}
 }
 
 // The request message containing the user's name.
@@ -38,3 +44,25 @@ message HelloRequest {
 message HelloReply {
   string message = 1;
 }
+
+// Standard definitions for rich errors
+message Status {
+  int32 code = 1;
+  string message = 2;
+  repeated Any details = 3;
+}
+
+message Any {
+  string type_url = 1;
+  bytes value = 2;
+}
+
+message BadRequest {
+  message FieldViolation {
+    string field = 1;
+    string description = 2;
+  }
+  repeated FieldViolation field_violations = 1;
+}
+
+message Empty {}