Himani Chawla | 2ba1c9c | 2020-10-07 13:19:03 +0530 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2020-present Open Networking Foundation |
| 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 transientstate |
| 18 | |
| 19 | import ( |
| 20 | "context" |
| 21 | "fmt" |
| 22 | "sync" |
| 23 | |
| 24 | "github.com/opencord/voltha-go/db/model" |
yasin sapli | 5458a1c | 2021-06-14 22:24:38 +0000 | [diff] [blame^] | 25 | "github.com/opencord/voltha-lib-go/v5/pkg/log" |
Himani Chawla | 2ba1c9c | 2020-10-07 13:19:03 +0530 | [diff] [blame] | 26 | "github.com/opencord/voltha-protos/v4/go/voltha" |
| 27 | "google.golang.org/grpc/codes" |
| 28 | "google.golang.org/grpc/status" |
| 29 | ) |
| 30 | |
| 31 | // Loader hides all low-level locking & synchronization related to device transient state updates |
| 32 | type Loader struct { |
| 33 | dbProxy *model.Proxy |
| 34 | // this lock protects the device transient state |
| 35 | lock sync.RWMutex |
| 36 | deviceTransientState *data |
| 37 | } |
| 38 | |
| 39 | type data struct { |
| 40 | transientState voltha.DeviceTransientState_Types |
| 41 | deviceID string |
| 42 | } |
| 43 | |
| 44 | func NewLoader(dbProxy *model.Proxy, deviceID string) *Loader { |
| 45 | return &Loader{ |
| 46 | dbProxy: dbProxy, |
| 47 | deviceTransientState: &data{ |
| 48 | transientState: voltha.DeviceTransientState_NONE, |
| 49 | deviceID: deviceID, |
| 50 | }, |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | // Load queries existing transient state from the kv, |
| 55 | // and should only be called once when first created. |
| 56 | func (loader *Loader) Load(ctx context.Context) { |
| 57 | loader.lock.Lock() |
| 58 | defer loader.lock.Unlock() |
| 59 | |
| 60 | var deviceTransientState voltha.DeviceTransientState |
khenaidoo | 7585a96 | 2021-06-10 16:15:38 -0400 | [diff] [blame] | 61 | have, err := loader.dbProxy.Get(ctx, loader.deviceTransientState.deviceID, &deviceTransientState) |
| 62 | if err != nil { |
Himani Chawla | 2ba1c9c | 2020-10-07 13:19:03 +0530 | [diff] [blame] | 63 | logger.Errorw(ctx, "failed-to-get-device-transient-state-from-cluster-data-proxy", log.Fields{"error": err}) |
| 64 | return |
| 65 | } |
khenaidoo | 7585a96 | 2021-06-10 16:15:38 -0400 | [diff] [blame] | 66 | if have { |
| 67 | loader.deviceTransientState.transientState = deviceTransientState.TransientState |
| 68 | return |
| 69 | } |
| 70 | loader.deviceTransientState.transientState = voltha.DeviceTransientState_NONE |
Himani Chawla | 2ba1c9c | 2020-10-07 13:19:03 +0530 | [diff] [blame] | 71 | } |
| 72 | |
| 73 | // Lock acquires the lock for deviceTransientStateLoader, and returns a handle |
| 74 | // which can be used to access it until it's unlocked. |
| 75 | // This handle ensures that the deviceTransientState cannot be accessed if the lock is not held. |
| 76 | // TODO: consider accepting a ctx and aborting the lock attempt on cancellation |
| 77 | func (loader *Loader) Lock() *Handle { |
| 78 | loader.lock.Lock() |
| 79 | dataTransientState := loader.deviceTransientState |
| 80 | return &Handle{loader: loader, data: dataTransientState} |
| 81 | } |
| 82 | |
| 83 | // Handle is allocated for each Lock() call, all modifications are made using it, and it is invalidated by Unlock() |
| 84 | // This enforces correct Lock()-Usage()-Unlock() ordering. |
| 85 | type Handle struct { |
| 86 | loader *Loader |
| 87 | data *data |
| 88 | } |
| 89 | |
| 90 | // GetReadOnly returns device transient which MUST NOT be modified externally, but which is safe to keep indefinitely |
| 91 | func (h *Handle) GetReadOnly() voltha.DeviceTransientState_Types { |
| 92 | return h.data.transientState |
| 93 | } |
| 94 | |
| 95 | // Update updates device transient state in KV store |
| 96 | // The provided device transient state must not be modified afterwards. |
| 97 | func (h *Handle) Update(ctx context.Context, state voltha.DeviceTransientState_Types) error { |
| 98 | var tState voltha.DeviceTransientState |
| 99 | tState.TransientState = state |
| 100 | if err := h.loader.dbProxy.Set(ctx, fmt.Sprint(h.data.deviceID), &tState); err != nil { |
| 101 | return status.Errorf(codes.Internal, "failed-to-update-device-%v-transient-state: %s", h.data.deviceID, err) |
| 102 | } |
| 103 | h.data.transientState = state |
| 104 | return nil |
| 105 | } |
| 106 | |
| 107 | // Delete deletes device transient state from KV store |
| 108 | func (h *Handle) Delete(ctx context.Context) error { |
| 109 | if err := h.loader.dbProxy.Remove(ctx, fmt.Sprint(h.data.deviceID)); err != nil { |
| 110 | return status.Errorf(codes.Internal, "failed-to-delete-device-%v-transient-state: %s", h.data.deviceID, err) |
| 111 | } |
| 112 | return nil |
| 113 | } |
| 114 | |
| 115 | // UnLock releases the lock on the device transient state. |
| 116 | func (h *Handle) UnLock() { |
| 117 | defer h.loader.lock.Unlock() |
| 118 | h.data = nil |
| 119 | } |