containerd/leases/lease.go
Wei Fu 8a388d6238 leases: support resource management
Add three methods for lease service so that the client can use it to
manage the resource by lease, not just gc.root label. With the following
methods, it is easy for client to maintain their own cache system.

```
 - AddResource(context.Context, Lease, Resource) error
 - RemoveResource(context.Context, Lease, Resource) error
 - ListResources(context.Context, Lease) ([]Resource, error)
```

And the resource is to be

```golang
type Resource {
  ID   string
  Type string
}
```

For the snapshots, the Type field will be formatted by
snapshots/%{type}, like snapshots/overlayfs.

fix: #3295

Signed-off-by: Wei Fu <fuweid89@gmail.com>
2019-05-29 11:00:32 +08:00

87 lines
2.3 KiB
Go

/*
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 leases
import (
"context"
"time"
)
// Opt is used to set options on a lease
type Opt func(*Lease) error
// DeleteOpt allows configuring a delete operation
type DeleteOpt func(context.Context, *DeleteOptions) error
// Manager is used to create, list, and remove leases
type Manager interface {
Create(context.Context, ...Opt) (Lease, error)
Delete(context.Context, Lease, ...DeleteOpt) error
List(context.Context, ...string) ([]Lease, error)
AddResource(context.Context, Lease, Resource) error
DeleteResource(context.Context, Lease, Resource) error
ListResources(context.Context, Lease) ([]Resource, error)
}
// Lease retains resources to prevent cleanup before
// the resources can be fully referenced.
type Lease struct {
ID string
CreatedAt time.Time
Labels map[string]string
}
// Resource represents low level resource of image, like content, ingest and
// snapshotter.
type Resource struct {
ID string
Type string
}
// DeleteOptions provide options on image delete
type DeleteOptions struct {
Synchronous bool
}
// SynchronousDelete is used to indicate that a lease deletion and removal of
// any unreferenced resources should occur synchronously before returning the
// result.
func SynchronousDelete(ctx context.Context, o *DeleteOptions) error {
o.Synchronous = true
return nil
}
// WithLabels sets labels on a lease
func WithLabels(labels map[string]string) Opt {
return func(l *Lease) error {
l.Labels = labels
return nil
}
}
// WithExpiration sets an expiration on the lease
func WithExpiration(d time.Duration) Opt {
return func(l *Lease) error {
if l.Labels == nil {
l.Labels = map[string]string{}
}
l.Labels["containerd.io/gc.expire"] = time.Now().Add(d).Format(time.RFC3339)
return nil
}
}