Error: Illegal wire type for field Message.Field .protobuf.MessageTypeAck.sourceModuleID: 1 (0 expected)

问题:

I've app that procude&consume message with kafka and protocol buffer and everything works great. I'm serialize the protocol buffer with SerializeAsString() (this app was written in c++).

Now, I've added new node.js website that also consume messages and try to decode them.

My js code (using the great ProtoBuf.js module):

var builder = ProtoBuf.loadProtoFile("/home/aii/general/proto/All.proto"),     protobuf = builder.build("protobuf"),     Trace = protobuf.Trace,     MessageType = protobuf.MessageType,     MessageTypeAck = protobuf.MessageTypeAck,     MessageTypeKeepAlive = protobuf.MessageTypeKeepAlive;  function getMessageType(val) {   return Object.keys(MessageType).filter(function(key) {return MessageType[key] === val})[0] }  consumer.on('message', function (message) {     try{       switch(getMessageType(message.key[0])) {         case 'MESSAGE_TYPE_ACK':           console.log(MessageTypeAck.decode(message.value));           break;         case 'MESSAGE_TYPE_KEEP_ALIVE':           console.log(MessageTypeKeepAlive.decode(message.value));           break;         default:           console.log("Unknown message type");       }     } catch (e){       if (e.decoded) {         var err = e.decoded;         console.log(err);       }       else {         console.log(e);       }     } }); 

Result:

[Error: Illegal wire type for field Message.Field .protobuf.MessageTypeAck.sourceModuleID: 1 (0 expected)] 

My proto files:

Trace.proto:

package protobuf;  message Trace {     optional string topic = 1;     optional int32 partition = 2;     optional int64 offset = 3; } 

MessageType.proto

package protobuf;  enum MessageType {     MESSAGE_TYPE_ACK = 1;     MESSAGE_TYPE_KEEP_ALIVE = 2; } 

Messages.proto:

import "Trace.proto";  package protobuf;  message MessageTypeAck {     repeated Trace trace = 1;      optional string sourceModuleName = 2;     optional int32  sourceModuleID   = 3; }  message MessageTypeKeepAlive {     repeated Trace trace = 1;      optional string sourceModuleName = 2;     optional int32  sourceModuleID   = 3; } 

All.proto

import "Trace.proto" import "MessageType.proto"; import "Messages.proto" 

What am I doing wrong? (decode?)

回答1:

so, Thanks to this SO question&answer, I figured it out! The problem is related to the way I've consume the buffer (by kafka) - as utf-8 (default). It actually related to code which I didn't attached:

var kafka = require('kafka-node'),     Consumer = kafka.Consumer,     client = new kafka.Client('localhost:2181'),     consumer = new Consumer(         client,         [             { topic: 'Genesis', partition: 0 }         ],         {             autoCommit: false,             encoding: 'buffer'         }     );  

and the solution was to add the encoding: 'buffer' line (the default is 'utf-8' as mentioned here).

文章来源: Error: Illegal wire type for field Message.Field .protobuf.MessageTypeAck.sourceModuleID: 1 (0 expected)