VOL-1558 Implementation of openolt adapter with dep for dependency management
Also updated the build system to take this into account.

Currently dep ensure fails due to missing libraries in voltha-go, but the vendor folder has been updated otherwise.
This can be worked around in development using the LOCAL_VOLTHAGO variable described in the readme
This does not build currrently, but that is due to missing code in voltha-go master.

This pattern is consistent with how voltha-go does things, but does not leave you dependent on it to build.

See the readme for how to use dep.

The resourcemanager file is no longer hidden.

Change-Id: I25b8472dbc517b193970597c9f43ddff18c2d89f
diff --git a/vendor/github.com/opencord/voltha-go/db/kvstore/etcdclient.go b/vendor/github.com/opencord/voltha-go/db/kvstore/etcdclient.go
new file mode 100644
index 0000000..e5f6dfe
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-go/db/kvstore/etcdclient.go
@@ -0,0 +1,520 @@
+/*
+ * 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 kvstore
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"github.com/opencord/voltha-go/common/log"
+	v3Client "go.etcd.io/etcd/clientv3"
+	v3Concurrency "go.etcd.io/etcd/clientv3/concurrency"
+	v3rpcTypes "go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
+	"sync"
+)
+
+// EtcdClient represents the Etcd KV store client
+type EtcdClient struct {
+	ectdAPI          *v3Client.Client
+	leaderRev        v3Client.Client
+	keyReservations  map[string]*v3Client.LeaseID
+	watchedChannels  sync.Map
+	writeLock        sync.Mutex
+	lockToMutexMap   map[string]*v3Concurrency.Mutex
+	lockToSessionMap map[string]*v3Concurrency.Session
+	lockToMutexLock  sync.Mutex
+}
+
+// NewEtcdClient returns a new client for the Etcd KV store
+func NewEtcdClient(addr string, timeout int) (*EtcdClient, error) {
+	duration := GetDuration(timeout)
+
+	c, err := v3Client.New(v3Client.Config{
+		Endpoints:   []string{addr},
+		DialTimeout: duration,
+	})
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+
+	reservations := make(map[string]*v3Client.LeaseID)
+	lockMutexMap := make(map[string]*v3Concurrency.Mutex)
+	lockSessionMap := make(map[string]*v3Concurrency.Session)
+
+	return &EtcdClient{ectdAPI: c, keyReservations: reservations, lockToMutexMap: lockMutexMap,
+		lockToSessionMap: lockSessionMap}, nil
+}
+
+// List returns an array of key-value pairs with key as a prefix.  Timeout defines how long the function will
+// wait for a response
+func (c *EtcdClient) List(key string, timeout int, lock ...bool) (map[string]*KVPair, error) {
+	duration := GetDuration(timeout)
+
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+
+	// DO NOT lock by default; otherwise lock per instructed value
+	if len(lock) > 0 && lock[0] {
+		session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+		mu := v3Concurrency.NewMutex(session, "/lock"+key)
+		mu.Lock(context.Background())
+		defer mu.Unlock(context.Background())
+		defer session.Close()
+	}
+
+	resp, err := c.ectdAPI.Get(ctx, key, v3Client.WithPrefix())
+	cancel()
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+	m := make(map[string]*KVPair)
+	for _, ev := range resp.Kvs {
+		m[string(ev.Key)] = NewKVPair(string(ev.Key), ev.Value, "", ev.Lease)
+	}
+	return m, nil
+}
+
+// Get returns a key-value pair for a given key. Timeout defines how long the function will
+// wait for a response
+func (c *EtcdClient) Get(key string, timeout int, lock ...bool) (*KVPair, error) {
+	duration := GetDuration(timeout)
+
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+
+	// Lock by default; otherwise lock per instructed value
+	if len(lock) > 0 && lock[0] {
+		session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+		mu := v3Concurrency.NewMutex(session, "/lock"+key)
+		mu.Lock(context.Background())
+		defer mu.Unlock(context.Background())
+		defer session.Close()
+	}
+
+	resp, err := c.ectdAPI.Get(ctx, key)
+	cancel()
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+	for _, ev := range resp.Kvs {
+		// Only one value is returned
+		return NewKVPair(string(ev.Key), ev.Value, "", ev.Lease), nil
+	}
+	return nil, nil
+}
+
+// Put writes a key-value pair to the KV store.  Value can only be a string or []byte since the etcd API
+// accepts only a string as a value for a put operation. Timeout defines how long the function will
+// wait for a response
+func (c *EtcdClient) Put(key string, value interface{}, timeout int, lock ...bool) error {
+
