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Only scan the tar file once (#103)

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This commit is contained in:
Chris Cinelli 2018-11-29 14:46:32 -08:00 committed by Alex Goodman
parent 530ea555cb
commit 3edff1760d
1 changed files with 18 additions and 55 deletions
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73
image/image.go
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@ -97,30 +97,18 @@ type ImageHistoryEntry struct {
EmptyLayer bool `json:"empty_layer"`
}
func NewImageManifest(reader *tar.Reader, header *tar.Header) ImageManifest {
size := header.Size
manifestBytes := make([]byte, size)
_, err := reader.Read(manifestBytes)
if err != nil && err != io.EOF {
logrus.Panic(err)
}
func NewImageManifest(manifestBytes []byte) ImageManifest {
var manifest []ImageManifest
err = json.Unmarshal(manifestBytes, &manifest)
err := json.Unmarshal(manifestBytes, &manifest)
if err != nil {
logrus.Panic(err)
}
return manifest[0]
}
func NewImageConfig(reader *tar.Reader, header *tar.Header) ImageConfig {
size := header.Size
configBytes := make([]byte, size)
_, err := reader.Read(configBytes)
if err != nil && err != io.EOF {
logrus.Panic(err)
}
func NewImageConfig(configBytes []byte) ImageConfig {
var imageConfig ImageConfig
err = json.Unmarshal(configBytes, &imageConfig)
err := json.Unmarshal(configBytes, &imageConfig)
if err != nil {
logrus.Panic(err)
}
@ -138,40 +126,6 @@ func NewImageConfig(reader *tar.Reader, header *tar.Header) ImageConfig {
return imageConfig
}
func GetImageConfig(imageTarPath string, manifest ImageManifest) ImageConfig {
var config ImageConfig
// read through the image contents and build a tree
fmt.Println(" Fetching image config...")
tarFile, err := os.Open(imageTarPath)
if err != nil {
fmt.Println(err)
utils.Exit(1)
}
defer tarFile.Close()
tarReader := tar.NewReader(tarFile)
for {
header, err := tarReader.Next()
if err == io.EOF {
break
}
if err != nil {
fmt.Println(err)
utils.Exit(1)
}
name := header.Name
if name == manifest.ConfigPath {
config = NewImageConfig(tarReader, header)
}
}
// obtain the image history
return config
}
func processLayerTar(line *jotframe.Line, layerMap map[string]*filetree.FileTree, name string, tarredBytes []byte) {
tree := filetree.NewFileTree()
tree.Name = name
@ -196,7 +150,6 @@ func processLayerTar(line *jotframe.Line, layerMap map[string]*filetree.FileTree
}
func InitializeData(imageID string) ([]*Layer, []*filetree.FileTree, float64, filetree.EfficiencySlice) {
var manifest ImageManifest
var layerMap = make(map[string]*filetree.FileTree)
var trees = make([]*filetree.FileTree, 0)
@ -240,6 +193,10 @@ func InitializeData(imageID string) ([]*Layer, []*filetree.FileTree, float64, fi
tarReader := tar.NewReader(tarFile)
frame := jotframe.NewFixedFrame(1, true, false, false)
lastLine := frame.Lines()[0]
// json files are small. Let's store the in a map so we can read the image in one pass
jsonFiles := make(map[string][]byte)
io.WriteString(lastLine, " ╧")
lastLine.Close()
@ -261,6 +218,7 @@ func InitializeData(imageID string) ([]*Layer, []*filetree.FileTree, float64, fi
io.WriteString(frame.Header(), fmt.Sprintf(" Discovering layers... %d %%", percent))
name := header.Name
var n int
// some layer tars can be relative layer symlinks to other layer tars
if header.Typeflag == tar.TypeSymlink || header.Typeflag == tar.TypeReg {
@ -281,8 +239,13 @@ func InitializeData(imageID string) ([]*Layer, []*filetree.FileTree, float64, fi
}
go processLayerTar(line, layerMap, name, tarredBytes)
} else if name == "manifest.json" {
manifest = NewImageManifest(tarReader, header)
} else if strings.HasSuffix(name, ".json") {
var fileBuffer = make([]byte, header.Size)
n, err = tarReader.Read(fileBuffer)
if err != nil && err != io.EOF && int64(n) != header.Size {
logrus.Panic(err)
}
jsonFiles[name] = fileBuffer
}
}
}
@ -291,8 +254,8 @@ func InitializeData(imageID string) ([]*Layer, []*filetree.FileTree, float64, fi
frame.Remove(lastLine)
fmt.Println("")
// obtain the image history
config := GetImageConfig(imageTarPath, manifest)
manifest := NewImageManifest(jsonFiles["manifest.json"])
config := NewImageConfig(jsonFiles[manifest.ConfigPath])
// build the content tree
fmt.Println(" Building tree...")