/
gc.go
517 lines (455 loc) · 12.8 KB
/
gc.go
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/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package metadata
import (
"bytes"
"context"
"fmt"
"strings"
"time"
"github.com/containerd/containerd/gc"
"github.com/containerd/containerd/log"
bolt "go.etcd.io/bbolt"
)
const (
// ResourceUnknown specifies an unknown resource
ResourceUnknown gc.ResourceType = iota
// ResourceContent specifies a content resource
ResourceContent
// ResourceSnapshot specifies a snapshot resource
ResourceSnapshot
// ResourceContainer specifies a container resource
ResourceContainer
// ResourceTask specifies a task resource
ResourceTask
// ResourceLease specifies a lease
ResourceLease
// ResourceIngest specifies a content ingest
ResourceIngest
)
const (
resourceContentFlat = ResourceContent | 0x20
resourceSnapshotFlat = ResourceSnapshot | 0x20
)
var (
labelGCRoot = []byte("containerd.io/gc.root")
labelGCSnapRef = []byte("containerd.io/gc.ref.snapshot.")
labelGCContentRef = []byte("containerd.io/gc.ref.content")
labelGCExpire = []byte("containerd.io/gc.expire")
labelGCFlat = []byte("containerd.io/gc.flat")
)
// scanRoots sends the given channel "root" resources that are certainly used.
// The caller could look the references of the resources to find all resources that are used.
func scanRoots(ctx context.Context, tx *bolt.Tx, nc chan<- gc.Node) error {
v1bkt := tx.Bucket(bucketKeyVersion)
if v1bkt == nil {
return nil
}
expThreshold := time.Now()
// iterate through each namespace
v1c := v1bkt.Cursor()
// cerr indicates the scan did not successfully send all
// the roots. The scan does not need to be cancelled but
// must return error at the end.
var cerr error
fn := func(n gc.Node) {
select {
case nc <- n:
case <-ctx.Done():
cerr = ctx.Err()
}
}
for k, v := v1c.First(); k != nil; k, v = v1c.Next() {
if v != nil {
continue
}
nbkt := v1bkt.Bucket(k)
ns := string(k)
lbkt := nbkt.Bucket(bucketKeyObjectLeases)
if lbkt != nil {
if err := lbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
libkt := lbkt.Bucket(k)
var flat bool
if lblbkt := libkt.Bucket(bucketKeyObjectLabels); lblbkt != nil {
if expV := lblbkt.Get(labelGCExpire); expV != nil {
exp, err := time.Parse(time.RFC3339, string(expV))
if err != nil {
// label not used, log and continue to use lease
log.G(ctx).WithError(err).WithField("lease", string(k)).Infof("ignoring invalid expiration value %q", string(expV))
} else if expThreshold.After(exp) {
// lease has expired, skip
return nil
}
}
if flatV := lblbkt.Get(labelGCFlat); flatV != nil {
flat = true
}
}
fn(gcnode(ResourceLease, ns, string(k)))
// Emit content and snapshots as roots instead of implementing
// in references. Since leases cannot be referenced there is
// no need to allow the lookup to be recursive, handling here
// therefore reduces the number of database seeks.
ctype := ResourceContent
if flat {
ctype = resourceContentFlat
}
cbkt := libkt.Bucket(bucketKeyObjectContent)
if cbkt != nil {
if err := cbkt.ForEach(func(k, v []byte) error {
fn(gcnode(ctype, ns, string(k)))
return nil
}); err != nil {
return err
}
}
stype := ResourceSnapshot
if flat {
stype = resourceSnapshotFlat
}
sbkt := libkt.Bucket(bucketKeyObjectSnapshots)
if sbkt != nil {
if err := sbkt.ForEach(func(sk, sv []byte) error {
if sv != nil {
return nil
}
snbkt := sbkt.Bucket(sk)
return snbkt.ForEach(func(k, v []byte) error {
fn(gcnode(stype, ns, fmt.Sprintf("%s/%s", sk, k)))
return nil
})
}); err != nil {
return err
}
}
ibkt := libkt.Bucket(bucketKeyObjectIngests)
if ibkt != nil {