+	// Validate that we can convert value to a string as etcd API expects a string
+	var val string
+	var er error
+	if val, er = ToString(value); er != nil {
+		return fmt.Errorf("unexpected-type-%T", value)
+	}
+
+	duration := GetDuration(timeout)
+
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+
+	// Lock by default; otherwise lock per instructed value
+	if len(lock) == 0 || lock[0] {
+		session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+		mu := v3Concurrency.NewMutex(session, "/lock"+key)
+		mu.Lock(context.Background())
+		defer mu.Unlock(context.Background())
+		defer session.Close()
+	}
+
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+	_, err := c.ectdAPI.Put(ctx, key, val)
+	cancel()
+	if err != nil {
+		switch err {
+		case context.Canceled:
+			log.Warnw("context-cancelled", log.Fields{"error": err})
+		case context.DeadlineExceeded:
+			log.Warnw("context-deadline-exceeded", log.Fields{"error": err})
+		case v3rpcTypes.ErrEmptyKey:
+			log.Warnw("etcd-client-error", log.Fields{"error": err})
+		default:
+			log.Warnw("bad-endpoints", log.Fields{"error": err})
+		}
+		return err
+	}
+	return nil
+}
+
+// Delete removes a key from the KV store. Timeout defines how long the function will
+// wait for a response
+func (c *EtcdClient) Delete(key string, timeout int, lock ...bool) error {
+
+	duration := GetDuration(timeout)
+
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+
+	// Lock by default; otherwise lock per instructed value
+	if len(lock) == 0 || lock[0] {
+		session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+		mu := v3Concurrency.NewMutex(session, "/lock"+key)
+		mu.Lock(context.Background())
+		defer mu.Unlock(context.Background())
+		defer session.Close()
+	}
+
+	defer cancel()
+
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+
+	// delete the keys
+	if _, err := c.ectdAPI.Delete(ctx, key, v3Client.WithPrefix()); err != nil {
+		log.Errorw("failed-to-delete-key", log.Fields{"key": key, "error": err})
+		return err
+	}
+	log.Debugw("key(s)-deleted", log.Fields{"key": key})
+	return nil
+}
+
+// Reserve is invoked to acquire a key and set it to a given value. Value can only be a string or []byte since
+// the etcd API accepts only a string.  Timeout defines how long the function will wait for a response.  TTL
+// defines how long that reservation is valid.  When TTL expires the key is unreserved by the KV store itself.
+// If the key is acquired then the value returned will be the value passed in.  If the key is already acquired
+// then the value assigned to that key will be returned.
+func (c *EtcdClient) Reserve(key string, value interface{}, ttl int64) (interface{}, error) {
+	// Validate that we can convert value to a string as etcd API expects a string
+	var val string
+	var er error
+	if val, er = ToString(value); er != nil {
+		return nil, fmt.Errorf("unexpected-type%T", value)
+	}
+
+	// Create a lease
+	resp, err := c.ectdAPI.Grant(context.Background(), ttl)
+	if err != nil {
+		log.Error(err)
+		return nil, err
+	}
+	// Register the lease id
+	c.writeLock.Lock()
+	c.keyReservations[key] = &resp.ID
+	c.writeLock.Unlock()
+
+	// Revoke lease if reservation is not successful
+	reservationSuccessful := false
+	defer func() {
+		if !reservationSuccessful {
+			if err = c.ReleaseReservation(key); err != nil {
+				log.Error("cannot-release-lease")
+			}
+		}
+	}()
+
+	// Try to grap the Key with the above lease
+	c.ectdAPI.Txn(context.Background())
+	txn := c.ectdAPI.Txn(context.Background())
+	txn = txn.If(v3Client.Compare(v3Client.Version(key), "=", 0))
+	txn = txn.Then(v3Client.OpPut(key, val, v3Client.WithLease(resp.ID)))
+	txn = txn.Else(v3Client.OpGet(key))
+	result, er := txn.Commit()
+	if er != nil {
+		return nil, er
+	}
+
+	if !result.Succeeded {
+		// Verify whether we are already the owner of that Key
+		if len(result.Responses) > 0 &&
+			len(result.Responses[0].GetResponseRange().Kvs) > 0 {
+			kv := result.Responses[0].GetResponseRange().Kvs[0]
+			if string(kv.Value) == val {
+				reservationSuccessful = true
+				return value, nil
+			}
+			return kv.Value, nil
+		}
+	} else {
+		// Read the Key to ensure this is our Key
+		m, err := c.Get(key, defaultKVGetTimeout, false)
+		if err != nil {
+			return nil, err
+		}
+		if m != nil {
+			if m.Key == key && isEqual(m.Value, value) {
+				// My reservation is successful - register it.  For now, support is only for 1 reservation per key
+				// per session.
