add positional argument validation

go/cmd/automation_server/automation_server.go

@@ -17,7 +17,6 @@ limitations under the License.
 package main
 
 import (
- "flag"
  "fmt"
  "net"
  "os"
@@ -34,13 +33,7 @@ func init() {
 }
 
 func main() {
-
- flag.Parse()
-
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
+ servenv.ParseFlags("automation_server")
 
  fmt.Println("Automation Server, listening on:", *servenv.Port)
 

go/cmd/l2vtgate/main.go

@@ -19,7 +19,6 @@ package main
 import (
  "flag"
  "math/rand"
- "os"
  "strings"
  "time"
 
@@ -55,14 +54,9 @@ func init() {
 func main() {
  defer exit.Recover()
 
- flag.Parse()
+ servenv.ParseFlags("l2vtgate")
  servenv.Init()
 
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
  ts := topo.Open()
  defer ts.Close()
 

go/cmd/mysqlctld/mysqlctld.go

@@ -58,12 +58,7 @@ func main() {
  // mysqlctld only starts and stops mysql, only needs dba.
  dbconfigFlags := dbconfigs.DbaConfig
  dbconfigs.RegisterFlags(dbconfigFlags)
- flag.Parse()
-
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
+ servenv.ParseFlags("mysqlctld")
 
  // We'll register this OnTerm handler before mysqld starts, so we get notified
  // if mysqld dies on its own without us (or our RPC client) telling it to.

go/cmd/vtcombo/main.go

@@ -23,7 +23,6 @@ package main
 
 import (
  "flag"
- "os"
  "strings"
  "time"
 
@@ -67,18 +66,7 @@ func main() {
  dbconfigs.FilteredConfig | dbconfigs.ReplConfig
  dbconfigs.RegisterFlags(dbconfigFlags)
  mysqlctl.RegisterFlags()
- flag.Parse()
-
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
- if len(flag.Args()) > 0 {
- flag.Usage()
- log.Errorf("vtcombo doesn't take any positional arguments")
- exit.Return(1)
- }
+ servenv.ParseFlags("vtcombo")
 
  // parse the input topology
  tpb := &vttestpb.VTTestTopology{}

go/cmd/vtctl/vtctl.go

@@ -69,19 +69,7 @@ func main() {
  defer exit.RecoverAll()
  defer logutil.Flush()
 
- flag.Parse()
- args := flag.Args()
-
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
- if len(args) == 0 {
- flag.Usage()
- exit.Return(1)
- }
-
+ args := servenv.ParseFlagsWithArgs("vtctl")
  action := args[0]
 
  startMsg := fmt.Sprintf("USER=%v SUDO_USER=%v %v", os.Getenv("USER"), os.Getenv("SUDO_USER"), strings.Join(os.Args, " "))

go/cmd/vtctld/main.go

@@ -17,9 +17,6 @@ limitations under the License.
 package main
 
 import (
- "flag"
- "os"
-
  "github.com/youtube/vitess/go/vt/servenv"
  "github.com/youtube/vitess/go/vt/topo"
  "github.com/youtube/vitess/go/vt/vtctld"
@@ -35,15 +32,10 @@ var (
 )
 
 func main() {
- flag.Parse()
+ servenv.ParseFlags("vtctld")
  servenv.Init()
  defer servenv.Close()
 
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
  ts = topo.Open()
  defer ts.Close()
 

go/cmd/vtexplain/vtexplain.go

@@ -20,7 +20,6 @@ import (
  "flag"
  "fmt"
  "io/ioutil"
- "os"
 
  log "github.com/golang/glog"
  "github.com/youtube/vitess/go/exit"
@@ -124,19 +123,7 @@ func main() {
  defer exit.RecoverAll()
  defer logutil.Flush()
 
- flag.Parse()
-
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
- args := flag.Args()
-
- if len(args) != 0 {
- flag.Usage()
- exit.Return(1)
- }
+ servenv.ParseFlags("vtexplain")
 
  err := parseAndRun()
  if err != nil {

go/cmd/vtgate/vtgate.go

@@ -19,7 +19,6 @@ package main
 import (
  "flag"
  "math/rand"
- "os"
  "strings"
  "time"
 
@@ -59,14 +58,9 @@ func init() {
 func main() {
  defer exit.Recover()
 
- flag.Parse()
+ servenv.ParseFlags("vtgate")
  servenv.Init()
 
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
  if initFakeZK != nil {
  initFakeZK()
  }

go/cmd/vtgateclienttest/main.go

@@ -20,9 +20,6 @@ limitations under the License.
 package main
 
 import (
- "flag"
- "os"
-
  "github.com/youtube/vitess/go/cmd/vtgateclienttest/services"
  "github.com/youtube/vitess/go/exit"
  "github.com/youtube/vitess/go/vt/servenv"
@@ -36,14 +33,9 @@ func init() {
 func main() {
  defer exit.Recover()
 
- flag.Parse()
+ servenv.ParseFlags("vtgateclienttest")
  servenv.Init()
 
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
-
  // The implementation chain.
  servenv.OnRun(func() {
  s := services.CreateServices()

go/cmd/vttablet/vttablet.go

@@ -19,7 +19,6 @@ package main
 
 import (
  "flag"
- "os"
 
  log "github.com/golang/glog"
  "github.com/youtube/vitess/go/vt/dbconfigs"
@@ -52,17 +51,9 @@ func main() {
  dbconfigs.FilteredConfig | dbconfigs.ReplConfig
  dbconfigs.RegisterFlags(dbconfigFlags)
  mysqlctl.RegisterFlags()
- flag.Parse()
 
- if *servenv.Version {
- servenv.AppVersion.Print()
- os.Exit(0)
- }
+ servenv.ParseFlags("vttablet")
 
- if len(flag.Args()) > 0 {
- flag.Usage()
- log.Exit("vttablet doesn't take any positional arguments")
- }
  if err := tabletenv.VerifyConfig(); err != nil {
  log.Exitf("invalid config: %v", err)
  }

go/vt/servenv/servenv.go

@@ -33,6 +33,7 @@ import (
  "net/url"
  "os"
  "runtime"
+ "strings"
  "sync"
  "syscall"
  "time"
@@ -193,3 +194,37 @@ func RegisterDefaultFlags() {
 func RunDefault() {
  Run(*Port)
 }
+
+// ParseFlags initializes flags and handles the common case when no positional
+// arguments are expected.
+func ParseFlags(cmd string) {
+ flag.Parse()
+
+ if *Version {
+ AppVersion.Print()
+ os.Exit(0)
+ }
+
+ args := flag.Args()
+ if len(args) > 0 {
+ flag.Usage()
+ log.Exitf("%s doesn't take any positional arguments, got '%s'", cmd, strings.Join(args, " "))
+ }
+}
+
+// ParseFlagsWithArgs initializes flags and returns the positional arguments
+func ParseFlagsWithArgs(cmd string) []string {
+ flag.Parse()
+
+ if *Version {
+ AppVersion.Print()
+ os.Exit(0)
+ }
+
+ args := flag.Args()
+ if len(args) == 0 {
+ log.Exitf("%s expected at least one positional argument", cmd)
+ }
+
+ return args
+}