praefect: Remove old sub-command implementation leftovers

All sub-commands of Praefect were moved to a third party
urfave/cli/v2 library. The old helper functions and an interface
are removed as they are not used anymore.
Also, the help text generated by new library now contains information
about all sub-commands and doesn't need to be modified.
The 'serve' sub-command can now be restricted to disallow arguments
to be passed for it.

Part of: #5001

3 files changed, 6 insertions, 81 deletions

diff --git a/internal/cli/praefect/main.go b/internal/cli/praefect/main.go
index 874a2cac0..1b2ec299e 100644
--- a/internal/cli/praefect/main.go
+++ b/internal/cli/praefect/main.go
@@ -15,8 +15,6 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"sort"
-	"strings"
 
 	"github.com/urfave/cli/v2"
 	"gitlab.com/gitlab-org/gitaly/v16/internal/praefect/service"
@@ -80,7 +78,6 @@ func NewApp() *cli.App {
 				Usage: "load configuration from `FILE`",
 			},
 		},
-		CustomAppHelpTemplate: helpTextTemplate(),
 	}
 }
 
@@ -100,22 +97,3 @@ func mustProvideConfigFlag(ctx *cli.Context, command string) string {
 
 	return pathToConfigFile
 }
-
-func helpTextTemplate() string {
-	var cmds []string
-	for k := range subcommands(nil) {
-		cmds = append(cmds, k)
-	}
-	sort.Strings(cmds)
-
-	// Because not all sub-commands are registered with the new approach they won't be shown
-	// with the -help. To have them in the output we inject a simple list of their names into
-	// the template to have them presented.
-	return strings.Replace(
-		cli.AppHelpTemplate,
-		`COMMANDS:{{template "visibleCommandCategoryTemplate" .}}{{end}}`,
-		`COMMANDS:{{template "visibleCommandCategoryTemplate" .}}{{end}}`+
-			"\n   "+strings.Join(cmds, "\n   "),
-		1,
-	)
-}
diff --git a/internal/cli/praefect/serve.go b/internal/cli/praefect/serve.go
index 328459ef6..7e5b93a3e 100644
--- a/internal/cli/praefect/serve.go
+++ b/internal/cli/praefect/serve.go
@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"math/rand"
 	"net/http"
-	"os"
 	"runtime/debug"
 	"time"
 
@@ -47,26 +46,17 @@ func newServeCommand() *cli.Command {
 		Usage:           "launch the server daemon",
 		Action:          serveAction,
 		HideHelpCommand: true,
+		Before: func(context *cli.Context) error {
+			if context.Args().Present() {
+				return unexpectedPositionalArgsError{Command: context.Command.Name}
+			}
+			return nil
+		},
 	}
 }
 
 func serveAction(ctx *cli.Context) error {
 	logger := log.Default()
-	// In order to support execution of all sub-commands not yet migrated to use a new cli
-	// implementation the invocation is done manually here.
-	subCmd := ctx.Args().First()
-	if subCmd != "" {
-		// It doesn't make difference if we provide command name to the invocation below
-		// or not as there won't be any output printed, because sub-commands are not yet
-		// registered.
-		pathToConfigFile := mustProvideConfigFlag(ctx, "")
-		conf, err := getConfig(logger, pathToConfigFile)
-		if err != nil {
-			return err
-		}
-		os.Exit(subCommand(conf, logger, subCmd, ctx.Args().Slice()[1:]))
-	}
-
 	// The ctx.Command.Name can't be used here because if `praefect -config FILE` is used
 	// it will be set to 'praefect' instead of 'serve'.
 	pathToConfigFile := mustProvideConfigFlag(ctx, "serve")
diff --git a/internal/cli/praefect/subcmd.go b/internal/cli/praefect/subcmd.go
index 2767c4b42..537edaea9 100644
--- a/internal/cli/praefect/subcmd.go
+++ b/internal/cli/praefect/subcmd.go
@@ -4,13 +4,10 @@ import (
 	"context"
 	"database/sql"
 	"errors"
-	"flag"
 	"fmt"
 	"os"
-	"os/signal"
 	"time"
 
-	"github.com/sirupsen/logrus"
 	gitalyauth "gitlab.com/gitlab-org/gitaly/v16/auth"
 	"gitlab.com/gitlab-org/gitaly/v16/client"
 	internalclient "gitlab.com/gitlab-org/gitaly/v16/internal/grpc/client"
@@ -19,11 +16,6 @@ import (
 	"google.golang.org/grpc"
 )
 
-type subcmd interface {
-	FlagSet() *flag.FlagSet
-	Exec(flags *flag.FlagSet, config config.Config) error
-}
-
 const (
 	defaultDialTimeout        = 10 * time.Second
 	paramVirtualStorage       = "virtual-storage"
@@ -31,41 +23,6 @@ const (
 	paramAuthoritativeStorage = "authoritative-storage"
 )
 
-func subcommands(logger *logrus.Entry) map[string]subcmd {
-	return map[string]subcmd{}
-}
-
-// subCommand returns an exit code, to be fed into os.Exit.
-func subCommand(conf config.Config, logger *logrus.Entry, arg0 string, argRest []string) int {
-	interrupt := make(chan os.Signal, 1)
-	signal.Notify(interrupt, os.Interrupt)
-
-	go func() {
-		<-interrupt
-		os.Exit(130) // indicates program was interrupted
-	}()
-
-	subcmd, ok := subcommands(logger)[arg0]
-	if !ok {
-		printfErr("%s: unknown subcommand: %q\n", progname, arg0)
-		return 1
-	}
-
-	flags := subcmd.FlagSet()
-
-	if err := flags.Parse(argRest); err != nil {
-		printfErr("%s\n", err)
-		return 1
-	}
-
-	if err := subcmd.Exec(flags, conf); err != nil {
-		printfErr("%s\n", err)
-		return 1
-	}
-
-	return 0
-}
-
 func getNodeAddress(cfg config.Config) (string, error) {
 	switch {
 	case cfg.SocketPath != "":