move cache key into FileImporter

Signed-off-by: hillium <[email protected]>

br/pkg/restore/import.go

@@ -8,8 +8,6 @@ import (
 	"crypto/tls"
 	"fmt"
 	"math/rand"
-	"os"
-	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -101,21 +99,15 @@ type importClient struct {
 	tlsConf    *tls.Config
 
 	keepaliveConf keepalive.ClientParameters
-	cacheId       string
 }
 
 // NewImportClient returns a new ImporterClient.
 func NewImportClient(metaClient split.SplitClient, tlsConf *tls.Config, keepaliveConf keepalive.ClientParameters) ImporterClient {
-	hn, err := os.Hostname()
-	if err != nil {
-		hn = strconv.Itoa(int(rand.Int63()))
-	}
 	return &importClient{
 		metaClient:    metaClient,
 		clients:       make(map[uint64]import_sstpb.ImportSSTClient),
 		tlsConf:       tlsConf,
 		keepaliveConf: keepaliveConf,
-		cacheId:       fmt.Sprintf("BR-%s-%d-%s", time.Now().Format("20060102150405"), rand.Int63(), hn),
 	}
 }
 
@@ -152,7 +144,6 @@ func (ic *importClient) DownloadSST(
 	if err != nil {
 		return nil, errors.Trace(err)
 	}
-	req.StorageCacheId = ic.cacheId
 	return client.Download(ctx, req)
 }
 
@@ -258,6 +249,8 @@ type FileImporter struct {
 	rawStartKey        []byte
 	rawEndKey          []byte
 	supportMultiIngest bool
+
+	cacheKey string
 }
 
 // NewFileImporter returns a new file importClient.
@@ -272,6 +265,7 @@ func NewFileImporter(
 		backend:      backend,
 		importClient: importClient,
 		isRawKvMode:  isRawKvMode,
+		cacheKey:     fmt.Sprintf("BR-%s-%d", time.Now().Format("20060102150405"), rand.Int63()),
 	}
 }
 
@@ -647,6 +641,7 @@ func (importer *FileImporter) downloadSST(
 		Name:           file.GetName(),
 		RewriteRule:    rule,
 		CipherInfo:     cipher,
+		StorageCacheId: importer.cacheKey,
 	}
 	log.Debug("download SST",
 		logutil.SSTMeta(&sstMeta),
@@ -726,6 +721,7 @@ func (importer *FileImporter) downloadRawKVSST(
 		RewriteRule:    rule,
 		IsRawKv:        true,
 		CipherInfo:     cipher,
+		StorageCacheId: importer.cacheKey,
 	}
 	log.Debug("download SST", logutil.SSTMeta(&sstMeta), logutil.Region(regionInfo.Region))