Podman history now prints out intermediate image IDs

If the intermediate image exists in the store, podman history
will show the IDs of the intermediate image of each layer.

Signed-off-by: umohnani8 <umohnani@redhat.com>

Closes: #982
Approved by: mheon

3 files changed, 101 insertions, 84 deletions

diff --git a/cmd/podman/history.go b/cmd/podman/history.go
index 4f3867d34..2570dcc7d 100644
--- a/cmd/podman/history.go
+++ b/cmd/podman/history.go
@@ -6,12 +6,11 @@ import (
 	"strings"
 	"time"
 
-	"github.com/containers/image/types"
 	units "github.com/docker/go-units"
-	"github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"github.com/projectatomic/libpod/cmd/podman/formats"
 	"github.com/projectatomic/libpod/cmd/podman/libpodruntime"
+	"github.com/projectatomic/libpod/libpod/image"
 	"github.com/urfave/cli"
 )
 
@@ -26,18 +25,6 @@ type historyTemplateParams struct {
 	Comment   string
 }
 
-// historyJSONParams is only used when the JSON format is specified,
-// and is better for data processing from JSON.
-// historyJSONParams will be populated by data from v1.History and types.BlobInfo,
-// the members of the struct are the sama data types as their sources.
-type historyJSONParams struct {
-	ID        string     `json:"id"`
-	Created   *time.Time `json:"created"`
-	CreatedBy string     `json:"createdBy"`
-	Size      int64      `json:"size"`
-	Comment   string     `json:"comment"`
-}
-
 // historyOptions stores cli flag values
 type historyOptions struct {
 	human   bool
@@ -111,12 +98,12 @@ func historyCmd(c *cli.Context) error {
 		format:  format,
 	}
 
-	history, layers, err := image.History(getContext())
+	history, err := image.History(getContext())
 	if err != nil {
 		return errors.Wrapf(err, "error getting history of image %q", image.InputName)
 	}
 
-	return generateHistoryOutput(history, layers, image.ID(), opts)
+	return generateHistoryOutput(history, opts)
 }
 
 func genHistoryFormat(format string, quiet bool) string {
@@ -132,7 +119,7 @@ func genHistoryFormat(format string, quiet bool) string {
 }
 
 // historyToGeneric makes an empty array of interfaces for output
-func historyToGeneric(templParams []historyTemplateParams, JSONParams []historyJSONParams) (genericParams []interface{}) {
+func historyToGeneric(templParams []historyTemplateParams, JSONParams []*image.History) (genericParams []interface{}) {
 	if len(templParams) > 0 {
 		for _, v := range templParams {
 			genericParams = append(genericParams, interface{}(v))
@@ -158,36 +145,27 @@ func (h *historyTemplateParams) headerMap() map[string]string {
 }
 
 // getHistorytemplateOutput gets the modified history information to be printed in human readable format
-func getHistoryTemplateOutput(history []v1.History, layers []types.BlobInfo, imageID string, opts historyOptions) (historyOutput []historyTemplateParams) {
+func getHistoryTemplateOutput(history []*image.History, opts historyOptions) (historyOutput []historyTemplateParams) {
 	var (
 		outputSize  string
 		createdTime string
 		createdBy   string
-		count       = 1
 	)
-	for i := len(history) - 1; i >= 0; i-- {
-		if i != len(history)-1 {
-			imageID = "<missing>"
-		}
-		if !opts.noTrunc && i == len(history)-1 {
+	for _, hist := range history {
+		imageID := hist.ID
+		if !opts.noTrunc && imageID != "<missing>" {
 			imageID = shortID(imageID)
 		}
 
-		var size int64
-		if !history[i].EmptyLayer {
-			size = layers[len(layers)-count].Size
-			count++
-		}
-
 		if opts.human {
-			createdTime = units.HumanDuration(time.Since((*history[i].Created))) + " ago"
-			outputSize = units.HumanSize(float64(size))
+			createdTime = units.HumanDuration(time.Since((*hist.Created))) + " ago"
+			outputSize = units.HumanSize(float64(hist.Size))
 		} else {
-			createdTime = (history[i].Created).Format(time.RFC3339)
-			outputSize = strconv.FormatInt(size, 10)
+			createdTime = (hist.Created).Format(time.RFC3339)
+			outputSize = strconv.FormatInt(hist.Size, 10)
 		}
 
