[vtctldclient] Add legacy shim

go/cmd/vtctlclient/main.go

@@ -67,6 +67,10 @@ func main() {
 			logutil.LogEvent(logger, e)
 		})
 	if err != nil {
+		if strings.Contains(err.Error(), "flag: help requested") {
+			return
+		}
+
 		errStr := strings.Replace(err.Error(), "remote error: ", "", -1)
 		fmt.Printf("%s Error: %s\n", flag.Arg(0), errStr)
 		log.Error(err)

go/cmd/vtctldclient/internal/command/legacy_shim.go

@@ -0,0 +1,104 @@
+/*
+Copyright 2021 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package command
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"vitess.io/vitess/go/cmd/vtctldclient/cli"
+	"vitess.io/vitess/go/vt/log"
+	"vitess.io/vitess/go/vt/logutil"
+	"vitess.io/vitess/go/vt/vtctl/vtctlclient"
+
+	logutilpb "vitess.io/vitess/go/vt/proto/logutil"
+)
+
+var (
+	// LegacyVtctlCommand provides a shim to make legacy ExecuteVtctlCommand
+	// RPCs. This allows users to use a single binary to make RPCs against both
+	// the new and old vtctld gRPC APIs.
+	LegacyVtctlCommand = &cobra.Command{
+		Use:   "LegacyVtctlCommand -- <command> [flags ...] [args ...]",
+		Short: "Invoke a legacy vtctlclient command. Flag parsing is best effort.",
+		Args:  cobra.ArbitraryArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cli.FinishedParsing(cmd)
+			return runLegacyCommand(args)
+		},
+		Long: strings.TrimSpace(`
+LegacyVtctlCommand uses the legacy vtctl grpc client to make an ExecuteVtctlCommand
+rpc to a vtctld.
+
+This command exists to support a smooth transition of any scripts that relied on
+vtctlclient during the migration to the new vtctldclient, and will be removed,
+following the Vitess project's standard deprecation cycle, once all commands
+have been migrated to the new VtctldServer api.
+
+To see the list of available legacy commands, run "LegacyVtctlCommand -- help".
+Note that, as with the old client, this requires a running server, as the flag
+parsing and help/usage text generation, is done server-side.
+
+Also note that, in order to defer that flag parsing to the server side, you must
+use the double-dash ("--") after the LegacyVtctlCommand subcommand string, or
+the client-side flag parsing library we are using will attempt to parse those
+flags (and fail).
+`),
+		Example: strings.TrimSpace(`
+LegacyVtctlCommand help # displays this help message
+LegacyVtctlCommand -- help # displays help for supported legacy vtctl commands
+
+# When using legacy command that take arguments, a double dash must be used
+# before the first flag argument, like in the first example. The double dash may
+# be used, however, at any point after the "LegacyVtctlCommand" string, as in
+# the second example.
+LegacyVtctlCommand AddCellInfo -- -server_address "localhost:1234" -root "/vitess/cell1"
+LegacyVtctlCommand -- AddCellInfo -server_address "localhost:5678" -root "/vitess/cell1"`),
+	}
+)
+
+func runLegacyCommand(args []string) error {
+	// Duplicated (mostly) from go/cmd/vtctlclient/main.go.
+	logger := logutil.NewConsoleLogger()
+
+	ctx, cancel := context.WithTimeout(context.Background(), actionTimeout)
+	defer cancel()
+
+	err := vtctlclient.RunCommandAndWait(ctx, server, args, func(e *logutilpb.Event) {
+		logutil.LogEvent(logger, e)
+	})
+	if err != nil {
+		if strings.Contains(err.Error(), "flag: help requested") {
+			// Help is caught by SetHelpFunc, so we don't want to indicate this as an error.
+			return nil
+		}
+
+		errStr := strings.Replace(err.Error(), "remote error: ", "", -1)
+		fmt.Printf("%s Error: %s\n", flag.Arg(0), errStr)
+		log.Error(err)
+	}
+
+	return err
+}
+
+func init() {
+	Root.AddCommand(LegacyVtctlCommand)
+}

go/cmd/vtctldclient/internal/command/root.go

@@ -25,7 +25,6 @@ import (
 	"github.com/spf13/cobra"
 
 	"vitess.io/vitess/go/trace"
-	"vitess.io/vitess/go/vt/log"
 	"vitess.io/vitess/go/vt/vtctl/vtctldclient"
 )
 
@@ -44,9 +43,7 @@ var (
 		// command context for every command.
 		PersistentPreRunE: func(cmd *cobra.Command, args []string) (err error) {
 			traceCloser = trace.StartTracing("vtctldclient")
-			if server == "" {
-				err = errors.New("please specify -server <vtctld_host:vtctld_port> to specify the vtctld server to connect to")
-				log.Error(err)
+			if err := ensureServerArg(); err != nil {
 				return err
 			}
 
@@ -75,6 +72,17 @@ var (
 	}
 )
 
