[VOL-3860] redis client support in voltha-lib-go
redis client support has been added in this patch. There are two
types client `redis` and `redis-sentinel` to connect a redis instance.
redis-sentinel is required to be able to find the master redis
instance from a redis-sentinel process. See redis-sentinel usage
https://redis.io/topics/sentinel and
https://pkg.go.dev/github.com/go-redis/redis/v8#NewFailoverClient
for more information. If there is no need to have any failover
mechanism then the redis client type is the option to choose.
Change-Id: I997ed92115a9d565df632c6dd8184b9bab77b991
diff --git a/pkg/db/kvstore/redisclient.go b/pkg/db/kvstore/redisclient.go
new file mode 100644
index 0000000..decb0a4
--- /dev/null
+++ b/pkg/db/kvstore/redisclient.go
@@ -0,0 +1,417 @@
+/*
+ * 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"
+ "strings"
+ "sync"
+ "time"
+
+ "github.com/go-redis/redis/v8"
+ "github.com/opencord/voltha-lib-go/v7/pkg/log"
+)
+
+type RedisClient struct {
+ redisAPI *redis.Client
+ keyReservations map[string]time.Duration
+ watchedChannels sync.Map
+ writeLock sync.Mutex
+ keyReservationsLock sync.RWMutex
+}
+
+func NewRedisClient(addr string, timeout time.Duration, useSentinel bool) (*RedisClient, error) {
+ var r *redis.Client
+ if !useSentinel {
+ r = redis.NewClient(&redis.Options{Addr: addr})
+ } else {
+ // Redis Master-Replicas with Sentinel, sentinel masterSet config
+ // should be set to sebaRedis
+ r = redis.NewFailoverClient(&redis.FailoverOptions{
+ MasterName: "sebaRedis",
+ SentinelAddrs: []string{addr},
+ })
+ }
+
+ reservations := make(map[string]time.Duration)
+ return &RedisClient{redisAPI: r, keyReservations: reservations}, nil
+}
+
+func (c *RedisClient) Get(ctx context.Context, key string) (*KVPair, error) {
+
+ val, err := c.redisAPI.Get(ctx, key).Result()
+ valBytes, _ := ToByte(val)
+ if err != nil {
+ return nil, nil
+ }
+ return NewKVPair(key, valBytes, "", 0, 0), nil
+}
+
+func (c *RedisClient) Put(ctx context.Context, key string, value 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 fmt.Errorf("unexpected-type-%T", value)
+ }
+
+ // 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
+ setErr := c.redisAPI.Set(ctx, key, val, 0)
+ err := setErr.Err()
+
+ if err != nil {
+ switch setErr.Err() {
+ case context.Canceled:
+ logger.Warnw(ctx, "context-cancelled", log.Fields{"error": err})
+ case context.DeadlineExceeded:
+ logger.Warnw(ctx, "context-deadline-exceeded", log.Fields{"error": err})
+ default:
+ logger.Warnw(ctx, "bad-endpoints", log.Fields{"error": err})
+ }
+ return err
+ }
+ return nil
+}
+
+func (c *RedisClient) scanAllKeysWithPrefix(ctx context.Context, key string) ([]string, error) {
+ var err error
+ allkeys := []string{}
+ cont := true
+ cursor := uint64(0)
+ matchPrefix := key + "*"
+
+ for cont {
+ // search in the first 10000 entries starting from the point indicated by the cursor
+ logger.Debugw(ctx, "redis-scan", log.Fields{"matchPrefix": matchPrefix, "cursor": cursor})
+ var keys []string
+ keys, cursor, err = c.redisAPI.Scan(context.Background(), cursor, matchPrefix, 10000).Result()
+ if err != nil {
+ return nil, err
+ }
+ if cursor == 0 {
+ // all data searched. break the loop
+ logger.Debugw(ctx, "redis-scan-ended", log.Fields{"matchPrefix": matchPrefix, "cursor": cursor})
+ cont = false
+ }
+ if len(keys) == 0 {
+ // no matched data found in this cycle. Continue to search
+ logger.Debugw(ctx, "redis-scan-no-data-found-continue", log.Fields{"matchPrefix": matchPrefix, "cursor": cursor})
+ continue
+ }
+ allkeys = append(allkeys, keys...)