-		createdBy = strings.Join(strings.Fields(history[i].CreatedBy), " ")
+		createdBy = strings.Join(strings.Fields(hist.CreatedBy), " ")
 		if !opts.noTrunc && len(createdBy) > createdByTruncLength {
 			createdBy = createdBy[:createdByTruncLength-3] + "..."
 		}
@@ -197,29 +175,7 @@ func getHistoryTemplateOutput(history []v1.History, layers []types.BlobInfo, ima
 			Created:   createdTime,
 			CreatedBy: createdBy,
 			Size:      outputSize,
-			Comment:   history[i].Comment,
-		}
-		historyOutput = append(historyOutput, params)
-	}
-	return
-}
-
-// getHistoryJSONOutput returns the history information in its raw form
-func getHistoryJSONOutput(history []v1.History, layers []types.BlobInfo, imageID string) (historyOutput []historyJSONParams) {
-	count := 1
-	for i := len(history) - 1; i >= 0; i-- {
-		var size int64
-		if !history[i].EmptyLayer {
-			size = layers[len(layers)-count].Size
-			count++
-		}
-
-		params := historyJSONParams{
-			ID:        imageID,
-			Created:   history[i].Created,
-			CreatedBy: history[i].CreatedBy,
-			Size:      size,
-			Comment:   history[i].Comment,
+			Comment:   hist.Comment,
 		}
 		historyOutput = append(historyOutput, params)
 	}
@@ -227,7 +183,7 @@ func getHistoryJSONOutput(history []v1.History, layers []types.BlobInfo, imageID
 }
 
 // generateHistoryOutput generates the history based on the format given
-func generateHistoryOutput(history []v1.History, layers []types.BlobInfo, imageID string, opts historyOptions) error {
+func generateHistoryOutput(history []*image.History, opts historyOptions) error {
 	if len(history) == 0 {
 		return nil
 	}
@@ -236,11 +192,10 @@ func generateHistoryOutput(history []v1.History, layers []types.BlobInfo, imageI
 
 	switch opts.format {
 	case formats.JSONString:
-		historyOutput := getHistoryJSONOutput(history, layers, imageID)
-		out = formats.JSONStructArray{Output: historyToGeneric([]historyTemplateParams{}, historyOutput)}
+		out = formats.JSONStructArray{Output: historyToGeneric([]historyTemplateParams{}, history)}
 	default:
-		historyOutput := getHistoryTemplateOutput(history, layers, imageID, opts)
-		out = formats.StdoutTemplateArray{Output: historyToGeneric(historyOutput, []historyJSONParams{}), Template: opts.format, Fields: historyOutput[0].headerMap()}
+		historyOutput := getHistoryTemplateOutput(history, opts)
+		out = formats.StdoutTemplateArray{Output: historyToGeneric(historyOutput, []*image.History{}), Template: opts.format, Fields: historyOutput[0].headerMap()}
 	}
 
 	return formats.Writer(out).Out()
diff --git a/libpod/image/image.go b/libpod/image/image.go
index c8a929074..57eabe2c8 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -608,17 +608,87 @@ func (i *Image) Layer() (*storage.Layer, error) {
 	return i.imageruntime.store.Layer(i.image.TopLayer)
 }
 
