Refactor runtimeversion to be a command instead of option

Signed-off-by: Mrunal Patel <mrunalp@gmail.com>

cmd/client/main.go

@@ -28,14 +28,20 @@ func main() {
 	app := cli.NewApp()
 	app.Name = "ocic"
 	app.Usage = "client for ocid"
-	app.Flags = []cli.Flag{
-		cli.StringFlag{
-			Name:  "runtimeversion",
-			Value: "715fec664d75c6b5cb5b12718458621d4b75df37",
-			Usage: "the version of the gPRC client API",
-		},
+
+	app.Commands = []cli.Command{
+		runtimeVersionCommand,
 	}
-	app.Action = func(cxt *cli.Context) error {
+
+	if err := app.Run(os.Args); err != nil {
+		log.Fatal(err)
+	}
+}
+
+var runtimeVersionCommand = cli.Command{
+	Name:  "runtimeversion",
+	Usage: "get runtime version information",
+	Action: func(context *cli.Context) error {
 		// Set up a connection to the server.
 		conn, err := grpc.Dial(address, grpc.WithInsecure())
 		if err != nil {
@@ -45,13 +51,12 @@ func main() {
 		client := pb.NewRuntimeServiceClient(conn)
 
 		// Test RuntimeServiceClient.Version
-		err = Version(client, cxt.String("runtimeversion"))
+		version := "v1alpha1"
+		err = Version(client, version)
 		if err != nil {
-			log.Fatalf("%s.Version failed: %v", app.Name, err)
+			log.Fatalf("Getting the runtime version failed: %v", err)
 		}
 
 		return nil
-	}
-
-	app.Run(os.Args)
+	},
 }

server/server.go

@@ -1,9 +1,6 @@
 package server
 
 import (
-	"errors"
-	"strings"
-
 	pb "github.com/kubernetes/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
 	"golang.org/x/net/context"
 )
@@ -20,13 +17,6 @@ func (s *Server) Version(ctx context.Context, req *pb.VersionRequest) (*pb.Versi
 		return nil, nil
 	}
 
-	// FIXME: the logic here may need to be changed. How to determine whether the client/server APIs are compatible?
-	if strings.Compare(version, *req.Version) != 0 {
-		return &pb.VersionResponse{
-			Version: &version,
-		}, errors.New("The version of the gRPC server API is different from the version of the gRPC client API.")
-	}
-
 	runtimeName := "runc"
 
 	runtimeVersion, err := execRuncVersion("runc", "-v")