VOL-2017 voltha-lib moved from voltha-go;
release version 2.2.1
Based on voltha-go commit 5259f8e52b3e3f5c7ad422a4b0e506e1d07f6b36
Change-Id: I8bbecdf456e420714a4016120eafc0d237c80565
diff --git a/pkg/db/kvstore/etcdclient.go b/pkg/db/kvstore/etcdclient.go
new file mode 100644
index 0000000..a04dadc
--- /dev/null
+++ b/pkg/db/kvstore/etcdclient.go
@@ -0,0 +1,504 @@
+/*
+ * 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-lib-go/pkg/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
+}
+
+// IsConnectionUp returns whether the connection to the Etcd KV store is up. If a timeout occurs then
+// it is assumed the connection is down or unreachable.
+func (c *EtcdClient) IsConnectionUp(timeout int) bool {
+ // Let's try to get a non existent key. If the connection is up then there will be no error returned.
+ if _, err := c.Get("non-existent-key", timeout); err != nil {
+ return false
+ }
+ return true
+}
+
+// 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)
+
+ 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, ev.Version)
+ }
+ 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)
+
+ 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, ev.Version), 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)
+
+ c.writeLock.Lock()
+ defer c.writeLock.Unlock()
+
+ var err error
+ // Check if there is already a lease for this key - if there is then use it, otherwise a PUT will make
+ // that KV key permanent instead of automatically removing it after a lease expiration
+ if leaseID, ok := c.keyReservations[key]; ok {
+ _, err = c.ectdAPI.Put(ctx, key, val, v3Client.WithLease(*leaseID))
+ } else {
+ _, 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)
+
+ defer cancel()
+
+ c.writeLock.Lock()
+ defer c.writeLock.Unlock()
+
+ // delete the key
+ if _, err := c.ectdAPI.Delete(ctx, key); 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)
+ ctx, cancel := context.WithCancel(context.Background())
+ channel := w.Watch(ctx, key)
+
+ // 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
+
+ channelMaps := c.addChannelMap(key, channelMap)
+
+ // Changing the log field (from channelMaps) as the underlying logger cannot format the map of channels into a
+ // json format.
+ log.Debugw("watched-channels", log.Fields{"len": len(channelMaps)})
+ // Launch a go routine to listen for updates
+ go c.listenForKeyChange(channel, ch, cancel)
+
+ 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})
+ }
+ 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, cancel context.CancelFunc) {
+ log.Debug("start-listening-on-channel ...")
+ defer cancel()
+ defer close(ch)
+ for resp := range channel {
+ for _, ev := range resp.Events {
+ ch <- NewEvent(getEventType(ev), ev.Kv.Key, ev.Kv.Value, ev.Kv.Version)
+ }
+ }
+ 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)
+ defer cancel()
+ session, _ := v3Concurrency.NewSession(c.ectdAPI, v3Concurrency.WithContext(ctx))
+ mu := v3Concurrency.NewMutex(session, "/devicelock_"+lockName)
+ if err := mu.Lock(context.Background()); err != nil {
+ cancel()
+ return err
+ }
+ c.addLockName(lockName, mu, session)
+ 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
+}