First voltha-go commit. This commit is focussed on setting up the voltha-go structure as well as the kvstore library
diff --git a/db/kvstore/etcdclient.go b/db/kvstore/etcdclient.go
new file mode 100644
index 0000000..2755cd1
--- /dev/null
+++ b/db/kvstore/etcdclient.go
@@ -0,0 +1,378 @@
+package kvstore
+
+import (
+ //log "../common"
+ "context"
+ "errors"
+ "sync"
+ log "github.com/opencord/voltha-go/common/log"
+ "fmt"
+ v3Client "github.com/coreos/etcd/clientv3"
+ v3rpcTypes "github.com/coreos/etcd/etcdserver/api/v3rpc/rpctypes"
+)
+
+// EtcdClient represents the Etcd KV store client
+type EtcdClient struct {
+ ectdAPI *v3Client.Client
+ leaderRev v3Client.Client
+ keyReservations map[string]*v3Client.LeaseID
+ watchedChannels map[string][]map[chan *Event]v3Client.Watcher
+ writeLock 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
+ }
+ wc := make(map[string][]map[chan *Event]v3Client.Watcher)
+ reservations := make(map[string]*v3Client.LeaseID)
+ return &EtcdClient{ectdAPI: c, watchedChannels: wc, keyReservations: reservations}, 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) (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)
+ }
+ 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) (*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), 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) 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()
+ _, 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) error {
+
+ duration := GetDuration(timeout)
+
+ ctx, cancel := context.WithTimeout(context.Background(), duration)
+ defer cancel()
+
+ c.writeLock.Lock()
+ defer c.writeLock.Unlock()
+
+ // count keys about to be deleted
+ gresp, err := c.ectdAPI.Get(ctx, key, v3Client.WithPrefix())
+ if err != nil {
+ log.Error(err)
+ return err
+ }
+
+ // delete the keys
+ dresp, err := c.ectdAPI.Delete(ctx, key, v3Client.WithPrefix())
+ if err != nil {
+ log.Error(err)
+ return err
+ }
+
+ if dresp == nil || gresp == nil {
+ log.Debug("nothing-to-delete")
+ return nil
+ }
+
+ log.Debugw("delete-keys", log.Fields{"all-keys-deleted":int64(len(gresp.Kvs)) == dresp.Deleted})
+ if int64(len(gresp.Kvs)) == dresp.Deleted {
+ log.Debug("All-keys-deleted")
+ } else {
+ log.Error("not-all-keys-deleted")
+ err := errors.New("not-all-keys-deleted")
+ return err
+ }
+ 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.Errorf("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)
+ 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
+ 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.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()
+ c.watchedChannels[key] = append(c.watchedChannels[key], channelMap)
+
+ log.Debugw("watched-channels", log.Fields{"channels":c.watchedChannels[key]})
+ // Launch a go routine to listen for updates
+ go c.listenForKeyChange(channel, ch)
+
+ return ch
+
+}
+
+// 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.watchedChannels[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
+ }
+ }
+ // Remove that entry if present
+ if pos >= 0 {
+ c.watchedChannels[key] = append(c.watchedChannels[key][:pos], c.watchedChannels[key][pos+1:]...)
+ }
+ log.Infow("watcher-channel-exiting", log.Fields{"key":key, "channel":c.watchedChannels[key]})
+}
+
+func (c *EtcdClient) listenForKeyChange(channel v3Client.WatchChan, ch chan<- *Event) {
+ log.Infow("start-listening-on-channel", log.Fields{"channel":ch})
+ 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.Info("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})
+ }
+}