github.com/containerd/nerdctl/v2@v2.0.0-beta.5.0.20240520001846-b5758f54fa28/pkg/ocihook/state/state.go (about) 1 /* 2 Copyright The containerd Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package state 18 19 import ( 20 "encoding/json" 21 "errors" 22 "fmt" 23 "os" 24 "path/filepath" 25 "time" 26 27 "github.com/containerd/nerdctl/v2/pkg/lockutil" 28 ) 29 30 // This is meant to store stateful informations about containers that we receive from ocihooks 31 // We are storing them inside the container statedir 32 // Note that you MUST use WithLock to perform any operation (like Read or Write). 33 // Typically: 34 // lf.WithLock(func ()error { 35 // lf.Load() 36 // // Modify something on the object 37 // lf.StartedAt = ... 38 // lf.Save() 39 // }) 40 41 const ( 42 lifecycleFile = "lifecycle.json" 43 ) 44 45 func NewLifecycleState(stateDir string) *LifecycleState { 46 return &LifecycleState{ 47 stateDir: stateDir, 48 } 49 } 50 51 type LifecycleState struct { 52 stateDir string 53 StartedAt time.Time `json:"started_at"` 54 } 55 56 func (lf *LifecycleState) WithLock(fun func() error) error { 57 err := lockutil.WithDirLock(lf.stateDir, fun) 58 if err != nil { 59 return fmt.Errorf("failed to lock state dir: %w", err) 60 } 61 62 return nil 63 } 64 65 func (lf *LifecycleState) Load() error { 66 data, err := os.ReadFile(filepath.Join(lf.stateDir, lifecycleFile)) 67 if err != nil { 68 if !errors.Is(err, os.ErrNotExist) { 69 return fmt.Errorf("unable to read lifecycle file: %w", err) 70 } 71 } else { 72 err = json.Unmarshal(data, lf) 73 if err != nil { 74 return fmt.Errorf("unable to unmarshall lifecycle data: %w", err) 75 } 76 } 77 return nil 78 } 79 80 func (lf *LifecycleState) Save() error { 81 data, err := json.Marshal(lf) 82 if err != nil { 83 return fmt.Errorf("unable to marshall lifecycle data: %w", err) 84 } 85 err = os.WriteFile(filepath.Join(lf.stateDir, lifecycleFile), data, 0600) 86 if err != nil { 87 return fmt.Errorf("unable to write lifecycle file: %w", err) 88 } 89 return nil 90 }