129 lines
2.3 KiB
Go
129 lines
2.3 KiB
Go
package server
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import (
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"crypto/sha256"
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"errors"
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"fmt"
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"io"
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"os"
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)
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type Layer struct {
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MediaType string `json:"mediaType"`
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Digest string `json:"digest"`
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Size int64 `json:"size"`
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From string `json:"from,omitempty"`
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status string
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}
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func NewLayer(r io.Reader, mediatype string) (Layer, error) {
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blobs, err := GetBlobsPath("")
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if err != nil {
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return Layer{}, err
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}
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temp, err := os.CreateTemp(blobs, "sha256-")
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if err != nil {
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return Layer{}, err
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}
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defer temp.Close()
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defer os.Remove(temp.Name())
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sha256sum := sha256.New()
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n, err := io.Copy(io.MultiWriter(temp, sha256sum), r)
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if err != nil {
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return Layer{}, err
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}
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if err := temp.Close(); err != nil {
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return Layer{}, err
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}
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digest := fmt.Sprintf("sha256:%x", sha256sum.Sum(nil))
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blob, err := GetBlobsPath(digest)
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if err != nil {
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return Layer{}, err
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}
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status := "using existing layer"
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if _, err := os.Stat(blob); err != nil {
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status = "creating new layer"
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if err := os.Rename(temp.Name(), blob); err != nil {
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return Layer{}, err
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}
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if err := os.Chmod(blob, 0o644); err != nil {
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return Layer{}, err
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}
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}
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return Layer{
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MediaType: mediatype,
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Digest: digest,
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Size: n,
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status: fmt.Sprintf("%s %s", status, digest),
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}, nil
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}
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func NewLayerFromLayer(digest, mediatype, from string) (Layer, error) {
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if digest == "" {
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return Layer{}, errors.New("creating new layer from layer with empty digest")
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}
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blob, err := GetBlobsPath(digest)
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if err != nil {
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return Layer{}, err
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}
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fi, err := os.Stat(blob)
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if err != nil {
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return Layer{}, err
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}
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return Layer{
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MediaType: mediatype,
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Digest: digest,
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Size: fi.Size(),
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From: from,
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status: fmt.Sprintf("using existing layer %s", digest),
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}, nil
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}
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func (l *Layer) Open() (io.ReadSeekCloser, error) {
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if l.Digest == "" {
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return nil, errors.New("opening layer with empty digest")
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}
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blob, err := GetBlobsPath(l.Digest)
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if err != nil {
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return nil, err
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}
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return os.Open(blob)
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}
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func (l *Layer) Remove() error {
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if l.Digest == "" {
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return nil
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}
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ms, err := Manifests()
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if err != nil {
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return err
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}
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for _, m := range ms {
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for _, layer := range append(m.Layers, m.Config) {
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if layer.Digest == l.Digest {
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// something is using this layer
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return nil
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}
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}
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}
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blob, err := GetBlobsPath(l.Digest)
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if err != nil {
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return err
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}
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return os.Remove(blob)
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}
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