+				reservationSuccessful = true
+				return value, nil
+			}
+			// My reservation has failed.  Return the owner of that key
+			return m.Value, nil
+		}
+	}
+	return nil, nil
+}
+
+// ReleaseAllReservations releases all key reservations previously made (using Reserve API)
+func (c *EtcdClient) ReleaseAllReservations() error {
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+	for key, leaseID := range c.keyReservations {
+		_, err := c.ectdAPI.Revoke(context.Background(), *leaseID)
+		if err != nil {
+			log.Errorw("cannot-release-reservation", log.Fields{"key": key, "error": err})
+			return err
+		}
+		delete(c.keyReservations, key)
+	}
+	return nil
+}
+
+// ReleaseReservation releases reservation for a specific key.
+func (c *EtcdClient) ReleaseReservation(key string) error {
+	// Get the leaseid using the key
+	log.Debugw("Release-reservation", log.Fields{"key":key})
+	var ok bool
+	var leaseID *v3Client.LeaseID
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+	if leaseID, ok = c.keyReservations[key]; !ok {
+		return nil
+	}
+	if leaseID != nil {
+		_, err := c.ectdAPI.Revoke(context.Background(), *leaseID)
+		if err != nil {
+			log.Error(err)
+			return err
+		}
+		delete(c.keyReservations, key)
+	}
+	return nil
+}
+
+// RenewReservation renews a reservation.  A reservation will go stale after the specified TTL (Time To Live)
+// period specified when reserving the key
+func (c *EtcdClient) RenewReservation(key string) error {
+	// Get the leaseid using the key
+	var ok bool
+	var leaseID *v3Client.LeaseID
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+	if leaseID, ok = c.keyReservations[key]; !ok {
+		return errors.New("key-not-reserved")
+	}
+
+	if leaseID != nil {
+		_, err := c.ectdAPI.KeepAliveOnce(context.Background(), *leaseID)
+		if err != nil {
+			log.Errorw("lease-may-have-expired", log.Fields{"error": err})
+			return err
+		}
+	} else {
+		return errors.New("lease-expired")
+	}
+	return nil
+}
+
+// Watch provides the watch capability on a given key.  It returns a channel onto which the callee needs to
+// listen to receive Events.
+func (c *EtcdClient) Watch(key string) chan *Event {
+	w := v3Client.NewWatcher(c.ectdAPI)
+	channel := w.Watch(context.Background(), key, v3Client.WithPrefix())
+
+	// Create a new channel
+	ch := make(chan *Event, maxClientChannelBufferSize)
+
+	// Keep track of the created channels so they can be closed when required
+	channelMap := make(map[chan *Event]v3Client.Watcher)
+	channelMap[ch] = w
+	//c.writeLock.Lock()
+	//defer c.writeLock.Unlock()
+
+	channelMaps := c.addChannelMap(key, channelMap)
+
+	log.Debugw("watched-channels", log.Fields{"channels": channelMaps})
+	// Launch a go routine to listen for updates
+	go c.listenForKeyChange(channel, ch)
+
+	return ch
+
+}
+
+func (c *EtcdClient) addChannelMap(key string, channelMap map[chan *Event]v3Client.Watcher) []map[chan *Event]v3Client.Watcher {
+	var channels interface{}
+	var exists bool
+
+	if channels, exists = c.watchedChannels.Load(key); exists {
+		channels = append(channels.([]map[chan *Event]v3Client.Watcher), channelMap)
+	} else {
+		channels = []map[chan *Event]v3Client.Watcher{channelMap}
+	}
+	c.watchedChannels.Store(key, channels)
+
+	return channels.([]map[chan *Event]v3Client.Watcher)
+}
+
+func (c *EtcdClient) removeChannelMap(key string, pos int) []map[chan *Event]v3Client.Watcher {
+	var channels interface{}
+	var exists bool
+
+	if channels, exists = c.watchedChannels.Load(key); exists {
+		channels = append(channels.([]map[chan *Event]v3Client.Watcher)[:pos], channels.([]map[chan *Event]v3Client.Watcher)[pos+1:]...)
