VOL-3504 Code changes to support force delete
Change-Id: I041ab2101a607b99e0372e432819a3f10f3a774c
diff --git a/rw_core/core/device/transientstate/loader.go b/rw_core/core/device/transientstate/loader.go
new file mode 100644
index 0000000..f8710cc
--- /dev/null
+++ b/rw_core/core/device/transientstate/loader.go
@@ -0,0 +1,114 @@
+/*
+ * Copyright 2020-present Open Networking Foundation
+
+ * 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 transientstate
+
+import (
+ "context"
+ "fmt"
+ "sync"
+
+ "github.com/opencord/voltha-go/db/model"
+ "github.com/opencord/voltha-lib-go/v4/pkg/log"
+ "github.com/opencord/voltha-protos/v4/go/voltha"
+ "google.golang.org/grpc/codes"
+ "google.golang.org/grpc/status"
+)
+
+// Loader hides all low-level locking & synchronization related to device transient state updates
+type Loader struct {
+ dbProxy *model.Proxy
+ // this lock protects the device transient state
+ lock sync.RWMutex
+ deviceTransientState *data
+}
+
+type data struct {
+ transientState voltha.DeviceTransientState_Types
+ deviceID string
+}
+
+func NewLoader(dbProxy *model.Proxy, deviceID string) *Loader {
+ return &Loader{
+ dbProxy: dbProxy,
+ deviceTransientState: &data{
+ transientState: voltha.DeviceTransientState_NONE,
+ deviceID: deviceID,
+ },
+ }
+}
+
+// Load queries existing transient state from the kv,
+// and should only be called once when first created.
+func (loader *Loader) Load(ctx context.Context) {
+ loader.lock.Lock()
+ defer loader.lock.Unlock()
+
+ var deviceTransientState voltha.DeviceTransientState
+ if have, err := loader.dbProxy.Get(ctx, loader.deviceTransientState.deviceID, &deviceTransientState); err != nil || !have {
+ logger.Errorw(ctx, "failed-to-get-device-transient-state-from-cluster-data-proxy", log.Fields{"error": err})
+ return
+ }
+ loader.deviceTransientState.transientState = deviceTransientState.TransientState
+}
+
+// Lock acquires the lock for deviceTransientStateLoader, and returns a handle
+// which can be used to access it until it's unlocked.
+// This handle ensures that the deviceTransientState cannot be accessed if the lock is not held.
+// TODO: consider accepting a ctx and aborting the lock attempt on cancellation
+func (loader *Loader) Lock() *Handle {
+ loader.lock.Lock()
+ dataTransientState := loader.deviceTransientState
+ return &Handle{loader: loader, data: dataTransientState}
+}
+
+// Handle is allocated for each Lock() call, all modifications are made using it, and it is invalidated by Unlock()
+// This enforces correct Lock()-Usage()-Unlock() ordering.
+type Handle struct {
+ loader *Loader
+ data *data
+}
+
+// GetReadOnly returns device transient which MUST NOT be modified externally, but which is safe to keep indefinitely
+func (h *Handle) GetReadOnly() voltha.DeviceTransientState_Types {
+ return h.data.transientState
+}
+
+// Update updates device transient state in KV store
+// The provided device transient state must not be modified afterwards.
+func (h *Handle) Update(ctx context.Context, state voltha.DeviceTransientState_Types) error {
+ var tState voltha.DeviceTransientState
+ tState.TransientState = state
+ if err := h.loader.dbProxy.Set(ctx, fmt.Sprint(h.data.deviceID), &tState); err != nil {
+ return status.Errorf(codes.Internal, "failed-to-update-device-%v-transient-state: %s", h.data.deviceID, err)
+ }
+ h.data.transientState = state
+ return nil
+}
+
+// Delete deletes device transient state from KV store
+func (h *Handle) Delete(ctx context.Context) error {
+ if err := h.loader.dbProxy.Remove(ctx, fmt.Sprint(h.data.deviceID)); err != nil {
+ return status.Errorf(codes.Internal, "failed-to-delete-device-%v-transient-state: %s", h.data.deviceID, err)
+ }
+ return nil
+}
+
+// UnLock releases the lock on the device transient state.
+func (h *Handle) UnLock() {
+ defer h.loader.lock.Unlock()
+ h.data = nil
+}