if err := ibkt.ForEach(func(k, v []byte) error {
fn(gcnode(ResourceIngest, ns, string(k)))
return nil
}); err != nil {
return err
}
}
return nil
}); err != nil {
return err
}
}
ibkt := nbkt.Bucket(bucketKeyObjectImages)
if ibkt != nil {
if err := ibkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
target := ibkt.Bucket(k).Bucket(bucketKeyTarget)
if target != nil {
contentKey := string(target.Get(bucketKeyDigest))
fn(gcnode(ResourceContent, ns, contentKey))
}
return sendLabelRefs(ns, ibkt.Bucket(k), fn)
}); err != nil {
return err
}
}
cbkt := nbkt.Bucket(bucketKeyObjectContent)
if cbkt != nil {
ibkt := cbkt.Bucket(bucketKeyObjectIngests)
if ibkt != nil {
if err := ibkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
ea, err := readExpireAt(ibkt.Bucket(k))
if err != nil {
return err
}
if ea == nil || expThreshold.After(*ea) {
return nil
}
fn(gcnode(ResourceIngest, ns, string(k)))
return nil
}); err != nil {
return err
}
}
cbkt = cbkt.Bucket(bucketKeyObjectBlob)
if cbkt != nil {
if err := cbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
if isRootRef(cbkt.Bucket(k)) {
fn(gcnode(ResourceContent, ns, string(k)))
}
return nil
}); err != nil {
return err
}
}
}
cbkt = nbkt.Bucket(bucketKeyObjectContainers)
if cbkt != nil {
if err := cbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
cibkt := cbkt.Bucket(k)
snapshotter := string(cibkt.Get(bucketKeySnapshotter))
if snapshotter != "" {
ss := string(cibkt.Get(bucketKeySnapshotKey))
fn(gcnode(ResourceSnapshot, ns, fmt.Sprintf("%s/%s", snapshotter, ss)))
}
return sendLabelRefs(ns, cibkt, fn)
}); err != nil {
return err
}
}
sbkt := nbkt.Bucket(bucketKeyObjectSnapshots)
if sbkt != nil {
if err := sbkt.ForEach(func(sk, sv []byte) error {
if sv != nil {
return nil
}
snbkt := sbkt.Bucket(sk)
return snbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
if isRootRef(snbkt.Bucket(k)) {
fn(gcnode(ResourceSnapshot, ns, fmt.Sprintf("%s/%s", sk, k)))
}
return nil
})
}); err != nil {
return err
}
}
}
return cerr
}
// references finds the resources that are reachable from the given node.
func references(ctx context.Context, tx *bolt.Tx, node gc.Node, fn func(gc.Node)) error {
switch node.Type {
case ResourceContent:
bkt := getBucket(tx, bucketKeyVersion, []byte(node.Namespace), bucketKeyObjectContent, bucketKeyObjectBlob, []byte(node.Key))
if bkt == nil {
// Node may be created from dead edge
return nil
}
return sendLabelRefs(node.Namespace, bkt, fn)
case ResourceSnapshot, resourceSnapshotFlat:
parts := strings.SplitN(node.Key, "/", 2)
if len(parts) != 2 {
return fmt.Errorf("invalid snapshot gc key %s", node.Key)
}
ss := parts[0]
name := parts[1]
bkt := getBucket(tx, bucketKeyVersion, []byte(node.Namespace), bucketKeyObjectSnapshots, []byte(ss), []byte(name))
if bkt == nil {
// Node may be created from dead edge
return nil
}
if pv := bkt.Get(bucketKeyParent); len(pv) > 0 {
fn(gcnode(node.Type, node.Namespace, fmt.Sprintf("%s/%s", ss, pv)))
}
// Do not send labeled references for flat snapshot refs
if node.Type == resourceSnapshotFlat {
return nil
}
return sendLabelRefs(node.Namespace, bkt, fn)
case ResourceIngest:
// Send expected value
bkt := getBucket(tx, bucketKeyVersion, []byte(node.Namespace), bucketKeyObjectContent, bucketKeyObjectIngests, []byte(node.Key))
if bkt == nil {
// Node may be created from dead edge
return nil
}
// Load expected
expected := bkt.Get(bucketKeyExpected)
if len(expected) > 0 {
fn(gcnode(ResourceContent, node.Namespace, string(expected)))
}
return nil
}
return nil
}
// scanAll finds all resources regardless whether the resources are used or not.
