Feat: etcd filer store keys should have customizable prefix (#4484)

An etcd cluster is not necessarily only dedicated to seaweedfs.
This security enhancement adds a customizable key_prefix option to the etcd filer store.
This will allow an etcd cluster administrator to limit the seaweedfs etcd user to only read/write a subset of keys under the
key_prefix, instead of all keys on the etcd cluster.

weed/command/scaffold/filer.toml

@@ -264,6 +264,7 @@ enabled = false
 servers = "localhost:2379"
 username = ""
 password = ""
+key_prefix = "seaweedfs."
 timeout = "3s"
 
 [mongodb]

weed/filer/etcd/etcd_store.go

@@ -25,6 +25,7 @@ func init() {
 
 type EtcdStore struct {
 	client *clientv3.Client
+	etcdKeyPrefix string
 }
 
 func (store *EtcdStore) GetName() string {
@@ -39,6 +40,7 @@ func (store *EtcdStore) Initialize(configuration weed_util.Configuration, prefix
 
         username := configuration.GetString(prefix + "username")
         password := configuration.GetString(prefix + "password")
+        store.etcdKeyPrefix = configuration.GetString(prefix + "key_prefix")
 
 	timeout := configuration.GetString(prefix + "timeout")
 	if timeout == "" {
@@ -91,7 +93,7 @@ func (store *EtcdStore) InsertEntry(ctx context.Context, entry *filer.Entry) (er
 		meta = weed_util.MaybeGzipData(meta)
 	}
 
-	if _, err := store.client.Put(ctx, string(key), string(meta)); err != nil {
+	if _, err := store.client.Put(ctx, store.etcdKeyPrefix + string(key), string(meta)); err != nil {
 		return fmt.Errorf("persisting %s : %v", entry.FullPath, err)
 	}
 
@@ -105,7 +107,7 @@ func (store *EtcdStore) UpdateEntry(ctx context.Context, entry *filer.Entry) (er
 func (store *EtcdStore) FindEntry(ctx context.Context, fullpath weed_util.FullPath) (entry *filer.Entry, err error) {
 	key := genKey(fullpath.DirAndName())
 
-	resp, err := store.client.Get(ctx, string(key))
+	resp, err := store.client.Get(ctx, store.etcdKeyPrefix + string(key))
 	if err != nil {
 		return nil, fmt.Errorf("get %s : %v", fullpath, err)
 	}
@@ -128,7 +130,7 @@ func (store *EtcdStore) FindEntry(ctx context.Context, fullpath weed_util.FullPa
 func (store *EtcdStore) DeleteEntry(ctx context.Context, fullpath weed_util.FullPath) (err error) {
 	key := genKey(fullpath.DirAndName())
 
-	if _, err := store.client.Delete(ctx, string(key)); err != nil {
+	if _, err := store.client.Delete(ctx, store.etcdKeyPrefix + string(key)); err != nil {
 		return fmt.Errorf("delete %s : %v", fullpath, err)
 	}
 
@@ -138,7 +140,7 @@ func (store *EtcdStore) DeleteEntry(ctx context.Context, fullpath weed_util.Full
 func (store *EtcdStore) DeleteFolderChildren(ctx context.Context, fullpath weed_util.FullPath) (err error) {
 	directoryPrefix := genDirectoryKeyPrefix(fullpath, "")
 
-	if _, err := store.client.Delete(ctx, string(directoryPrefix), clientv3.WithPrefix()); err != nil {
+	if _, err := store.client.Delete(ctx, store.etcdKeyPrefix + string(directoryPrefix), clientv3.WithPrefix()); err != nil {
 		return fmt.Errorf("deleteFolderChildren %s : %v", fullpath, err)
 	}
 
@@ -156,7 +158,7 @@ func (store *EtcdStore) ListDirectoryEntries(ctx context.Context, dirPath weed_u
 		lastFileStart = genDirectoryKeyPrefix(dirPath, startFileName)
 	}
 
-	resp, err := store.client.Get(ctx, string(lastFileStart),
+	resp, err := store.client.Get(ctx, store.etcdKeyPrefix + string(lastFileStart),
 		clientv3.WithFromKey(), clientv3.WithLimit(limit+1))
 	if err != nil {
 		return lastFileName, fmt.Errorf("list %s : %v", dirPath, err)

weed/filer/etcd/etcd_store_kv.go

@@ -8,7 +8,7 @@ import (
 
 func (store *EtcdStore) KvPut(ctx context.Context, key []byte, value []byte) (err error) {
 
-	_, err = store.client.Put(ctx, string(key), string(value))
+	_, err = store.client.Put(ctx, store.etcdKeyPrefix + string(key), string(value))
 
 	if err != nil {
 		return fmt.Errorf("kv put: %v", err)
@@ -19,7 +19,7 @@ func (store *EtcdStore) KvPut(ctx context.Context, key []byte, value []byte) (er
 
 func (store *EtcdStore) KvGet(ctx context.Context, key []byte) (value []byte, err error) {
 
-	resp, err := store.client.Get(ctx, string(key))
+	resp, err := store.client.Get(ctx, store.etcdKeyPrefix + string(key))
 
 	if err != nil {
 		return nil, fmt.Errorf("kv get: %v", err)
@@ -34,7 +34,7 @@ func (store *EtcdStore) KvGet(ctx context.Context, key []byte) (value []byte, er
 
 func (store *EtcdStore) KvDelete(ctx context.Context, key []byte) (err error) {
 
-	_, err = store.client.Delete(ctx, string(key))
+	_, err = store.client.Delete(ctx, store.etcdKeyPrefix + string(key))
 
 	if err != nil {
 		return fmt.Errorf("kv delete: %v", err)