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package main
import (
"context"
"fmt"
"github.com/containers/libpod/cmd/podman/cliconfig"
"github.com/containers/libpod/cmd/podman/libpodruntime"
"github.com/containers/libpod/libpod/image"
units "github.com/docker/go-units"
"github.com/pkg/errors"
"github.com/spf13/cobra"
)
const (
middleItem = "├── "
continueItem = "│ "
lastItem = "└── "
)
var (
treeCommand cliconfig.TreeValues
treeDescription = "Prints layer hierarchy of an image in a tree format"
_treeCommand = &cobra.Command{
Use: "tree",
Short: treeDescription,
Long: treeDescription,
RunE: func(cmd *cobra.Command, args []string) error {
treeCommand.InputArgs = args
treeCommand.GlobalFlags = MainGlobalOpts
return treeCmd(&treeCommand)
},
Example: "podman image tree alpine:latest",
}
)
func init() {
treeCommand.Command = _treeCommand
treeCommand.SetUsageTemplate(UsageTemplate())
treeCommand.Flags().BoolVar(&treeCommand.WhatRequires, "whatrequires", false, "Show all child images and layers of the specified image")
}
// infoImage keep information of Image along with all associated layers
type infoImage struct {
// id of image
id string
// tags of image
tags []string
// layers stores all layers of image.
layers []image.LayerInfo
}
func treeCmd(c *cliconfig.TreeValues) error {
args := c.InputArgs
if len(args) == 0 {
return errors.Errorf("an image name must be specified")
}
if len(args) > 1 {
return errors.Errorf("you must provide at most 1 argument")
}
runtime, err := libpodruntime.GetRuntime(&c.PodmanCommand)
if err != nil {
return errors.Wrapf(err, "error creating libpod runtime")
}
defer runtime.Shutdown(false)
img, err := runtime.ImageRuntime().NewFromLocal(args[0])
if err != nil {
return err
}
// Fetch map of image-layers, which is used for printing output.
layerInfoMap, err := image.GetLayersMapWithImageInfo(runtime.ImageRuntime())
if err != nil {
return errors.Wrapf(err, "error while retriving layers of image %q", img.InputName)
}
// Create an imageInfo and fill the image and layer info
imageInfo := &infoImage{
id: img.ID(),
tags: img.Names(),
}
size, err := img.Size(context.Background())
if err != nil {
return errors.Wrapf(err, "error while retriving image size")
}
fmt.Printf("Image ID: %s\n", imageInfo.id[:12])
fmt.Printf("Tags:\t %s\n", imageInfo.tags)
fmt.Printf("Size:\t %v\n", units.HumanSizeWithPrecision(float64(*size), 4))
fmt.Printf(fmt.Sprintf("Image Layers\n"))
if !c.WhatRequires {
// fill imageInfo with layers associated with image.
// the layers will be filled such that
// (Start)RootLayer->...intermediate Parent Layer(s)-> TopLayer(End)
err := buildImageHierarchyMap(imageInfo, layerInfoMap, img.TopLayer())
if err != nil {
return err
}
// Build output from imageInfo into buffer
printImageHierarchy(imageInfo)
} else {
// fill imageInfo with layers associated with image.
// the layers will be filled such that
// (Start)TopLayer->...intermediate Child Layer(s)-> Child TopLayer(End)
// (Forks)... intermediate Child Layer(s) -> Child Top Layer(End)
err := printImageChildren(layerInfoMap, img.TopLayer(), "", true)
if err != nil {
return err
}
}
return nil
}
// Stores hierarchy of images such that all parent layers using which image is built are stored in imageInfo
// Layers are added such that (Start)RootLayer->...intermediate Parent Layer(s)-> TopLayer(End)
func buildImageHierarchyMap(imageInfo *infoImage, layerMap map[string]*image.LayerInfo, layerID string) error {
if layerID == "" {
return nil
}
ll, ok := layerMap[layerID]
if !ok {
return fmt.Errorf("lookup error: layerid %s not found", layerID)
}
if err := buildImageHierarchyMap(imageInfo, layerMap, ll.ParentID); err != nil {
return err
}
imageInfo.layers = append(imageInfo.layers, *ll)
return nil
}
// Stores all children layers which are created using given Image.
// Layers are stored as follows
// (Start)TopLayer->...intermediate Child Layer(s)-> Child TopLayer(End)
// (Forks)... intermediate Child Layer(s) -> Child Top Layer(End)
func printImageChildren(layerMap map[string]*image.LayerInfo, layerID string, prefix string, last bool) error {
if layerID == "" {
return nil
}
ll, ok := layerMap[layerID]
if !ok {
return fmt.Errorf("lookup error: layerid %s, not found", layerID)
}
fmt.Printf(prefix)
//initialize intend with middleItem to reduce middleItem checks.
intend := middleItem
if !last {
// add continueItem i.e. '|' for next iteration prefix
prefix = prefix + continueItem
} else if len(ll.ChildID) > 1 || len(ll.ChildID) == 0 {
// The above condition ensure, alignment happens for node, which has more then 1 childern.
// If node is last in printing hierarchy, it should not be printed as middleItem i.e. ├──
intend = lastItem
prefix = prefix + " "
}
var tags string
if len(ll.RepoTags) > 0 {
tags = fmt.Sprintf(" Top Layer of: %s", ll.RepoTags)
}
fmt.Printf("%sID: %s Size: %7v%s\n", intend, ll.ID[:12], units.HumanSizeWithPrecision(float64(ll.Size), 4), tags)
for count, childID := range ll.ChildID {
if err := printImageChildren(layerMap, childID, prefix, (count == len(ll.ChildID)-1)); err != nil {
return err
}
}
return nil
}
// prints the layers info of image
func printImageHierarchy(imageInfo *infoImage) {
for count, l := range imageInfo.layers {
var tags string
intend := middleItem
if len(l.RepoTags) > 0 {
tags = fmt.Sprintf(" Top Layer of: %s", l.RepoTags)
}
if count == len(imageInfo.layers)-1 {
intend = lastItem
}
fmt.Printf("%s ID: %s Size: %7v%s\n", intend, l.ID[:12], units.HumanSizeWithPrecision(float64(l.Size), 4), tags)
}
}
|