forked from willmtemple/os-explode
/
ref.go
75 lines (64 loc) · 2.23 KB
/
ref.go
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/* os-explode: automatically decompress docker images in OpenShift
* Copyright (C) 2016 Red Hat, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package watchclient
import (
"os"
"path"
log "github.com/Sirupsen/logrus"
imageapi "github.com/openshift/origin/pkg/image/api"
)
const digestLen = 71
// Produce a branch name (for OSTree, ostensibly) from an imagestream and its tag
func getFullRef(is *imageapi.ImageStream, tag string) string {
return path.Join(is.ObjectMeta.Namespace, is.ObjectMeta.Name, tag)
}
// Get the digest commited into a branch
func (wc *watchClient) digestForRef(imgref string) string {
file, err := os.OpenFile(path.Join(wc.OSTreeConfig.BasePath, "images", imgref, "link"), os.O_CREATE, 0744)
if err != nil {
log.WithField("img", imgref).Warn("No such reference")
return ""
}
defer file.Close()
var digest []byte
digest = make([]byte, digestLen)
if n, err := file.Read(digest); err != nil {
log.WithField("imgref", imgref).Error("Could not read ref")
return ""
} else if n != digestLen {
log.WithField("len", n).Debug("Digest read unexpected length")
}
return string(digest)
}
//Update an image reference to point to a new digest
func (wc *watchClient) updateRef(imgref, digest string) error {
//TODO: locking
lpath := path.Join(wc.OSTreeConfig.BasePath, "images", imgref, "link")
os.MkdirAll(path.Dir(lpath), 0755)
file, err := os.OpenFile(lpath, os.O_CREATE+os.O_RDWR, 0744)
if err != nil {
return err
}
defer file.Close()
if err := file.Truncate(0); err != nil {
return err
}
if _, err := file.Write([]byte(digest)); err != nil {
return err
}
return nil
}