Add go:generate and move generated code to internal

gen-go/meta/tchan-meta.go → internal/gen-go/meta/tchan-meta.go

@@ -42,6 +42,10 @@ func (c *tchanMetaClient) Health(ctx thrift.Context) (*HealthStatus, error) {
 	args := MetaHealthArgs{}
 	success, err := c.client.Call(ctx, c.thriftService, "health", &args, &resp)
 	if err == nil && !success {
+		switch {
+		default:
+			err = fmt.Errorf("received no result or unknown exception for health")
+		}
 	}
 
 	return resp.GetSuccess(), err
@@ -52,6 +56,10 @@ func (c *tchanMetaClient) ThriftIDL(ctx thrift.Context) (string, error) {
 	args := MetaThriftIDLArgs{}
 	success, err := c.client.Call(ctx, c.thriftService, "thriftIDL", &args, &resp)
 	if err == nil && !success {
+		switch {
+		default:
+			err = fmt.Errorf("received no result or unknown exception for thriftIDL")
+		}
 	}
 
 	return resp.GetSuccess(), err

tcheck.go

@@ -28,12 +28,14 @@ import (
 	"strings"
 	"time"
 
-	"github.com/uber/tcheck/gen-go/meta"
+	"github.com/uber/tcheck/internal/gen-go/meta"
 
 	"github.com/uber/tchannel-go"
 	"github.com/uber/tchannel-go/thrift"
 )
 
+//go:generate thrift-gen --generateThrift --inputFile meta.thrift --outputDir ./internal/gen-go
+
 const (
 	_serviceName = "tcheck"