VOL-2640 Restructure openolt-adapter repo to best practices
Change-Id: Icead31e8ecb82ec75a22e66361fbf83f80136589
diff --git a/internal/pkg/core/olt_state_transitions.go b/internal/pkg/core/olt_state_transitions.go
new file mode 100644
index 0000000..c10d17d
--- /dev/null
+++ b/internal/pkg/core/olt_state_transitions.go
@@ -0,0 +1,187 @@
+/*
+ * Copyright 2018-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 core provides the utility for olt devices, flows and statistics
+package core
+
+import (
+ "context"
+ "reflect"
+ "runtime"
+
+ "github.com/opencord/voltha-lib-go/v3/pkg/log"
+)
+
+// DeviceState OLT Device state
+type DeviceState int
+
+const (
+ // deviceStateNull OLT is not instantiated
+ deviceStateNull DeviceState = iota
+ // deviceStateInit OLT is instantiated
+ deviceStateInit
+ // deviceStateConnected Grpc session established with OLT
+ deviceStateConnected
+ // deviceStateUp Admin state of OLT is UP
+ deviceStateUp
+ // deviceStateDown Admin state of OLT is down
+ deviceStateDown
+)
+
+// Trigger for changing the state
+type Trigger int
+
+const (
+ // DeviceInit Go to Device init state
+ DeviceInit Trigger = iota
+ // GrpcConnected Go to connected state
+ GrpcConnected
+ // DeviceUpInd Go to Device up state
+ DeviceUpInd
+ // DeviceDownInd Go to Device down state
+ DeviceDownInd
+ // GrpcDisconnected Go to Device init state
+ GrpcDisconnected
+)
+
+// TransitionHandler function type for handling transition
+type TransitionHandler func(ctx context.Context) error
+
+// Transition to store state machine
+type Transition struct {
+ previousState []DeviceState
+ currentState DeviceState
+ before []TransitionHandler
+ after []TransitionHandler
+}
+
+// TransitionMap to store all the states and current device state
+type TransitionMap struct {
+ transitions map[Trigger]Transition
+ currentDeviceState DeviceState
+}
+
+// OpenoltDevice state machine:
+//
+// null ----> init ------> connected -----> up -----> down
+// ^ ^ | ^ | |
+// | | | | | |
+// | +-------------+ +---------+ |
+// | |
+// +-----------------------------------------+
+
+// NewTransitionMap create a new state machine with all the transitions
+func NewTransitionMap(dh *DeviceHandler) *TransitionMap {
+ var transitionMap TransitionMap
+ transitionMap.currentDeviceState = deviceStateNull
+ transitionMap.transitions = make(map[Trigger]Transition)
+ // In doInit establish the grpc session
+ transitionMap.transitions[DeviceInit] =
+ Transition{
+ previousState: []DeviceState{deviceStateNull, deviceStateDown},
+ currentState: deviceStateInit,
+ before: []TransitionHandler{dh.doStateInit},
+ after: []TransitionHandler{dh.postInit}}
+ // If gRpc session fails, re-establish the grpc session
+ transitionMap.transitions[GrpcDisconnected] =
+ Transition{
+ previousState: []DeviceState{deviceStateConnected, deviceStateDown},
+ currentState: deviceStateInit,
+ before: []TransitionHandler{dh.doStateInit},
+ after: []TransitionHandler{dh.postInit}}
+ // in doConnected, create logical device and read the indications
+ transitionMap.transitions[GrpcConnected] =
+ Transition{
+ previousState: []DeviceState{deviceStateInit},
+ currentState: deviceStateConnected,
+ before: []TransitionHandler{dh.doStateConnected}}
+
+ // Once the olt UP is indication received, then do state up
+ transitionMap.transitions[DeviceUpInd] =
+ Transition{
+ previousState: []DeviceState{deviceStateConnected, deviceStateDown},
+ currentState: deviceStateUp,
+ before: []TransitionHandler{dh.doStateUp}}
+ // If olt DOWN indication comes then do sate down
+ transitionMap.transitions[DeviceDownInd] =
+ Transition{
+ previousState: []DeviceState{deviceStateUp},
+ currentState: deviceStateDown,
+ before: []TransitionHandler{dh.doStateDown}}
+
+ return &transitionMap
+}
+
+// funcName gets the handler function name
+func funcName(f interface{}) string {
+ p := reflect.ValueOf(f).Pointer()
+ rf := runtime.FuncForPC(p)
+ return rf.Name()
+}
+
+// isValidTransition checks for the new state transition is valid from current state
+func (tMap *TransitionMap) isValidTransition(trigger Trigger) bool {
+ // Validate the state transition
+ for _, state := range tMap.transitions[trigger].previousState {
+ if tMap.currentDeviceState == state {
+ return true
+ }
+ }
+ return false
+}
+
+// Handle moves the state machine to next state based on the trigger and invokes the before and
+// after handlers if the transition is a valid transition
+func (tMap *TransitionMap) Handle(ctx context.Context, trigger Trigger) {
+
+ // Check whether the transtion is valid from current state
+ if !tMap.isValidTransition(trigger) {
+ log.Errorw("Invalid transition triggered ", log.Fields{"CurrentState": tMap.currentDeviceState, "Trigger": trigger})
+ return
+ }
+
+ // Invoke the before handlers
+ beforeHandlers := tMap.transitions[trigger].before
+ if beforeHandlers == nil {
+ log.Debugw("No handlers for before", log.Fields{"trigger": trigger})
+ }
+ for _, handler := range beforeHandlers {
+ log.Debugw("running-before-handler", log.Fields{"handler": funcName(handler)})
+ if err := handler(ctx); err != nil {
+ // TODO handle error
+ log.Error(err)
+ return
+ }
+ }
+
+ // Update the state
+ tMap.currentDeviceState = tMap.transitions[trigger].currentState
+ log.Debugw("Updated device state ", log.Fields{"CurrentDeviceState": tMap.currentDeviceState})
+
+ // Invoke the after handlers
+ afterHandlers := tMap.transitions[trigger].after
+ if afterHandlers == nil {
+ log.Debugw("No handlers for after", log.Fields{"trigger": trigger})
+ }
+ for _, handler := range afterHandlers {
+ log.Debugw("running-after-handler", log.Fields{"handler": funcName(handler)})
+ if err := handler(ctx); err != nil {
+ // TODO handle error
+ log.Error(err)
+ return
+ }
+ }
+}