Add kpod-mount and kpod-umount to mount and umount container images

This command will allow users to manipulate and examine the container
images from outside of the container.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

cmd/kpod/mount.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	js "encoding/json"
+	"fmt"
+
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	mountDescription = `
+   kpod mount
+   Lists all mounted containers mount points
+
+   kpod mount CONTAINER-NAME-OR-ID
+   Mounts the specified container and outputs the mountpoint
+`
+
+	mountFlags = []cli.Flag{
+		cli.BoolFlag{
+			Name:  "notruncate",
+			Usage: "do not truncate output",
+		},
+		cli.StringFlag{
+			Name:  "label",
+			Usage: "SELinux label for the mount point",
+		},
+		cli.StringFlag{
+			Name:  "format",
+			Usage: "Print mounted containers in specified format",
+		},
+	}
+	mountCommand = cli.Command{
+		Name:        "mount",
+		Usage:       "Mount a working container's root filesystem",
+		Description: mountDescription,
+		Action:      mountCmd,
+		ArgsUsage:   "[CONTAINER-NAME-OR-ID]",
+		Flags:       mountFlags,
+	}
+)
+
+// MountOutputParams stores info about each layer
+type jsonMountPoint struct {
+	ID         string   `json:"id"`
+	Names      []string `json:"names"`
+	MountPoint string   `json:"mountpoint"`
+}
+
+func mountCmd(c *cli.Context) error {
+	formats := map[string]bool{
+		"":     true,
+		"json": true,
+	}
+
+	args := c.Args()
+	json := c.String("format") == "json"
+	if !formats[c.String("format")] {
+		return errors.Errorf("%q is not a supported format", c.String("format"))
+	}
+
+	if len(args) > 1 {
+		return errors.Errorf("too many arguments specified")
+	}
+	config, err := getConfig(c)
+	if err != nil {
+		return errors.Wrapf(err, "Could not get config")
+	}
+	store, err := getStore(config)
+	if err != nil {
+		return errors.Wrapf(err, "error getting store")
+	}
+	if len(args) == 1 {
+		if json {
+			return errors.Wrapf(err, "json option can not be used with a container id")
+		}
+		mountPoint, err := store.Mount(args[0], c.String("label"))
+		if err != nil {
+			return errors.Wrapf(err, "error finding container %q", args[0])
+		}
+		fmt.Printf("%s\n", mountPoint)
+	} else {
+		jsonMountPoints := []jsonMountPoint{}
+		containers, err2 := store.Containers()
+		if err2 != nil {
+			return errors.Wrapf(err2, "error reading list of all containers")
+		}
+		for _, container := range containers {
+			layer, err := store.Layer(container.LayerID)
+			if err != nil {
+				return errors.Wrapf(err, "error finding layer %q for container %q", container.LayerID, container.ID)
+			}
+			if layer.MountPoint == "" {
+				continue
+			}
+			if json {
+				jsonMountPoints = append(jsonMountPoints, jsonMountPoint{ID: container.ID, Names: container.Names, MountPoint: layer.MountPoint})
+				continue
+			}
+
+			if c.Bool("notruncate") {
+				fmt.Printf("%-64s %s\n", container.ID, layer.MountPoint)
+			} else {
+				fmt.Printf("%-12.12s %s\n", container.ID, layer.MountPoint)
+			}
+		}
+		if json {
+			data, err := js.MarshalIndent(jsonMountPoints, "", "    ")
+			if err != nil {
+				return err
+			}
+			fmt.Printf("%s\n", data)
+		}
+	}
+	return nil
+}