Update naive driver to use storage package

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
This commit is contained in:
Derek McGowan 2017-04-05 13:56:27 -07:00
parent cccf5d3723
commit 8a73673b5b
No known key found for this signature in database
GPG key ID: F58C5D0A4405ACDB
2 changed files with 234 additions and 156 deletions

View file

@ -1,117 +1,263 @@
package naive package naive
import ( import (
"fmt" "context"
"io/ioutil" "io/ioutil"
"os" "os"
"path/filepath" "path/filepath"
"github.com/containerd/containerd" "github.com/containerd/containerd"
"github.com/containerd/containerd/fs" "github.com/containerd/containerd/fs"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/plugin"
"github.com/containerd/containerd/snapshot"
"github.com/containerd/containerd/snapshot/storage"
"github.com/pkg/errors" "github.com/pkg/errors"
) )
type Naive struct { func init() {
plugin.Register("snapshot-naive", &plugin.Registration{
Type: plugin.SnapshotPlugin,
Init: func(ic *plugin.InitContext) (interface{}, error) {
return NewSnapshotter(filepath.Join(ic.Root, "snapshot", "naive"))
},
})
}
type snapshotter struct {
root string root string
ms *storage.MetaStore
// TODO(stevvooe): Very lazy copying from the overlay driver. We'll have to
// put *all* of this on disk in an easy to access format.
active map[string]activeNaiveSnapshot
parents map[string]string // mirror of what is on disk
} }
type activeNaiveSnapshot struct { // NewSnapshotter returns a Snapshotter which copies layers on the underlying
parent string // file system. A metadata file is stored under the root.
metadata string func NewSnapshotter(root string) (snapshot.Snapshotter, error) {
} if err := os.MkdirAll(root, 0700); err != nil {
return nil, err
func NewNaive(root string) (*Naive, error) { }
if err := os.MkdirAll(root, 0777); err != nil { ms, err := storage.NewMetaStore(filepath.Join(root, "metadata.db"))
if err != nil {
return nil, err return nil, err
} }
// TODO(stevvooe): Recover active transactions. if err := os.Mkdir(filepath.Join(root, "snapshots"), 0700); err != nil {
return nil, err
}
return &Naive{ return &snapshotter{
root: root, root: root,
active: make(map[string]activeNaiveSnapshot), ms: ms,
parents: make(map[string]string),
}, nil }, nil
} }
// Prepare works per the snapshot specification. // Stat returns the info for an active or committed snapshot by name or
// key.
// //
// For the naive driver, the data is checked out directly into dst and no // Should be used for parent resolution, existence checks and to discern
// mounts are returned. // the kind of snapshot.
func (n *Naive) Prepare(dst, parent string) ([]containerd.Mount, error) { func (o *snapshotter) Stat(ctx context.Context, key string) (snapshot.Info, error) {
metadataRoot, err := ioutil.TempDir(n.root, "active-") ctx, t, err := o.ms.TransactionContext(ctx, false)
if err != nil { if err != nil {
return nil, errors.Wrap(err, "failed to created transaction dir") return snapshot.Info{}, err
} }
defer t.Rollback()
// TODO(stevvooe): Write in driver metadata so it can be identified, return storage.GetInfo(ctx, key)
// probably part of common manager type.
if err := ioutil.WriteFile(filepath.Join(metadataRoot, "target"), []byte(dst), 0777); err != nil {
return nil, errors.Wrap(err, "failed to write target to disk")
}
if parent != "" {
if _, ok := n.parents[parent]; !ok {
return nil, errors.Wrap(err, "specified parent does not exist")
}
if err := ioutil.WriteFile(filepath.Join(metadataRoot, "parent"), []byte(parent), 0777); err != nil {
return nil, errors.Wrap(err, "error specifying parent")
}
// Now, we copy the parent filesystem, just a directory, into dst.
if err := fs.CopyDir(dst, filepath.Join(parent, "data")); err != nil {
return nil, errors.Wrap(err, "copying of parent failed")
}
}
n.active[dst] = activeNaiveSnapshot{
parent: parent,
metadata: metadataRoot,
}
return nil, nil // no mounts!!
} }
// Commit just moves the metadata directory to the diff location. func (o *snapshotter) Prepare(ctx context.Context, key, parent string) ([]containerd.Mount, error) {
func (n *Naive) Commit(diff, dst string) error { return o.createActive(ctx, key, parent, false)
active, ok := n.active[dst] }
if !ok {
return errors.Errorf("%v is not an active transaction", dst) func (o *snapshotter) View(ctx context.Context, key, parent string) ([]containerd.Mount, error) {
return o.createActive(ctx, key, parent, true)
}
// Mounts returns the mounts for the transaction identified by key. Can be
// called on an read-write or readonly transaction.
//
// This can be used to recover mounts after calling View or Prepare.
func (o *snapshotter) Mounts(ctx context.Context, key string) ([]containerd.Mount, error) {
ctx, t, err := o.ms.TransactionContext(ctx, false)
if err != nil {
return nil, err
}
active, err := storage.GetActive(ctx, key)
t.Rollback()
