servenv: Remove double close() logic

The servenv.Run function already runs the close hooks once it finishes.
This means there's no use for deferring a `.Close()` since it double
executes all close hooks.

In fact, it leads to panics. For example, vttablet always panics on each
shutdown because the connection to the topo is already closed.

Signed-off-by: Dirkjan Bussink <[email protected]>

go/cmd/mysqlctld/cli/mysqlctld.go

@@ -54,7 +54,6 @@ var (
 		Long: "`mysqlctld` is a gRPC server that can be used instead of the `mysqlctl` client tool.\n" +
 			"If the target directories are empty when it is invoked, it automatically performs initialization operations to bootstrap the `mysqld` instance before starting it.\n" +
 			"The `mysqlctld` process can subsequently receive gRPC commands from a `vttablet` to perform housekeeping operations like shutting down and restarting the `mysqld` instance as needed.\n\n" +
-
 			"{{< warning >}}\n" +
 			"`mysqld_safe` is not used so the `mysqld` process will not be automatically restarted in case of a failure.\n" +
 			"{{</ warning>}}\n\n" +
@@ -151,7 +150,6 @@ func run(cmd *cobra.Command, args []string) error {
 	cancel()
 
 	servenv.Init()
-	defer servenv.Close()
 
 	// Take mysqld down with us on SIGTERM before entering lame duck.
 	servenv.OnTermSync(func() {

go/cmd/vtaclcheck/cli/vtactlcheck.go

@@ -44,7 +44,6 @@ var (
 
 func run(cmd *cobra.Command, args []string) error {
 	servenv.Init()
-	defer servenv.Close()
 
 	opts := &vtaclcheck.Options{
 		ACLFile:        aclFile,

go/cmd/vtbackup/cli/vtbackup.go

@@ -217,7 +217,6 @@ func init() {
 
 func run(_ *cobra.Command, args []string) error {
 	servenv.Init()
-	defer servenv.Close()
 
 	ctx, cancel := context.WithCancel(context.Background())
 	servenv.OnClose(func() {

go/cmd/vtbench/cli/vtbench.go

@@ -162,7 +162,6 @@ func run(cmd *cobra.Command, args []string) error {
 	_ = cmd.Flags().Set("logtostderr", "true")
 
 	servenv.Init()
-	defer servenv.Close()
 
 	var clientProto vtbench.ClientProtocol
 	switch protocol {

go/cmd/vtctld/cli/cli.go

@@ -55,7 +55,6 @@ This is demonstrated in the example usage below.`,
 
 func run(cmd *cobra.Command, args []string) error {
 	servenv.Init()
-	defer servenv.Close()
 
 	ts = topo.Open()
 	defer ts.Close()

go/cmd/vtgate/cli/cli.go

@@ -134,7 +134,6 @@ func run(cmd *cobra.Command, args []string) error {
 	defer exit.Recover()
 
 	servenv.Init()
-	defer servenv.Close()
 
 	ts := topo.Open()
 	defer ts.Close()

go/cmd/vttablet/cli/cli.go

@@ -104,7 +104,6 @@ vttablet \
 
 func run(cmd *cobra.Command, args []string) error {
 	servenv.Init()
-	defer servenv.Close()
 
 	tabletAlias, err := topoproto.ParseTabletAlias(tabletPath)
 	if err != nil {

go/vt/servenv/run.go

@@ -18,7 +18,6 @@ package servenv
 
 import (
 	"net"
-	"net/url"
 	"os"
 	"os/signal"
 	"strconv"
@@ -76,12 +75,6 @@ func Run(bindAddress string, port int) {
 	fireOnCloseHooks(onCloseTimeout)
 }
 
-// Close runs any registered exit hooks in parallel.
-func Close() {
-	onCloseHooks.Fire()
-	ListeningURL = url.URL{}
-}
-
 // OnClose registers f to be run at the end of the app lifecycle.
 // This happens after the lameduck period just before the program exits.
 // All hooks are run in parallel.