+// History contains the history information of an image
+type History struct {
+	ID        string     `json:"id"`
+	Created   *time.Time `json:"created"`
+	CreatedBy string     `json:"createdBy"`
+	Size      int64      `json:"size"`
+	Comment   string     `json:"comment"`
+}
+
 // History gets the history of an image and information about its layers
-func (i *Image) History(ctx context.Context) ([]ociv1.History, []types.BlobInfo, error) {
+func (i *Image) History(ctx context.Context) ([]*History, error) {
 	img, err := i.toImageRef(ctx)
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 	oci, err := img.OCIConfig(ctx)
 	if err != nil {
-		return nil, nil, err
+		return nil, err
+	}
+
+	// Get the IDs of the images making up the history layers
+	// if the images exist locally in the store
+	images, err := i.imageruntime.GetImages()
+	if err != nil {
+		return nil, errors.Wrapf(err, "error getting images from store")
+	}
+	imageIDs := []string{i.ID()}
+	if err := i.historyLayerIDs(i.TopLayer(), images, &imageIDs); err != nil {
+		return nil, errors.Wrap(err, "error getting image IDs for layers in history")
 	}
-	return oci.History, img.LayerInfos(), nil
+
+	var (
+		imageID    string
+		imgIDCount = 0
+		size       int64
+		sizeCount  = 1
+		allHistory []*History
+	)
+
+	for i := len(oci.History) - 1; i >= 0; i-- {
+		if imgIDCount < len(imageIDs) {
+			imageID = imageIDs[imgIDCount]
+			imgIDCount++
+		} else {
+			imageID = "<missing>"
+		}
+		if !oci.History[i].EmptyLayer {
+			size = img.LayerInfos()[len(img.LayerInfos())-sizeCount].Size
+			sizeCount++
+		}
+		allHistory = append(allHistory, &History{
+			ID:        imageID,
+			Created:   oci.History[i].Created,
+			CreatedBy: oci.History[i].CreatedBy,
+			Size:      size,
+			Comment:   oci.History[i].Comment,
+		})
+	}
+
+	return allHistory, nil
+}
+
+// historyLayerIDs goes through the images in store and checks if the top layer of an image
+// is the same as the parent of topLayerID
+func (i *Image) historyLayerIDs(topLayerID string, images []*Image, IDs *[]string) error {
+	for _, image := range images {
+		// Get the layer info of topLayerID
+		layer, err := i.imageruntime.store.Layer(topLayerID)
+		if err != nil {
+			return errors.Wrapf(err, "error getting layer info %q", topLayerID)
+		}
+		// Check if the parent of layer is equal to the image's top layer
+		// If so add the image ID to the list of IDs and find the parent of
+		// the top layer of the image ID added to the list
+		// Since we are checking for parent, each top layer can only have one parent
+		if layer.Parent == image.TopLayer() {
+			*IDs = append(*IDs, image.ID())
+			return i.historyLayerIDs(image.TopLayer(), images, IDs)
+		}
+	}
+	return nil
 }
 
 // Dangling returns a bool if the image is "dangling"
diff --git a/pkg/varlinkapi/images.go b/pkg/varlinkapi/images.go
index 420962973..8e2669660 100644
--- a/pkg/varlinkapi/images.go
+++ b/pkg/varlinkapi/images.go
@@ -1,6 +1,7 @@
 package varlinkapi
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -8,7 +9,6 @@ import (
 	"strings"
 	"time"
 
-	"bytes"
 	"github.com/containers/image/docker"
 	"github.com/containers/image/types"
 	"github.com/docker/go-units"
@@ -307,27 +307,19 @@ func (i *LibpodAPI) HistoryImage(call ioprojectatomicpodman.VarlinkCall, name st
 	if err != nil {
 		return call.ReplyImageNotFound(name)
 	}
-	history, layerInfos, err := newImage.History(getContext())
+	history, err := newImage.History(getContext())
 	if err != nil {
 		return call.ReplyErrorOccurred(err.Error())
 	}
-	var (
-		histories []ioprojectatomicpodman.ImageHistory
-		count     = 1
-	)
-	for i := len(history) - 1; i >= 0; i-- {
-		var size int64
-		if !history[i].EmptyLayer {
-			size = layerInfos[len(layerInfos)-count].Size
-			count++
-		}
+	var histories []ioprojectatomicpodman.ImageHistory
+	for _, hist := range history {
 		imageHistory := ioprojectatomicpodman.ImageHistory{
-			Id:        newImage.ID(),
-			Created:   history[i].Created.String(),
-			CreatedBy: history[i].CreatedBy,
+			Id:        hist.ID,
+			Created:   hist.Created.String(),
+			CreatedBy: hist.CreatedBy,
 			Tags:      newImage.Names(),
-			Size:      size,
-			Comment:   history[i].Comment,
+			Size:      hist.Size,
+			Comment:   hist.Comment,
 		}
 		histories = append(histories, imageHistory)
 	}