Merge pull request #722 from 14rcole/kpod-diff

Add kpod diff command

cmd/kpod/diff.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/containers/storage/pkg/archive"
+	"github.com/kubernetes-incubator/cri-o/libkpod"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+type diffJSONOutput struct {
+	Changed []string `json:"changed,omitempty"`
+	Added   []string `json:"added,omitempty"`
+	Deleted []string `json:"deleted,omitempty"`
+}
+
+var (
+	diffFlags = []cli.Flag{
+		cli.BoolFlag{
+			Name:   "archive",
+			Usage:  "Save the diff as a tar archive",
+			Hidden: true,
+		},
+		cli.BoolFlag{
+			Name:  "json",
+			Usage: "Format output as JSON",
+		},
+	}
+	diffDescription = fmt.Sprint(`Displays changes on a container or image's filesystem.  The
+	container or image will be compared to its parent layer`)
+
+	diffCommand = cli.Command{
+		Name:        "diff",
+		Usage:       "Inspect changes on container's file systems",
+		Description: diffDescription,
+		Flags:       diffFlags,
+		Action:      diffCmd,
+		ArgsUsage:   "ID-NAME",
+	}
+)
+
+func diffCmd(c *cli.Context) error {
+	if len(c.Args()) != 1 {
+		return errors.Errorf("container, layer, or image name must be specified: kpod diff [options [...]] ID-NAME")
+	}
+	config, err := getConfig(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get config")
+	}
+
+	server, err := libkpod.New(config)
+	if err != nil {
+		return errors.Wrapf(err, "could not get container server")
+	}
+
+	to := c.Args().Get(0)
+	changes, err := server.GetDiff("", to)
+	if err != nil {
+		return errors.Wrapf(err, "could not get changes for %q", to)
+	}
+
+	if c.Bool("json") {
+		jsonStruct := diffJSONOutput{}
+		for _, change := range changes {
+			if change.Kind == archive.ChangeModify {
+				jsonStruct.Changed = append(jsonStruct.Changed, change.Path)
+			} else if change.Kind == archive.ChangeAdd {
+				jsonStruct.Added = append(jsonStruct.Added, change.Path)
+			} else if change.Kind == archive.ChangeDelete {
+				jsonStruct.Deleted = append(jsonStruct.Deleted, change.Path)
+			} else {
+				return errors.Errorf("change kind %q not recognized", change.Kind.String())
+			}
+		}
+		b, err := json.MarshalIndent(jsonStruct, "", "  ")
+		if err != nil {
+			return errors.Wrapf(err, "could not marshal json for %+v", jsonStruct)
+		}
+		fmt.Println(string(b))
+	} else {
+		for _, change := range changes {
+			fmt.Println(change.String())
+		}
+	}
+
+	return nil
+}

cmd/kpod/main.go

@@ -22,6 +22,7 @@ func main() {
 	app.Version = Version
 
 	app.Commands = []cli.Command{
+		diffCommand,
 		exportCommand,
 		historyCommand,
 		imagesCommand,

docs/kpod-diff.1.md

@@ -0,0 +1,45 @@
+% kpod(1) kpod-diff - Inspect changes on a container or image's filesystem
+% Dan Walsh
+# kpod-diff "1" "August 2017" "kpod"
+
+## NAME
+kpod diff - Inspect changes on a container or image's filesystem
+
+## SYNOPSIS
+**kpod** **diff** [*options* [...]] NAME
+
+## DESCRIPTION
+Displays changes on a container or image's filesystem.  The container or image will be compared to its parent layer
+
+## OPTIONS
+
+**--json**
+
+Format output as json
+
+
+## EXAMPLE
+
+kpod diff redis:alpine
+C /usr
+C /usr/local
+C /usr/local/bin
+A /usr/local/bin/docker-entrypoint.sh
+
+kpod diff --json redis:alpine
+{
+  "changed": [
+    "/usr",
+    "/usr/local",
+    "/usr/local/bin"
+  ],
+  "added": [
+    "/usr/local/bin/docker-entrypoint.sh"
+  ]
+}
+
+## SEE ALSO
+kpod(1)
+
+## HISTORY
+August 2017, Originally compiled by Ryan Cole <rycole@redhat.com>

