[VOL-4291] OfAgent changes for gRPC migration
Change-Id: I8da1db6df49d478ef24ec8f9bd719e9692f48a7f
diff --git a/vendor/github.com/opencord/voltha-lib-go/v7/pkg/db/kvstore/etcdpool.go b/vendor/github.com/opencord/voltha-lib-go/v7/pkg/db/kvstore/etcdpool.go
new file mode 100644
index 0000000..4d33c27
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-lib-go/v7/pkg/db/kvstore/etcdpool.go
@@ -0,0 +1,240 @@
+/*
+ * Copyright 2021-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 (
+ "container/list"
+ "context"
+ "errors"
+ "sync"
+ "time"
+
+ "github.com/opencord/voltha-lib-go/v7/pkg/log"
+ "go.etcd.io/etcd/clientv3"
+)
+
+// EtcdClientAllocator represents a generic interface to allocate an Etcd Client
+type EtcdClientAllocator interface {
+ Get(context.Context) (*clientv3.Client, error)
+ Put(*clientv3.Client)
+ Close(ctx context.Context)
+}
+
+// NewRoundRobinEtcdClientAllocator creates a new ETCD Client Allocator using a Round Robin scheme
+func NewRoundRobinEtcdClientAllocator(endpoints []string, timeout time.Duration, capacity, maxUsage int, level log.LogLevel) (EtcdClientAllocator, error) {
+ return &roundRobin{
+ all: make(map[*clientv3.Client]*rrEntry),
+ full: make(map[*clientv3.Client]*rrEntry),
+ waitList: list.New(),
+ max: maxUsage,
+ capacity: capacity,
+ timeout: timeout,
+ endpoints: endpoints,
+ logLevel: level,
+ closingCh: make(chan struct{}, capacity*maxUsage),
+ stopCh: make(chan struct{}),
+ }, nil
+}
+
+type rrEntry struct {
+ client *clientv3.Client
+ count int
+ age time.Time
+}
+
+type roundRobin struct {
+ //block chan struct{}
+ sync.Mutex
+ available []*rrEntry
+ all map[*clientv3.Client]*rrEntry
+ full map[*clientv3.Client]*rrEntry
+ waitList *list.List
+ max int
+ capacity int
+ timeout time.Duration
+ //ageOut time.Duration
+ endpoints []string
+ size int
+ logLevel log.LogLevel
+ closing bool
+ closingCh chan struct{}
+ stopCh chan struct{}
+}
+
+// Get returns an Etcd client. If not is available, it will create one
+// until the maximum allowed capacity. If maximum capacity has been
+// reached then it will wait until s used one is freed.
+func (r *roundRobin) Get(ctx context.Context) (*clientv3.Client, error) {
+ r.Lock()
+
+ if r.closing {
+ r.Unlock()
+ return nil, errors.New("pool-is-closing")
+ }
+
+ // first determine if we need to block, which would mean the
+ // available queue is empty and we are at capacity
+ if len(r.available) == 0 && r.size >= r.capacity {
+
+ // create a channel on which to wait and
+ // add it to the list
+ ch := make(chan struct{})
+ element := r.waitList.PushBack(ch)
+ r.Unlock()
+
+ // block until it is our turn or context
+ // expires or is canceled
+ select {
+ case <-r.stopCh:
+ logger.Info(ctx, "stop-waiting-pool-is-closing")
+ r.waitList.Remove(element)
+ return nil, errors.New("stop-waiting-pool-is-closing")
+ case <-ch:
+ r.waitList.Remove(element)
+ case <-ctx.Done():
+ r.waitList.Remove(element)
+ return nil, ctx.Err()
+ }
+ r.Lock()
+ }
+
+ defer r.Unlock()
+ if len(r.available) > 0 {
+ // pull off back end as it is operationally quicker
+ last := len(r.available) - 1
+ entry := r.available[last]
+ entry.count++
+ if entry.count >= r.max {
+ r.available = r.available[:last]
+ r.full[entry.client] = entry
+ }
+ entry.age = time.Now()
+ return entry.client, nil
+ }
+
+ logConfig := log.ConstructZapConfig(log.JSON, r.logLevel, log.Fields{})
+ // increase capacity
+ client, err := clientv3.New(clientv3.Config{
+ Endpoints: r.endpoints,
+ DialTimeout: r.timeout,
+ LogConfig: &logConfig,
+ })
+ if err != nil {
+ return nil, err
+ }
+ entry := &rrEntry{
+ client: client,
+ count: 1,
+ }
+ r.all[entry.client] = entry
+
+ if r.max > 1 {
+ r.available = append(r.available, entry)
+ } else {
+ r.full[entry.client] = entry
+ }
+ r.size++
+ return client, nil
+}
+
+// Put returns the Etcd Client back to the pool
+func (r *roundRobin) Put(client *clientv3.Client) {
+ r.Lock()
+
+ entry := r.all[client]
+ entry.count--
+
+ if r.closing {
+ // Close client if count is 0
+ if entry.count == 0 {
+ if err := entry.client.Close(); err != nil {
+ logger.Warnw(context.Background(), "error-closing-client", log.Fields{"error": err})
+ }
+ delete(r.all, entry.client)
+ }
+ // Notify Close function that a client was returned to the pool
+ r.closingCh <- struct{}{}
+ r.Unlock()
+ return
+ }
+
+ // This entry is now available for use, so
+ // if in full map add it to available and
+ // remove from full
+ if _, ok := r.full[client]; ok {
+ r.available = append(r.available, entry)
+ delete(r.full, client)
+ }
+
+ front := r.waitList.Front()
+ if front != nil {
+ ch := r.waitList.Remove(front)
+ r.Unlock()
+ // need to unblock if someone is waiting
+ ch.(chan struct{}) <- struct{}{}
+ return
+ }
+ r.Unlock()
+}
+
+func (r *roundRobin) Close(ctx context.Context) {
+ r.Lock()
+ r.closing = true
+
+ // Notify anyone waiting for a client to stop waiting
+ close(r.stopCh)
+
+ // Clean-up unused clients
+ for i := 0; i < len(r.available); i++ {
+ // Count 0 means no one is using that client
+ if r.available[i].count == 0 {
+ if err := r.available[i].client.Close(); err != nil {
+ logger.Warnw(ctx, "failure-closing-client", log.Fields{"client": r.available[i].client, "error": err})
+ }
+ // Remove client for all list
+ delete(r.all, r.available[i].client)
+ }
+ }
+
+ // Figure out how many clients are in use
+ numberInUse := 0
+ for _, rrEntry := range r.all {
+ numberInUse += rrEntry.count
+ }
+ r.Unlock()
+
+ if numberInUse == 0 {
+ logger.Info(ctx, "no-connection-in-use")
+ return
+ }
+
+ logger.Infow(ctx, "waiting-for-clients-return", log.Fields{"count": numberInUse})
+
+ // Wait for notifications when a client is returned to the pool
+ for {
+ select {
+ case <-r.closingCh:
+ numberInUse--
+ if numberInUse == 0 {
+ logger.Info(ctx, "all-connections-closed")
+ return
+ }
+ case <-ctx.Done():
+ logger.Warnw(ctx, "context-done", log.Fields{"error": ctx.Err()})
+ return
+ }
+ }
+}