+		c.watchedChannels.Store(key, channels)
+	}
+
+	return channels.([]map[chan *Event]v3Client.Watcher)
+}
+
+func (c *EtcdClient) getChannelMaps(key string) ([]map[chan *Event]v3Client.Watcher, bool) {
+	var channels interface{}
+	var exists bool
+
+	channels, exists = c.watchedChannels.Load(key)
+
+	if channels == nil {
+		return nil, exists
+	}
+
+	return channels.([]map[chan *Event]v3Client.Watcher), exists
+}
+
+// CloseWatch closes a specific watch. Both the key and the channel are required when closing a watch as there
+// may be multiple listeners on the same key.  The previously created channel serves as a key
+func (c *EtcdClient) CloseWatch(key string, ch chan *Event) {
+	// Get the array of channels mapping
+	var watchedChannels []map[chan *Event]v3Client.Watcher
+	var ok bool
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+
+	if watchedChannels, ok = c.getChannelMaps(key); !ok {
+		log.Warnw("key-has-no-watched-channels", log.Fields{"key": key})
+		return
+	}
+	// Look for the channels
+	var pos = -1
+	for i, chMap := range watchedChannels {
+		if t, ok := chMap[ch]; ok {
+			log.Debug("channel-found")
+			// Close the etcd watcher before the client channel.  This should close the etcd channel as well
+			if err := t.Close(); err != nil {
+				log.Errorw("watcher-cannot-be-closed", log.Fields{"key": key, "error": err})
+			}
+			close(ch)
+			pos = i
+			break
+		}
+	}
+
+	channelMaps, _ := c.getChannelMaps(key)
+	// Remove that entry if present
+	if pos >= 0 {
+		channelMaps = c.removeChannelMap(key, pos)
+	}
+	log.Infow("watcher-channel-exiting", log.Fields{"key": key, "channel": channelMaps})
+}
+
+func (c *EtcdClient) listenForKeyChange(channel v3Client.WatchChan, ch chan<- *Event) {
+	log.Debug("start-listening-on-channel ...")
+	for resp := range channel {
+		for _, ev := range resp.Events {
+			//log.Debugf("%s %q : %q\n", ev.Type, ev.Kv.Key, ev.Kv.Value)
+			ch <- NewEvent(getEventType(ev), ev.Kv.Key, ev.Kv.Value)
+		}
+	}
+	log.Debug("stop-listening-on-channel ...")
+}
+
+func getEventType(event *v3Client.Event) int {
+	switch event.Type {
+	case v3Client.EventTypePut:
+		return PUT
+	case v3Client.EventTypeDelete:
+		return DELETE
+	}
+	return UNKNOWN
+}
+
+// Close closes the KV store client
+func (c *EtcdClient) Close() {
+	c.writeLock.Lock()
+	defer c.writeLock.Unlock()
+	if err := c.ectdAPI.Close(); err != nil {
+		log.Errorw("error-closing-client", log.Fields{"error": err})
+	}
+}
+
+func (c *EtcdClient) addLockName(lockName string, lock *v3Concurrency.Mutex, session *v3Concurrency.Session) {
+	c.lockToMutexLock.Lock()
+	defer c.lockToMutexLock.Unlock()
+	c.lockToMutexMap[lockName] = lock
+	c.lockToSessionMap[lockName] = session
+}
+
+func (c *EtcdClient) deleteLockName(lockName string) {
+	c.lockToMutexLock.Lock()
+	defer c.lockToMutexLock.Unlock()
+	delete(c.lockToMutexMap, lockName)
+	delete(c.lockToSessionMap, lockName)
+}
+
+func (c *EtcdClient) getLock(lockName string) (*v3Concurrency.Mutex, *v3Concurrency.Session) {
+	c.lockToMutexLock.Lock()
+	defer c.lockToMutexLock.Unlock()
+	var lock *v3Concurrency.Mutex
+	var session *v3Concurrency.Session
+	if l, exist := c.lockToMutexMap[lockName]; exist {
+		lock = l
+	}
+	if s, exist := c.lockToSessionMap[lockName]; exist {
+		session = s
+	}
+	return lock, session
+}
+
+func (c *EtcdClient) AcquireLock(lockName string, timeout int) error {
+	duration := GetDuration(timeout)
+	ctx, cancel := context.WithTimeout(context.Background(), duration)
+	session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+	mu := v3Concurrency.NewMutex(session, "/devicelock_"+lockName)
+	if err := mu.Lock(context.Background()); err != nil {
+		return err
+	}
+	c.addLockName(lockName, mu, session)
+	cancel()
+	return nil
+}
+
+func (c *EtcdClient) ReleaseLock(lockName string) error {
+	lock, session := c.getLock(lockName)
+	var err error
+	if lock != nil {
+		if e := lock.Unlock(context.Background()); e != nil {
+			err = e
+		}
+	}
+	if session != nil {
+		if e := session.Close(); e != nil {
+			err = e
+		}
+	}
+	c.deleteLockName(lockName)
+
+	return err
+}