func scanAll(ctx context.Context, tx *bolt.Tx, fn func(ctx context.Context, n gc.Node) error) error {
v1bkt := tx.Bucket(bucketKeyVersion)
if v1bkt == nil {
return nil
}
// iterate through each namespace
v1c := v1bkt.Cursor()
for k, v := v1c.First(); k != nil; k, v = v1c.Next() {
if v != nil {
continue
}
nbkt := v1bkt.Bucket(k)
ns := string(k)
lbkt := nbkt.Bucket(bucketKeyObjectLeases)
if lbkt != nil {
if err := lbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
return fn(ctx, gcnode(ResourceLease, ns, string(k)))
}); err != nil {
return err
}
}
sbkt := nbkt.Bucket(bucketKeyObjectSnapshots)
if sbkt != nil {
if err := sbkt.ForEach(func(sk, sv []byte) error {
if sv != nil {
return nil
}
snbkt := sbkt.Bucket(sk)
return snbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
node := gcnode(ResourceSnapshot, ns, fmt.Sprintf("%s/%s", sk, k))
return fn(ctx, node)
})
}); err != nil {
return err
}
}
cbkt := nbkt.Bucket(bucketKeyObjectContent)
if cbkt != nil {
ibkt := cbkt.Bucket(bucketKeyObjectIngests)
if ibkt != nil {
if err := ibkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
node := gcnode(ResourceIngest, ns, string(k))
return fn(ctx, node)
}); err != nil {
return err
}
}
cbkt = cbkt.Bucket(bucketKeyObjectBlob)
if cbkt != nil {
if err := cbkt.ForEach(func(k, v []byte) error {
if v != nil {
return nil
}
node := gcnode(ResourceContent, ns, string(k))
return fn(ctx, node)
}); err != nil {
return err
}
}
}
}
return nil
}
// remove all buckets for the given node.
func remove(ctx context.Context, tx *bolt.Tx, node gc.Node) error {
v1bkt := tx.Bucket(bucketKeyVersion)
if v1bkt == nil {
return nil
}
nsbkt := v1bkt.Bucket([]byte(node.Namespace))
if nsbkt == nil {
return nil
}
switch node.Type {
case ResourceContent:
cbkt := nsbkt.Bucket(bucketKeyObjectContent)
if cbkt != nil {
cbkt = cbkt.Bucket(bucketKeyObjectBlob)
}
if cbkt != nil {
log.G(ctx).WithField("key", node.Key).Debug("remove content")
return cbkt.DeleteBucket([]byte(node.Key))
}
case ResourceSnapshot:
sbkt := nsbkt.Bucket(bucketKeyObjectSnapshots)
if sbkt != nil {
parts := strings.SplitN(node.Key, "/", 2)
if len(parts) != 2 {
return fmt.Errorf("invalid snapshot gc key %s", node.Key)
}
ssbkt := sbkt.Bucket([]byte(parts[0]))
if ssbkt != nil {
log.G(ctx).WithField("key", parts[1]).WithField("snapshotter", parts[0]).Debug("remove snapshot")
return ssbkt.DeleteBucket([]byte(parts[1]))
}
}
case ResourceLease:
lbkt := nsbkt.Bucket(bucketKeyObjectLeases)
if lbkt != nil {
return lbkt.DeleteBucket([]byte(node.Key))
}
case ResourceIngest:
ibkt := nsbkt.Bucket(bucketKeyObjectContent)
if ibkt != nil {
ibkt = ibkt.Bucket(bucketKeyObjectIngests)
}
if ibkt != nil {
log.G(ctx).WithField("ref", node.Key).Debug("remove ingest")
return ibkt.DeleteBucket([]byte(node.Key))
}
}
return nil
}
// sendLabelRefs sends all snapshot and content references referred to by the labels in the bkt
func sendLabelRefs(ns string, bkt *bolt.Bucket, fn func(gc.Node)) error {
lbkt := bkt.Bucket(bucketKeyObjectLabels)
if lbkt != nil {
lc := lbkt.Cursor()
labelRef := string(labelGCContentRef)
for k, v := lc.Seek(labelGCContentRef); k != nil && strings.HasPrefix(string(k), labelRef); k, v = lc.Next() {
if ks := string(k); ks != labelRef {
// Allow reference naming separated by . or /, ignore names
if ks[len(labelRef)] != '.' && ks[len(labelRef)] != '/' {
continue
}
}
fn(gcnode(ResourceContent, ns, string(v)))
}
for k, v := lc.Seek(labelGCSnapRef); k != nil && strings.HasPrefix(string(k), string(labelGCSnapRef)); k, v = lc.Next() {
snapshotter := k[len(labelGCSnapRef):]
if i := bytes.IndexByte(snapshotter, '/'); i >= 0 {
snapshotter = snapshotter[:i]
}
fn(gcnode(ResourceSnapshot, ns, fmt.Sprintf("%s/%s", snapshotter, v)))
}
}
return nil
}
func isRootRef(bkt *bolt.Bucket) bool {
lbkt := bkt.Bucket(bucketKeyObjectLabels)
if lbkt != nil {
rv := lbkt.Get(labelGCRoot)
if rv != nil {
// TODO: interpret rv as a timestamp and skip if expired
return true
}
}
return false
}
func gcnode(t gc.ResourceType, ns, key string) gc.Node {
return gc.Node{
Type: t,
Namespace: ns,
Key: key,
}
}