+var errNoServer = errors.New("please specify -server <vtctld_host:vtctld_port> to specify the vtctld server to connect to")
+
+// ensureServerArg validates that --server was passed to the CLI.
+func ensureServerArg() error {
+	if server == "" {
+		return errNoServer
+	}
+
+	return nil
+}
+
 func init() {
 	Root.PersistentFlags().StringVar(&server, "server", "", "server to use for connection")
 	Root.PersistentFlags().DurationVar(&actionTimeout, "action_timeout", time.Hour, "timeout for the total command")

go/cmd/vtctldclient/plugin_grpcvtctlclient.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2021 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+// Imports and registers the gRPC vtctl client.
+
+import (
+	_ "vitess.io/vitess/go/vt/vtctl/grpcvtctlclient"
+)

go/vt/vtctl/grpcclientcommon/dial_option.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2021 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package grpcclientcommon defines the flags shared by both grpcvtctlclient and
+// grpcvtctldclient.
+package grpcclientcommon
+
+import (
+	"flag"
+
+	"google.golang.org/grpc"
+
+	"vitess.io/vitess/go/vt/grpcclient"
+)
+
+var (
+	cert = flag.String("vtctld_grpc_cert", "", "the cert to use to connect")
+	key  = flag.String("vtctld_grpc_key", "", "the key to use to connect")
+	ca   = flag.String("vtctld_grpc_ca", "", "the server ca to use to validate servers when connecting")
+	name = flag.String("vtctld_grpc_server_name", "", "the server name to use to validate server certificate")
+)
+
+// SecureDialOption returns a grpc.DialOption configured to use TLS (or
+// insecure if no flags were set) based on the vtctld_grpc_* flags declared by
+// this package.
+func SecureDialOption() (grpc.DialOption, error) {
+	return grpcclient.SecureDialOption(*cert, *key, *ca, *name)
+}

go/vt/vtctl/grpcvtctlclient/client.go

@@ -18,7 +18,6 @@ limitations under the License.
 package grpcvtctlclient
 
 import (
-	"flag"
 	"time"
 
 	"context"
@@ -27,27 +26,21 @@ import (
 
 	"vitess.io/vitess/go/vt/grpcclient"
 	"vitess.io/vitess/go/vt/logutil"
+	"vitess.io/vitess/go/vt/vtctl/grpcclientcommon"
 	"vitess.io/vitess/go/vt/vtctl/vtctlclient"
 
 	logutilpb "vitess.io/vitess/go/vt/proto/logutil"
 	vtctldatapb "vitess.io/vitess/go/vt/proto/vtctldata"
 	vtctlservicepb "vitess.io/vitess/go/vt/proto/vtctlservice"
 )
 
-var (
-	cert = flag.String("vtctld_grpc_cert", "", "the cert to use to connect")
-	key  = flag.String("vtctld_grpc_key", "", "the key to use to connect")
-	ca   = flag.String("vtctld_grpc_ca", "", "the server ca to use to validate servers when connecting")
-	name = flag.String("vtctld_grpc_server_name", "", "the server name to use to validate server certificate")
-)
-
 type gRPCVtctlClient struct {
 	cc *grpc.ClientConn
 	c  vtctlservicepb.VtctlClient
 }
 
 func gRPCVtctlClientFactory(addr string) (vtctlclient.VtctlClient, error) {
-	opt, err := grpcclient.SecureDialOption(*cert, *key, *ca, *name)
+	opt, err := grpcclientcommon.SecureDialOption()
 	if err != nil {
 		return nil, err
 	}

go/vt/vtctl/grpcvtctldclient/client.go

@@ -19,34 +19,17 @@ limitations under the License.
 package grpcvtctldclient
 
 import (
-	"flag"
-
 	"google.golang.org/grpc"
 
 	"vitess.io/vitess/go/vt/grpcclient"
+	"vitess.io/vitess/go/vt/vtctl/grpcclientcommon"
 	"vitess.io/vitess/go/vt/vtctl/vtctldclient"
 
 	vtctlservicepb "vitess.io/vitess/go/vt/proto/vtctlservice"
 )
 
 const connClosedMsg = "grpc: the client connection is closed"
 
-// (TODO:@amason) - These flags match exactly the flags used in grpcvtctlclient.
-// If a program attempts to import both of these packages, it will panic during
-// startup due to the duplicate flags.
-//
-// For everything else I've been doing a sed s/vtctl/vtctld, but I cannot do
-// that here, since these flags are already "vtctld_*". My other options are to
-// name them "vtctld2_*" or to omit them completely.
-//
-// Not to pitch project ideas in comments, but a nice project to solve
-var (
-	cert = flag.String("vtctld_grpc_cert", "", "the cert to use to connect")
-	key  = flag.String("vtctld_grpc_key", "", "the key to use to connect")
-	ca   = flag.String("vtctld_grpc_ca", "", "the server ca to use to validate servers when connecting")
-	name = flag.String("vtctld_grpc_server_name", "", "the server name to use to validate server certificate")
-)
-
 type gRPCVtctldClient struct {
 	cc *grpc.ClientConn
 	c  vtctlservicepb.VtctldClient
@@ -56,7 +39,7 @@ type gRPCVtctldClient struct {
 //go:generate grpcvtctldclient -out client_gen.go
 
 func gRPCVtctldClientFactory(addr string) (vtctldclient.VtctldClient, error) {
-	opt, err := grpcclient.SecureDialOption(*cert, *key, *ca, *name)
+	opt, err := grpcclientcommon.SecureDialOption()
 	if err != nil {
 		return nil, err
 	}