if err != nil {
return nil, errors.Wrap(err, "failed to get active mount")
}
return o.mounts(active), nil
}
func (o *snapshotter) Commit(ctx context.Context, name, key string) error {
ctx, t, err := o.ms.TransactionContext(ctx, true)
if err != nil {
return err
}
if _, err := storage.CommitActive(ctx, key, name); err != nil {
if rerr := t.Rollback(); rerr != nil {
log.G(ctx).WithError(rerr).Warn("Failure rolling back transaction")
}
return errors.Wrap(err, "failed to commit snapshot")
}
return t.Commit()
}
// Remove abandons the transaction identified by key. All resources
// associated with the key will be removed.
func (o *snapshotter) Remove(ctx context.Context, key string) (err error) {
ctx, t, err := o.ms.TransactionContext(ctx, true)
if err != nil {
return err
}
defer func() {
if err != nil && t != nil {
if rerr := t.Rollback(); rerr != nil {
log.G(ctx).WithError(rerr).Warn("Failure rolling back transaction")
}
}
}()
id, _, err := storage.Remove(ctx, key)
if err != nil {
return errors.Wrap(err, "failed to remove")
} }
// Move the data into our metadata directory, we could probably save disk path := o.getSnapshotDir(id)
// space if we just saved the diff, but let's get something working. renamed := filepath.Join(o.root, "snapshots", "rm-"+id)
if err := fs.CopyDir(filepath.Join(active.metadata, "data"), dst); err != nil { if err := os.Rename(path, renamed); err != nil {
return errors.Wrap(err, "copying of parent failed") if !os.IsNotExist(err) {
return errors.Wrap(err, "failed to rename")
}
renamed = ""
} }
if err := os.Rename(active.metadata, diff); err != nil { err = t.Commit()
return errors.Wrap(err, "failed to rename metadata into diff") t = nil
if err != nil {
if renamed != "" {
if err1 := os.Rename(renamed, path); err1 != nil {
// May cause inconsistent data on disk
log.G(ctx).WithError(err1).WithField("path", renamed).Errorf("Failed to rename after failed commit")
}
}
return errors.Wrap(err, "failed to commit")
}
if renamed != "" {
if err := os.RemoveAll(renamed); err != nil {
// Must be cleaned up, any "rm-*" could be removed if no active transactions
log.G(ctx).WithError(err).WithField("path", renamed).Warnf("Failed to remove root filesystem")
}
} }
n.parents[diff] = active.parent
delete(n.active, dst)
return nil return nil
} }
func (n *Naive) Rollback(dst string) error { // Walk the committed snapshots.
active, ok := n.active[dst] func (o *snapshotter) Walk(ctx context.Context, fn func(context.Context, snapshot.Info) error) error {
if !ok { ctx, t, err := o.ms.TransactionContext(ctx, false)
return fmt.Errorf("%q must be an active snapshot", dst) if err != nil {
return err
}
defer t.Rollback()
return storage.WalkInfo(ctx, fn)
}
func (o *snapshotter) createActive(ctx context.Context, key, parent string, readonly bool) ([]containerd.Mount, error) {
var (
err error
path, td string
)
if !readonly || parent == "" {
td, err = ioutil.TempDir(filepath.Join(o.root, "snapshots"), "new-")
if err != nil {
return nil, errors.Wrap(err, "failed to create temp dir")
}
defer func() {
if err != nil {
if td != "" {
if err1 := os.RemoveAll(td); err1 != nil {
err = errors.Wrapf(err, "remove failed: %v", err1)
}
}
if path != "" {
if err1 := os.RemoveAll(path); err1 != nil {
err = errors.Wrapf(err, "failed to remove path: %v", err1)
}
}
}
}()
} }
delete(n.active, dst) ctx, t, err := o.ms.TransactionContext(ctx, true)
return os.RemoveAll(active.metadata) if err != nil {
return nil, err
}
active, err := storage.CreateActive(ctx, key, parent, readonly)
if err != nil {
if rerr := t.Rollback(); rerr != nil {
log.G(ctx).WithError(rerr).Warn("Failure rolling back transaction")
}
return nil, errors.Wrap(err, "failed to create active")
}
if td != "" {
if len(active.ParentIDs) > 0 {
parent := o.getSnapshotDir(active.ParentIDs[0])
if err := fs.CopyDir(td, parent); err != nil {
return nil, errors.Wrap(err, "copying of parent failed")
}
}
path = o.getSnapshotDir(active.ID)
if err := os.Rename(td, path); err != nil {
if rerr := t.Rollback(); rerr != nil {
log.G(ctx).WithError(rerr).Warn("Failure rolling back transaction")
}
return nil, errors.Wrap(err, "failed to rename")
}
td = ""
}
if err := t.Commit(); err != nil {
return nil, errors.Wrap(err, "commit failed")
}
return o.mounts(active), nil
} }
func (n *Naive) Parent(diff string) string { func (o *snapshotter) getSnapshotDir(id string) string {
return n.parents[diff] return filepath.Join(o.root, "snapshots", id)
}
func (o *snapshotter) mounts(active storage.Active) []containerd.Mount {
var (
roFlag string
source string
)
if active.Readonly {
roFlag = "ro"
} else {
roFlag = "rw"
}
if len(active.ParentIDs) == 0 || !active.Readonly {
source = o.getSnapshotDir(active.ID)
} else {
source = o.getSnapshotDir(active.ParentIDs[0])
}
return []containerd.Mount{
{
Source: source,
Type: "bind",
Options: []string{
roFlag,
"rbind",
},
},
}
} }

