Can't decode messages using goprotobuf - go

Question

I have the following proto file:
package dogs;
enum Breed {
terrier = 0;
shepherd = 1;
hound = 2;
};
message Dog {
required int64 nbLegs = 1;
optional int64 nbTeeth = 2 [default=24];
optional Breed breed = 3;
optional string name = 4;
}
And the following Go program written using the goprotobuf package. The program
reads a Varint from stdin in order to get the length of the encoded message,
reads that number of bytes from stdin into a buffer, and
attempts to unmarshal the buffer into a Dog.
--START CODE--
package main
import "bufio"
import "encoding/binary"
import "os"
import "log"
import "fmt"
import "dogs"
import "code.google.com/p/goprotobuf/proto"
func render(dog *dogs.Dog) string {
return fmt.Sprintf("Dog: %v %v %v %v", dog.GetName(), dog.GetBreed(), dog.GetNbLegs(), dog.GetNbTeeth())
}
func main() {
var dog = new(dogs.Dog)
stdin := bufio.NewReader(os.Stdin)
sz, _ := binary.ReadVarint(stdin)
bytes := make([]byte, sz)
os.Stdin.Read(bytes)
buf := proto.NewBuffer(bytes)
err := buf.Unmarshal(dog)
if err != nil {
log.Fatal(err)
}
fmt.Fprintf(os.Stderr, "Receiving %s of length %d\n", render(dog), sz)
}
--END CODE--
And the this encoded message (preceded by a Varint) (in hexdump form)
0000000: 1408 0418 0222 0446 6964 6f .....".Fido
which i can successfully decode using c++ and libprotobuf as a Dog with
name: Fido
breed: hound
nbLegs: 4
nbTeeth: 24
Unmarshaling in the go program, however, always returns the error "illegal tag 0".
I suspect that I've misunderstood the decoding API but, so far, I can't see how.

Answer 1

Try just umarshalling the bytes instead of creating a buffer like this:
You may also want to check to see if os.Stdin.Read(bytes) is actually reading sz.
func main() {
var dog = new(dogs.Dog)
stdin := bufio.NewReader(os.Stdin)
sz, _ := binary.ReadVarint(stdin)
bytes := make([]byte, sz)
stdin.Read(bytes)
err := buf.Unmarshal(dog, bytes)
if err != nil {
log.Fatal(err)
}
fmt.Fprintf(os.Stderr, "Receiving %s of length %d\n", render(dog), sz)
}