Tree implementation for podman images

Signed-off-by: Kunal Kushwaha <[email protected]>

cmd/podman/image.go

@@ -18,6 +18,7 @@ var (
 		rmImageCommand,
 		saveCommand,
 		tagCommand,
+		treeCommand,
 	}
 
 	imageDescription = "Manage images"

cmd/podman/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log/syslog"
 	"os"
 	"os/exec"
 	"runtime/pprof"
@@ -17,7 +18,6 @@ import (
 	"github.com/sirupsen/logrus"
 	lsyslog "github.com/sirupsen/logrus/hooks/syslog"
 	"github.com/urfave/cli"
-	"log/syslog"
 )
 
 // This is populated by the Makefile from the VERSION file

cmd/podman/tree.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containers/libpod/cmd/podman/libpodruntime"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	treeDescription = "Displays the dependent layers of an image. The information is printed in tree format"
+
+	treeCommand = cli.Command{
+		Name:                   "tree",
+		Usage:                  "Show dependent layers of a specified image in tree format",
+		Description:            treeDescription,
+		Action:                 treeCmd,
+		ArgsUsage:              "",
+		UseShortOptionHandling: true,
+	}
+)
+
+func treeCmd(c *cli.Context) error {
+
+	runtime, err := libpodruntime.GetRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get runtime")
+	}
+	defer runtime.Shutdown(false)
+
+	args := c.Args()
+	if len(args) == 0 {
+		return errors.Errorf("an image name must be specified")
+	}
+	if len(args) > 1 {
+		return errors.Errorf("podman tree takes at most 1 argument")
+	}
+
+	image, err := runtime.ImageRuntime().NewFromLocal(args[0])
+	if err != nil {
+		return err
+	}
+
+	out, err := image.Tree(context.Background())
+	if err != nil {
+		return errors.Wrapf(err, "error getting dependencies of image %q", image.InputName)
+	}
+	fmt.Println(out)
+
+	return nil
+}

docs/podman-image.1.md

@@ -24,6 +24,7 @@ The image command allows you to manage images
 | rm       | [podman-rm(1)](podman-rmi.1.md)           | Removes one or more locally stored images.                                     |
 | save     | [podman-save(1)](podman-save.1.md)        | Save an image to docker-archive or oci.                                        |
 | tag      | [podman-tag(1)](podman-tag.1.md)          | Add an additional name to a local image.                                       |
+| tree     | [podman-tree(1)](podman-tree.1.md)        | Show dependent layers of a specified image in tree format                      |
 
 ## SEE ALSO
 podman

docs/podman-tree.1.md

@@ -0,0 +1,33 @@
+% podman-tree "1"
+
+## NAME
+podman\-tree - Show dependent layers of a specified image in tree format
+
+## SYNOPSIS
+**podman tree** [*image*:*tag*]**|**[*image-id*]
+[**--help**|**-h**]
+
+## DESCRIPTION
+Displays the dependent layers of an image. The information is printed in tree format.
+If you do not provide *tag*, podman will default to `latest` for the *image*.
+
+## OPTIONS
+
+**--help**, **-h**
+
+Print usage statement
+
+## EXAMPLES
+
+```
+$ podman tree fedora:latest
+
+$ podman tree 243d869d10ea
+```
+
+
+## SEE ALSO
+podman(1), crio(8)
+
+## HISTORY
+Oct 2018, Originally compiled by Kunal Kushwaha <[email protected]>

libpod/image/image.go

@@ -1,6 +1,7 @@
 package image
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -25,6 +26,7 @@ import (
 	"github.com/containers/libpod/pkg/util"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/reexec"
+	"github.com/docker/go-units"
 	"github.com/opencontainers/go-digest"
 	ociv1 "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
@@ -1075,3 +1077,62 @@ func (i *Image) Comment(ctx context.Context, manifestType string) (string, error
 	}
 	return ociv1Img.History[0].Comment, nil
 }
+
+// Tree gets dependencies of image
+func (i *Image) Tree(ctx context.Context) (*bytes.Buffer, error) {
+	treeDepth := 1
+	rootImage := i
+
+	//Traverse to the root(base) image
+	parent, err := i.GetParent()
+	if err != nil {
+		return nil, err
+	}
+
+	for parent != nil {
+		rootImage = parent
+		parent, err = parent.GetParent()
+		if err != nil {
+			break
+		}
+		treeDepth++
+	}
+
+	var buffer bytes.Buffer
+	//Print all subtree(peers) to the depth of input image
+	err = printSubTree(&buffer, rootImage, 0, "└─ ", treeDepth)
+
+	return &buffer, err
+}
+
+func printSubTree(buffer *bytes.Buffer, root *Image, rootSize uint64, prefix string, treeDepth int) error {
+	if treeDepth == 0 {
+		return nil
+	}
+	size, err := root.Size(context.Background())
+	if err != nil {
+		return err
+	}
+	//Size of current layer will be current layer size minus upper layer
+	buffer.WriteString(fmt.Sprintf("%s ID: %s  Tags: %v VirtualSize: %s\n",
+		prefix,
+		root.ID()[:12],
+		root.Names(),
+		units.HumanSizeWithPrecision(float64(*size-rootSize), 4)),
+	)
+
+	children, err := root.GetChildren()
+	if err != nil {
+		return nil
+	}
+
+	for _, child := range children {
+		img, err := root.imageruntime.getImage(child)
+		if err != nil {
+			break
+		}
+		nextPrefix := "  "
+		printSubTree(buffer, img, *size, nextPrefix+prefix, treeDepth-1)
+	}
+	return nil
+}