grpc-tolua

unity grpc for lua using tolua

(Work In Progress)

With grpc-tolua, you can use grpc in Lua in Unity.

It uses tolua to bind Unity C# and Lua.

• only grpc client, no server

Usage example

See Examples/RouteGuide

local grpctolua = require('grpctolua')

local channel = grpctolua.new_channel('localhost:50051')
local client = grpctolua.new_client(channel, 'routeguide.RouteGuide')

grpctolua.load_descriptor_set_from_file('route_guide.pb')

function TestGetFeature()
    coroutine.start(CoGetFeature)
end

function TestListFeatures()
    coroutine.start(CoListFeatures)
end

function TestRecordRoute()
    coroutine.start(CoRecordRoute)
end

function TestRouteChat()
    coroutine.start(CoRouteChat)
end

function CoGetFeature()
    local feature = client:await_call('GetFeature', GetPoint(409146138, -746188906))
    print('feature: '..DumpTable(feature))
end

function CoListFeatures()
    local req = {lo = GetPoint(400000000, -750000000), hi = GetPoint(420000000, -730000000)}
    local call = client:call('ListFeatures', req)
    call:wait_for_each_response(function(rsp)
        print(DumpTable(rsp))
    end)
end

function CoRecordRoute()
    local call = client:call('RecordRoute')
    coroutine.start(function()
        local rsp = call:wait_for_response()
        print('RecordRoute resonse: '..DumpTable(rsp))
    end)
    
    local features = GetFeatures()
    for _, f in ipairs(features) do
        print('call:await_write(location)...')
        call:await_write(f.location)
    end
    call:await_complete()
end

function CoRouteChat()
    local call = client:call('RouteChat')
    coroutine.start(function() CoPrintResponses(call) end)
    
    local notes = GetRouteNotes()
    for _, n in ipairs(notes) do
        call:await_write(n)
    end
    call:await_complete()
end

function CoPrintResponses(call)
    call:wait_for_each_response(function(rsp)
        print('RouteChat response: '..DumpTable(rsp))
    end)
end

How to run example

1. Copy grpc_unity_package into Assets dir
   • https://github.com/grpc/grpc/tree/master/src/csharp/experimental#unity
2. Open Assets\GrpcToLua\Examples\RouteGuide\RouteGuide.unity
3. Menu: Lua -> Generate All
4. Run a server on port 50051. For example go server
5. Play

It can only run on Windows 64 because only Plugins\x86_64\tolua.dll is updated to support lua-protobuf. On other platforms it will be error with: attempt to call field 'load' (a nil value). Please Integrate starwing/lua-protobuf for other platforms.

How to update

1. Update grpc_unity_package
2. Update to the latest tolua
   • Copy Assets, Unity5.x, Luajit64, Luajit from tolua
   • Copy coroutine.wait_until(conditionFunc, co) from https://github.com/woshihuo12/tolua
     • See commit 441d9f
3. Integrate starwing/lua-protobuf
   • Update plugins
     • only Plugins\x86_64\tolua.dll is lua-protobuf ready
4. Add in Assets\Editor\Custom\CustomSetting.cs customTypeList

   public static BindType[] customTypeList =
   {
   	...
       // GrpcToLua
       _GT(typeof(Grpc.Core.Channel)),
       _GT(typeof(Grpc.Core.ChannelCredentials)),
       _GT(typeof(Grpc.Core.Status)),
       _GT(typeof(GrpcToLua.AsyncUnaryCall)),
       _GT(typeof(GrpcToLua.AsyncServerStreamingCall)),
       _GT(typeof(GrpcToLua.AsyncClientStreamingCall)),
       _GT(typeof(GrpcToLua.AsyncDuplexStreamingCall)),
       _GT(typeof(GrpcToLua.Client)),
       _GT(typeof(GrpcToLua.DescriptorSetLoader)),
       _GT(typeof(GrpcToLua.InsecureCredentials)),
       _GT(typeof(System.Runtime.CompilerServices.TaskAwaiter)),
       _GT(typeof(System.Runtime.CompilerServices.TaskAwaiter<byte[]>)),
       _GT(typeof(System.Threading.Tasks.Task<byte[]>)),
   }
   

5. Add in Assets\ToLua\Editor\ToLuaExport.cs memberFilter

   public static List<string> memberFilter = new List<string>
   {
       "Task.IsCompletedSuccessfully",
       ...
   }
   

Trouble Shooting

module 'grpctolua' not found

Make sure to add lua search path like this:

    lua = new LuaState();
    lua.AddSearchPath(Application.dataPath + "/GrpcToLua/Lua");

module 'pb' not found

Make sure pb is opened:

    lua.OpenLibs(LuaDLL.luaopen_pb);

attempt to call field 'load' (a nil value)

Use starwing/lua-protobuf