+ }
+ return allkeys, nil
+}
+
+func (c *RedisClient) List(ctx context.Context, key string) (map[string]*KVPair, error) {
+ var err error
+ var keys []string
+ m := make(map[string]*KVPair)
+ var values []interface{}
+
+ if keys, err = c.scanAllKeysWithPrefix(ctx, key); err != nil {
+ return nil, err
+ }
+
+ if len(keys) != 0 {
+ values, err = c.redisAPI.MGet(ctx, keys...).Result()
+ if err != nil {
+ return nil, err
+ }
+ }
+ for i, key := range keys {
+ if valBytes, err := ToByte(values[i]); err == nil {
+ m[key] = NewKVPair(key, interface{}(valBytes), "", 0, 0)
+ }
+ }
+ return m, nil
+}
+
+func (c *RedisClient) Delete(ctx context.Context, key string) error {
+ // delete the key
+ if _, err := c.redisAPI.Del(ctx, key).Result(); err != nil {
+ logger.Errorw(ctx, "failed-to-delete-key", log.Fields{"key": key, "error": err})
+ return err
+ }
+ logger.Debugw(ctx, "key(s)-deleted", log.Fields{"key": key})
+ return nil
+}
+
+func (c *RedisClient) DeleteWithPrefix(ctx context.Context, prefixKey string) error {
+ var keys []string
+ var err error
+ if keys, err = c.scanAllKeysWithPrefix(ctx, prefixKey); err != nil {
+ return err
+ }
+ if len(keys) == 0 {
+ logger.Warn(ctx, "nothing-to-delete-from-kv", log.Fields{"key": prefixKey})
+ return nil
+ }
+ //call delete for keys
+ entryCount := int64(0)
+ start := 0
+ pageSize := 5000
+ length := len(keys)
+ for start < length {
+ end := start + pageSize
+ if end >= length {
+ end = length
+ }
+ keysToDelete := keys[start:end]
+ count := int64(0)
+ if count, err = c.redisAPI.Del(ctx, keysToDelete...).Result(); err != nil {
+ logger.Errorw(ctx, "DeleteWithPrefix method failed", log.Fields{"prefixKey": prefixKey, "numOfMatchedKeys": len(keysToDelete), "err": err})
+ return err
+ }
+ entryCount += count
+ start = end
+ }
+ logger.Debugf(ctx, "%d entries matching with the key prefix %s have been deleted successfully", entryCount, prefixKey)
+ return nil
+}
+
+func (c *RedisClient) Reserve(ctx context.Context, key string, value interface{}, ttl time.Duration) (interface{}, error) {
+ var val string
+ var er error
+ if val, er = ToString(value); er != nil {
+ return nil, fmt.Errorf("unexpected-type%T", value)
+ }
+
+ // SetNX -- Only set the key if it does not already exist.
+ c.redisAPI.SetNX(ctx, key, value, ttl)
+
+ // Check if set is successful
+ redisVal := c.redisAPI.Get(ctx, key).Val()
+ if redisVal == "" {
+ println("NULL")
+ return nil, nil
+ }
+
+ if val == redisVal {
+ // set is successful, return new reservation value
+ c.keyReservationsLock.Lock()
+ c.keyReservations[key] = ttl
+ c.keyReservationsLock.Unlock()
+ bytes, _ := ToByte(val)
+ return bytes, nil
+ } else {
+ // set is not successful, return existing reservation value
+ bytes, _ := ToByte(redisVal)
+ return bytes, nil
+ }
+
+}
+
+func (c *RedisClient) ReleaseReservation(ctx context.Context, key string) error {
+
+ redisVal := c.redisAPI.Get(ctx, key).Val()
+ if redisVal == "" {
+ return nil
+ }
+
+ // Override SetNX value with no TTL
+ _, err := c.redisAPI.Set(ctx, key, redisVal, 0).Result()
+ if err != nil {
+ delete(c.keyReservations, key)
+ } else {
+ return err
+ }
+ return nil
+
+}
+
+func (c *RedisClient) ReleaseAllReservations(ctx context.Context) error {
+ c.writeLock.Lock()
+ defer c.writeLock.Unlock()
+ for key := range c.keyReservations {
+ err := c.ReleaseReservation(ctx, key)
+ if err != nil {
+ logger.Errorw(ctx, "cannot-release-reservation", log.Fields{"key": key, "error": err})
+ return err
+ }
+ }
+ return nil
+}
+
+func (c *RedisClient) RenewReservation(ctx context.Context, key string) error {
+ c.writeLock.Lock()
+ defer c.writeLock.Unlock()
+
+ // Verify the key was reserved
+ ttl, ok := c.keyReservations[key]
+ if !ok {
+ return errors.New("key-not-reserved. Key not found")
+ }
+
+ redisVal := c.redisAPI.Get(ctx, key).Val()
+ if redisVal != "" {
+ c.redisAPI.Set(ctx, key, redisVal, ttl)
+ }
+ return nil
+}
+
+func (c *RedisClient) listenForKeyChange(ctx context.Context, redisCh <-chan *redis.Message, ch chan<- *Event, cancel context.CancelFunc) {
+ logger.Debug(ctx, "start-listening-on-channel ...")