libkpod/diff.go

@@ -0,0 +1,54 @@
+package libkpod
+
+import (
+	"github.com/containers/storage/pkg/archive"
+	"github.com/kubernetes-incubator/cri-o/libkpod/image"
+	"github.com/kubernetes-incubator/cri-o/libkpod/layer"
+	"github.com/pkg/errors"
+)
+
+// GetDiff returns the differences betwen the two images, layers, or containers
+func (c *ContainerServer) GetDiff(from, to string) ([]archive.Change, error) {
+	toLayer, err := c.getLayerID(to)
+	if err != nil {
+		return nil, err
+	}
+	fromLayer := ""
+	if from != "" {
+		fromLayer, err = c.getLayerID(from)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return c.Store().Changes(fromLayer, toLayer)
+}
+
+// GetLayerID gets a full layer id given a full or partial id
+// If the id matches a container or image, the id of the top layer is returned
+// If the id matches a layer, the top layer id is returned
+func (c *ContainerServer) getLayerID(id string) (string, error) {
+	var toLayer string
+	toImage, err := image.FindImage(c.store, id)
+	if err != nil {
+		toCtr, err := c.store.Container(id)
+		if err != nil {
+			toLayer, err = layer.FullID(c.store, id)
+			if err != nil {
+				return "", errors.Errorf("layer, image, or container %s does not exist", id)
+			}
+		} else {
+			toLayer = toCtr.LayerID
+		}
+	} else {
+		toLayer = toImage.TopLayer
+	}
+	return toLayer, nil
+}
+
+func (c *ContainerServer) getLayerParent(layerID string) (string, error) {
+	layer, err := c.store.Layer(layerID)
+	if err != nil {
+		return "", err
+	}
+	return layer.Parent, nil
+}

libkpod/layer/layer.go

@@ -0,0 +1,12 @@
+package layer
+
+import cstorage "github.com/containers/storage"
+
+// FullID gets the full id of a layer given a partial id or name
+func FullID(store cstorage.Store, id string) (string, error) {
+	layer, err := store.Layer(id)
+	if err != nil {
+		return "", err
+	}
+	return layer.ID, nil
+}

test/kpod_diff.bats

@@ -0,0 +1,37 @@
+#/usr/bin/env bats
+
+load helpers
+
+IMAGE="alpine:latest"
+ROOT="$TESTDIR/crio"
+RUNROOT="$TESTDIR/crio-run"
+KPOD_OPTIONS="--root $ROOT --runroot $RUNROOT --storage-driver vfs"
+
+function teardown() {
+    cleanup_test
+}
+
+@test "test diff of image and parent" {
+    run ${KPOD_BINARY} $KPOD_OPTIONS pull $IMAGE
+    [ "$status" -eq 0 ]
+    run ${KPOD_BINARY} $KPOD_OPTIONS diff $IMAGE
+    [ "$status" -eq 0 ]
+    echo "$output"
+    run ${KKPOD_BINARY} $KPOD_OPTIONS rmi $IMAGE
+}
+
+@test "test diff on non-existent layer" {
+    run ${KPOD_BINARY} $KPOD_OPTIONS diff "abc123"
+    [ "$status" -ne 0 ]
+    echo "$output"
+}
+
+@test "test diff with json output" {
+    run ${KPOD_BINARY} $KPOD_OPTIONS pull $IMAGE
+    [ "$status" -eq 0 ]
+    # run bash -c "${KPOD_BINARY} ${KPOD_OPTIONS} diff --json $IMAGE | python -m json.tool"
+    run ${KPOD_BINARY} $KPOD_OPTIONS diff --json $IMAGE
+    [ "$status" -eq 0 ]
+    echo "$output"
+    run ${KKPOD_BINARY} $KPOD_OPTIONS rmi $IMAGE
+}