How to use grpc connection pool in gokit?

[ryanking8215]

As far as I know, examples of gokit doesn't use grpc connection pool, it simpley uses grpc.Dial() in example apigateway.

As we know that connection pool generally provides the api like 'Unhealthy() or Unusable()' to mark the connection is unusable this turn and should not be put back to pool. My question is how to do the marking job in gokit?

I tried to find a way to do that, but I am not sure it is the proper way and wonder there is a better method to do the marking job.

Here is my way.

conn := pool.Get()

// finalize func do the mark and close thing
func myConnFinalizerFunc(ctx context.Context, err error) {
   conn := ctx.Value("conn");   
    if err!=nil && /* err is grpc connection error */ {
     conn.Unusable() // mark unusable
  }
   conn.Close()  // close anyway, means put back to pool.
}

var options []grpctransport.ClientOption
options = append(options, grpctransport.ClientFinalizer(myConnFinalizerFunc))

ep :=  grpctransport.NewClient(
			conn,
			"pb.OrderSvc",
			"Find",
			encodeFindRequest,
			decodeFindResponse,
			orderpb.FindReply{},
			append(options, grpctransport.ClientBefore(func(ctx context.Context, md) context.Context {
                                     return context.WithValue(ctx, "conn", conn)
                         }))...
		).Endpoint()

1. use 'ClientBefore' func to inject the 'conn' to ctx.
2. use 'ClientFinalizer' func to handle the error and get the conn from the ctx which we did in step 1.

Is this the proper way or there is another grace one?