runtime: augment kata-runtime CLI to support direct-assigned volume

Add commands to add, remove, resize and get stats of a direct-assigned volume.
These commands are expected to be consumed by CSI.

Fixes: #3454

Signed-off-by: Feng Wang <feng.wang@databricks.com>

src/runtime/cmd/kata-runtime/kata-volume.go

@@ -0,0 +1,108 @@
+// Copyright (c) 2022 Databricks Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package main
+
+import (
+	"github.com/kata-containers/kata-containers/src/runtime/pkg/direct-volume"
+	"github.com/urfave/cli"
+)
+
+var volumeSubCmds = []cli.Command{
+	addCommand,
+	removeCommand,
+	statsCommand,
+	resizeCommand,
+}
+
+var (
+	mountInfo  string
+	volumePath string
+	size       uint64
+)
+
+var kataVolumeCommand = cli.Command{
+	Name:        "direct-volume",
+	Usage:       "directly assign a volume to Kata Containers to manage",
+	Subcommands: volumeSubCmds,
+	Action: func(context *cli.Context) {
+		cli.ShowSubcommandHelp(context)
+	},
+}
+
+var addCommand = cli.Command{
+	Name:  "add",
+	Usage: "add a direct assigned block volume device to the Kata Containers runtime",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:        "volume-path",
+			Usage:       "the target volume path the volume is published to",
+			Destination: &volumePath,
+		},
+		cli.StringFlag{
+			Name:        "mount-info",
+			Usage:       "the mount info for the Kata Containers runtime to manage the volume",
+			Destination: &mountInfo,
+		},
+	},
+	Action: func(c *cli.Context) error {
+		return volume.Add(volumePath, mountInfo)
+	},
+}
+
+var removeCommand = cli.Command{
+	Name:  "remove",
+	Usage: "remove a direct assigned block volume device from the Kata Containers runtime",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:        "volume-path",
+			Usage:       "the target volume path the volume is published to",
+			Destination: &volumePath,
+		},
+	},
+	Action: func(c *cli.Context) error {
+		return volume.Remove(volumePath)
+	},
+}
+
+var statsCommand = cli.Command{
+	Name:  "stats",
+	Usage: "get the filesystem stat of a direct assigned volume",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:        "volume-path",
+			Usage:       "the target volume path the volume is published to",
+			Destination: &volumePath,
+		},
+	},
+	Action: func(c *cli.Context) (string, error) {
+		stats, err := volume.Stats(volumePath)
+		if err != nil {
+			return "", err
+		}
+
+		return string(stats), nil
+	},
+}
+
+var resizeCommand = cli.Command{
+	Name:  "resize",
+	Usage: "resize a direct assigned block volume",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:        "volume-path",
+			Usage:       "the target volume path the volume is published to",
+			Destination: &volumePath,
+		},
+		cli.Uint64Flag{
+			Name:        "size",
+			Usage:       "the new size of the volume",
+			Destination: &size,
+		},
+	},
+	Action: func(c *cli.Context) error {
+		return volume.Resize(volumePath, size)
+	},
+}

src/runtime/cmd/kata-runtime/main.go

@@ -124,6 +124,7 @@ var runtimeCommands = []cli.Command{
 	kataExecCLICommand,
 	kataMetricsCLICommand,
 	factoryCLICommand,
+	kataVolumeCommand,
 }
 
 // runtimeBeforeSubcommands is the function to run before command-line