podman/libpod/diff.go
Daniel J Walsh 22c8270135
fix podman container exists and diff for storage containers
Current these commands only check if a container exists in libpod. With
this fix, the commands will also check if they are in containers/storage.

This allows users to look at differences within a buildah or CRI-O container.

Currently buildah diff does not exists, so this helps out in that situation
as well as in CRI-O since the cri does not implement a diff command.

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
2020-10-15 09:51:15 -04:00

84 lines
2 KiB
Go

package libpod
import (
"io"
"github.com/containers/podman/v2/libpod/layers"
"github.com/containers/storage/pkg/archive"
"github.com/pkg/errors"
)
var containerMounts = map[string]bool{
"/dev": true,
"/etc/hostname": true,
"/etc/hosts": true,
"/etc/resolv.conf": true,
"/proc": true,
"/run": true,
"/run/.containerenv": true,
"/run/secrets": true,
"/sys": true,
}
// GetDiff returns the differences between the two images, layers, or containers
func (r *Runtime) GetDiff(from, to string) ([]archive.Change, error) {
toLayer, err := r.getLayerID(to)
if err != nil {
return nil, err
}
fromLayer := ""
if from != "" {
fromLayer, err = r.getLayerID(from)
if err != nil {
return nil, err
}
}
var rchanges []archive.Change
changes, err := r.store.Changes(fromLayer, toLayer)
if err == nil {
for _, c := range changes {
if containerMounts[c.Path] {
continue
}
rchanges = append(rchanges, c)
}
}
return rchanges, err
}
// ApplyDiffTarStream applies the changes stored in 'diff' to the layer 'to'
func (r *Runtime) ApplyDiffTarStream(to string, diff io.Reader) error {
toLayer, err := r.getLayerID(to)
if err != nil {
return err
}
_, err = r.store.ApplyDiff(toLayer, diff)
return err
}
// GetLayerID gets a full layer id given a full or partial id
// If the id matches a container or image, the id of the top layer is returned
// If the id matches a layer, the top layer id is returned
func (r *Runtime) getLayerID(id string) (string, error) {
var toLayer string
toImage, err := r.imageRuntime.NewFromLocal(id)
if err == nil {
return toImage.TopLayer(), nil
}
targetID, err := r.store.Lookup(id)
if err != nil {
targetID = id
}
toCtr, err := r.store.Container(targetID)
if err != nil {
toLayer, err = layers.FullID(r.store, targetID)
if err != nil {
return "", errors.Errorf("layer, image, or container %s does not exist", id)
}
} else {
toLayer = toCtr.LayerID
}
return toLayer, nil
}