Feat: add loggie version sub command (#508)

cmd/subcmd/switch.go

@@ -19,6 +19,7 @@ package subcmd
 import (
 	"github.com/loggie-io/loggie/cmd/subcmd/genfiles"
 	"github.com/loggie-io/loggie/cmd/subcmd/inspect"
+	"github.com/loggie-io/loggie/cmd/subcmd/version"
 	"os"
 )
 
@@ -36,6 +37,11 @@ func SwitchSubCommand() error {
 		if err := genfiles.RunGenFiles(); err != nil {
 			return err
 		}
+
+	case version.SubCommandVersion:
+		if err := version.RunVersion(); err != nil {
+			return err
+		}
 	}
 
 	return nil

cmd/subcmd/version/version.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2023 Loggie 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 version
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"github.com/loggie-io/loggie/pkg/core/global"
+	"os"
+)
+
+const (
+	SubCommandVersion = "version"
+)
+
+var (
+	versionCmd *flag.FlagSet
+)
+
+func init() {
+	versionCmd = flag.NewFlagSet(SubCommandVersion, flag.ExitOnError)
+}
+
+func RunVersion() error {
+	if len(os.Args) > 2 {
+		if err := versionCmd.Parse(os.Args[2:]); err != nil {
+			return err
+		}
+	}
+
+	fmt.Printf("Loggie version: %s\n", global.GetVersion())
+	return errors.New("exit")
+}