github.com/containerd/containerd@v22.0.0-20200918172823-438c87b8e050+incompatible/snapshots/overlay/plugin/plugin.go (about)

     1  // +build linux
     2  
     3  /*
     4     Copyright The containerd Authors.
     5  
     6     Licensed under the Apache License, Version 2.0 (the "License");
     7     you may not use this file except in compliance with the License.
     8     You may obtain a copy of the License at
     9  
    10         http://www.apache.org/licenses/LICENSE-2.0
    11  
    12     Unless required by applicable law or agreed to in writing, software
    13     distributed under the License is distributed on an "AS IS" BASIS,
    14     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15     See the License for the specific language governing permissions and
    16     limitations under the License.
    17  */
    18  
    19  package overlay
    20  
    21  import (
    22  	"errors"
    23  
    24  	"github.com/containerd/containerd/platforms"
    25  	"github.com/containerd/containerd/plugin"
    26  	"github.com/containerd/containerd/snapshots/overlay"
    27  )
    28  
    29  // Config represents configuration for the overlay plugin.
    30  type Config struct {
    31  	// Root directory for the plugin
    32  	RootPath string `toml:"root_path"`
    33  }
    34  
    35  func init() {
    36  	plugin.Register(&plugin.Registration{
    37  		Type:   plugin.SnapshotPlugin,
    38  		ID:     "overlayfs",
    39  		Config: &Config{},
    40  		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
    41  			ic.Meta.Platforms = append(ic.Meta.Platforms, platforms.DefaultSpec())
    42  
    43  			config, ok := ic.Config.(*Config)
    44  			if !ok {
    45  				return nil, errors.New("invalid overlay configuration")
    46  			}
    47  
    48  			root := ic.Root
    49  			if config.RootPath != "" {
    50  				root = config.RootPath
    51  			}
    52  
    53  			ic.Meta.Exports["root"] = root
    54  			return overlay.NewSnapshotter(root, overlay.AsynchronousRemove)
    55  		},
    56  	})
    57  }