View file

@ -1,92 +1,24 @@
package naive package naive
import ( import (
"io/ioutil" "context"
"os"
"path/filepath"
"testing" "testing"
"github.com/containerd/containerd" "github.com/containerd/containerd/snapshot"
"github.com/containerd/containerd/snapshot/testsuite"
"github.com/containerd/containerd/testutil" "github.com/containerd/containerd/testutil"
) )
func TestSnapshotNaiveBasic(t *testing.T) { func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
testutil.RequiresRoot(t) snapshotter, err := NewSnapshotter(root)
tmpDir, err := ioutil.TempDir("", "test-naive-")
if err != nil { if err != nil {
t.Fatal(err) return nil, nil, err
}
defer os.RemoveAll(tmpDir)
t.Log(tmpDir)
root := filepath.Join(tmpDir, "root")
n, err := NewNaive(root)
if err != nil {
t.Fatal(err)
} }
preparing := filepath.Join(tmpDir, "preparing") return snapshotter, func() {}, nil
if err := os.MkdirAll(preparing, 0777); err != nil { }
t.Fatal(err)
} func TestNaive(t *testing.T) {
testutil.RequiresRoot(t)
mounts, err := n.Prepare(preparing, "") testsuite.SnapshotterSuite(t, "Naive", newSnapshotter)
if err != nil {
t.Fatal(err)
}
if err := containerd.MountAll(mounts, preparing); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(preparing, "foo"), []byte("foo\n"), 0777); err != nil {
t.Fatal(err)
}
os.MkdirAll(preparing+"/a/b/c", 0755)
// defer os.Remove(filepath.Join(tmpDir, "foo"))
committed := filepath.Join(n.root, "committed")
if err := n.Commit(committed, preparing); err != nil {
t.Fatal(err)
}
if n.Parent(preparing) != "" {
t.Fatalf("parent of new layer should be empty, got n.Parent(%q) == %q", preparing, n.Parent(preparing))
}
next := filepath.Join(tmpDir, "nextlayer")
if err := os.MkdirAll(next, 0777); err != nil {
t.Fatal(err)
}
mounts, err = n.Prepare(next, committed)
if err != nil {
t.Fatal(err)
}
if err := containerd.MountAll(mounts, next); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(next, "bar"), []byte("bar\n"), 0777); err != nil {
t.Fatal(err)
}
// also, change content of foo to bar
if err := ioutil.WriteFile(filepath.Join(next, "foo"), []byte("bar\n"), 0777); err != nil {
t.Fatal(err)
}
os.RemoveAll(next + "/a/b")
nextCommitted := filepath.Join(n.root, "committed-next")
if err := n.Commit(nextCommitted, next); err != nil {
t.Fatal(err)
}
if n.Parent(nextCommitted) != committed {
t.Fatalf("parent of new layer should be %q, got n.Parent(%q) == %q (%#v)", committed, next, n.Parent(next), n.parents)
}
} }