replace command line parser (#1383)

go.mod

@@ -5,6 +5,7 @@ go 1.18
 require (
 	code.cloudfoundry.org/bytefmt v0.0.0
 	github.com/abema/go-mp4 v0.9.0
+	github.com/alecthomas/kong v0.7.1
 	github.com/aler9/gortsplib/v2 v2.0.5
 	github.com/asticode/go-astits v1.10.1-0.20220319093903-4abe66a9b757
 	github.com/fsnotify/fsnotify v1.4.9
@@ -22,13 +23,10 @@ require (
 	github.com/pion/webrtc/v3 v3.1.47
 	github.com/stretchr/testify v1.7.1
 	golang.org/x/crypto v0.0.0-20221010152910-d6f0a8c073c2
-	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 	gopkg.in/yaml.v2 v2.4.0
 )
 
 require (
-	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751 // indirect
-	github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d // indirect
 	github.com/asticode/go-astikit v0.20.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gin-contrib/sse v0.1.0 // indirect

go.sum

@@ -1,9 +1,9 @@
 github.com/abema/go-mp4 v0.9.0 h1:WFkzn0J8uYTQ2MIWfgCaFHRB3VDkird5JncIjuuKjGI=
 github.com/abema/go-mp4 v0.9.0/go.mod h1:vPl9t5ZK7K0x68jh12/+ECWBCXoWuIDtNgPtU2f04ws=
-github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751 h1:JYp7IbQjafoB+tBA3gMyHYHrpOtNuDiK/uB5uXxq5wM=
-github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
-github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d h1:UQZhZ2O0vMHr2cI+DC1Mbh0TJxzA3RcLoMsFw+aXw7E=
-github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
+github.com/alecthomas/assert/v2 v2.1.0 h1:tbredtNcQnoSd3QBhQWI7QZ3XHOVkw1Moklp2ojoH/0=
+github.com/alecthomas/kong v0.7.1 h1:azoTh0IOfwlAX3qN9sHWTxACE2oV8Bg2gAwBsMwDQY4=
+github.com/alecthomas/kong v0.7.1/go.mod h1:n1iCIO2xS46oE8ZfYCNDqdR0b0wZNrXAIAqro/2132U=
+github.com/alecthomas/repr v0.1.0 h1:ENn2e1+J3k09gyj2shc0dHr/yjaWSHRlrJ4DPMevDqE=
 github.com/aler9/gortsplib/v2 v2.0.5 h1:K1dxSVMCRB22tNcpqAjSQBHj6YoIp2ad0FakEJAe+lo=
 github.com/aler9/gortsplib/v2 v2.0.5/go.mod h1:cGD/4JW43Elv/f4HfNBdH78IO5ZfwZIY52fByVASmsU=
 github.com/aler9/writerseeker v0.0.0-20220601075008-6f0e685b9c82 h1:9WgSzBLo3a9ToSVV7sRTBYZ1GGOZUpq4+5H3SN0UZq4=
@@ -61,6 +61,7 @@ github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWm
 github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/grafov/m3u8 v0.11.1 h1:igZ7EBIB2IAsPPazKwRKdbhxcoBKO3lO1UY57PZDeNA=
 github.com/grafov/m3u8 v0.11.1/go.mod h1:nqzOkfBiZJENr52zTVd/Dcl03yzphIMbJqkXGu+u080=
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/json-iterator/go v1.1.12 h1:PV8peI4a0ysnczrg+LtxykD8LfKY9ML6u2jnxaEnrnM=
 github.com/json-iterator/go v1.1.12/go.mod h1:e30LSqwooZae/UwlEbR2852Gd8hjQvJoHmT4TnhNGBo=
@@ -237,8 +238,6 @@ google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp0
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.28.0 h1:w43yiav+6bVFTBQFZX0r7ipe9JQ1QsbMgHwbBziscLw=
 google.golang.org/protobuf v1.28.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
-gopkg.in/alecthomas/kingpin.v2 v2.2.6 h1:jMFz6MfLP0/4fUyZle81rXUoxOBFi19VUFKVDOQfozc=
-gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/core/core.go

@@ -8,9 +8,9 @@ import (
 	"os/signal"
 	"reflect"
 
+	"github.com/alecthomas/kong"
 	"github.com/aler9/gortsplib/v2"
 	"github.com/gin-gonic/gin"
-	"gopkg.in/alecthomas/kingpin.v2"
 
 	"github.com/aler9/rtsp-simple-server/internal/conf"
 	"github.com/aler9/rtsp-simple-server/internal/confwatcher"
@@ -49,17 +49,32 @@ type Core struct {
 	done chan struct{}
 }
 
+var cli struct {
+	Version  bool   `help:"print version"`
+	Confpath string `arg:"" default:"rtsp-simple-server.yml"`
+}
+
 // New allocates a core.
 func New(args []string) (*Core, bool) {
-	k := kingpin.New("rtsp-simple-server", "rtsp-simple-server "+version)
-
-	argVersion := k.Flag("version", "print version").Bool()
-	argConfPath := k.Arg("confpath", "path to a config file. The default is rtsp-simple-server.yml.").
-		Default("rtsp-simple-server.yml").String()
-
-	kingpin.MustParse(k.Parse(args))
+	parser, err := kong.New(&cli,
+		kong.Description("rtsp-simple-server "+version),
+		kong.UsageOnError(),
+		kong.ValueFormatter(func(value *kong.Value) string {
+			switch value.Name {
+			case "confpath":
+				return "path to a config file. The default is rtsp-simple-server.yml."
+
+			default:
+				return kong.DefaultHelpValueFormatter(value)
+			}
+		}))
+	if err != nil {
+		panic(err)
+	}
+	_, err = parser.Parse(args)
+	parser.FatalIfErrorf(err)
 
-	if *argVersion {
+	if cli.Version {
 		fmt.Println(version)
 		os.Exit(0)
 	}
@@ -76,12 +91,11 @@ func New(args []string) (*Core, bool) {
 	p := &Core{
 		ctx:            ctx,
 		ctxCancel:      ctxCancel,
-		confPath:       *argConfPath,
+		confPath:       cli.Confpath,
 		chAPIConfigSet: make(chan *conf.Conf),
 		done:           make(chan struct{}),
 	}
 
-	var err error
 	p.conf, p.confFound, err = conf.Load(p.confPath)
 	if err != nil {
 		fmt.Printf("ERR: %s\n", err)