+ defer cancel()
+ defer close(ch)
+ for msg := range redisCh {
+ words := strings.Split(msg.Channel, ":")
+ key := words[1]
+ msgType := getMessageType(msg.Payload)
+ var valBytes []byte
+ if msgType == PUT {
+ ev, _ := c.Get(ctx, key)
+ valBytes, _ = ToByte(ev.Value)
+ }
+ ch <- NewEvent(getMessageType(msg.Payload), []byte(key), valBytes, 0)
+ }
+ logger.Debug(ctx, "stop-listening-on-channel ...")
+}
+
+func getMessageType(msg string) int {
+ isPut := strings.HasSuffix(msg, "set")
+ isDel := strings.HasSuffix(msg, "del")
+ if isPut {
+ return PUT
+ } else if isDel {
+ return DELETE
+ } else {
+ return UNKNOWN
+ }
+}
+
+func (c *RedisClient) addChannelMap(key string, channelMap map[chan *Event]*redis.PubSub) []map[chan *Event]*redis.PubSub {
+
+ var channels interface{}
+ var exists bool
+
+ if channels, exists = c.watchedChannels.Load(key); exists {
+ channels = append(channels.([]map[chan *Event]*redis.PubSub), channelMap)
+ } else {
+ channels = []map[chan *Event]*redis.PubSub{channelMap}
+ }
+ c.watchedChannels.Store(key, channels)
+
+ return channels.([]map[chan *Event]*redis.PubSub)
+}
+
+func (c *RedisClient) removeChannelMap(key string, pos int) []map[chan *Event]*redis.PubSub {
+ var channels interface{}
+ var exists bool
+
+ if channels, exists = c.watchedChannels.Load(key); exists {
+ channels = append(channels.([]map[chan *Event]*redis.PubSub)[:pos], channels.([]map[chan *Event]*redis.PubSub)[pos+1:]...)
+ c.watchedChannels.Store(key, channels)
+ }
+
+ return channels.([]map[chan *Event]*redis.PubSub)
+}
+
+func (c *RedisClient) getChannelMaps(key string) ([]map[chan *Event]*redis.PubSub, bool) {
+ var channels interface{}
+ var exists bool
+
+ channels, exists = c.watchedChannels.Load(key)
+
+ if channels == nil {
+ return nil, exists
+ }
+
+ return channels.([]map[chan *Event]*redis.PubSub), exists
+}
+
+func (c *RedisClient) Watch(ctx context.Context, key string, withPrefix bool) chan *Event {
+
+ ctx, cancel := context.WithCancel(ctx)
+
+ var subscribePath string
+ subscribePath = "__key*__:" + key
+ if withPrefix {
+ subscribePath += "*"
+ }
+ pubsub := c.redisAPI.PSubscribe(ctx, subscribePath)
+ redisCh := pubsub.Channel()
+
+ // Create 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]*redis.PubSub)
+ channelMap[ch] = pubsub
+
+ channelMaps := c.addChannelMap(key, channelMap)
+ logger.Debugw(ctx, "watched-channels", log.Fields{"len": len(channelMaps)})
+
+ // Launch a go routine to listen for updates
+ go c.listenForKeyChange(ctx, redisCh, ch, cancel)
+ return ch
+}
+
+func (c *RedisClient) CloseWatch(ctx context.Context, key string, ch chan *Event) {
+ // Get the array of channels mapping
+ var watchedChannels []map[chan *Event]*redis.PubSub
+ var ok bool
+
+ if watchedChannels, ok = c.getChannelMaps(key); !ok {
+ logger.Warnw(ctx, "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 {
+ logger.Debug(ctx, "channel-found")
+ // Close the Redis watcher before the client channel. This should close the etcd channel as well
+ if err := t.Close(); err != nil {
+ logger.Errorw(ctx, "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)
+ }
+ logger.Infow(ctx, "watcher-channel-exiting", log.Fields{"key": key, "channel": channelMaps})
+}
+func (c *RedisClient) AcquireLock(ctx context.Context, lockName string, timeout time.Duration) error {
+ return nil
+}
+
+func (c *RedisClient) ReleaseLock(lockName string) error {
+ return nil
+}
+
+func (c *RedisClient) IsConnectionUp(ctx context.Context) bool {
+ if _, err := c.redisAPI.Set(ctx, "connection-check", "1", 0).Result(); err != nil {
+ return false
+ }
+ return true
+
+}
+
+func (c *RedisClient) Close(ctx context.Context) {
+ if err := c.redisAPI.Close(); err != nil {
+ logger.Errorw(ctx, "error-closing-client", log.Fields{"error": err})
+ }
+}