Error while compiling protocol buffer on mac

Question

I am following the tutorial for protocol buffers and I keep running into different errors while compiling. my addressbook.proto file is in /Users/flexmaster411/protobuffer

protoc -I=/Users/flexmaster411/protobuffer --python_out= /Users/flexmaster411/protobuffer/addressbook.proto /Users/flexmaster411/protobuffer

I keep getting the following error even though I have syntax = "proto3" on my proto file

[libprotobuf WARNING google/protobuf/compiler/parser.cc:471] No syntax specified for the proto file. Please use 'syntax = "proto2";' or 'syntax = "proto3";' to specify a syntax version. (Defaulted to proto2 syntax.)

Not sure if I have correctly done the destination folders set up which is causing this or not Any help appreciated

syntax = "proto3";

package tutorial;

message Person {
  string name = 1;
  int32 id = 2;        // Unique ID number for this person.
  string email = 3;

  enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
  }

  message PhoneNumber {
    string number = 1;
    PhoneType type = 2;
  }

  repeated PhoneNumber phones = 4;
}

// Our address book file is just one of these.
message AddressBook {
  repeated Person people = 1;
}

Answer 1

It looks like you reversed the order of the parameters. /Users/flexmaster411/protobuffer is your output directory, so it should appear with --python_out. Since you specified it second, protoc thinks you're telling it that /Users/flexmaster411/protobuffer is an input. So it's trying to open a directory and then parse it as a .proto file. Amusingly, read() on a directory returns no data, which protoc interprets as a perfectly valid .proto file that simply doesn't declare anything! But it then gives you a warning because this empty file doesn't have any syntax line.

I think what you meant to type is:

protoc -I=/Users/flexmaster411/protobuffer --python_out=/Users/flexmaster411/protobuffer /Users/flexmaster411/protobuffer/addressbook.proto