perf: remove go-nanoid and rxgo

internal/jar/jar.go

@@ -1,6 +1,8 @@
 package jar
 
 import (
+	"crypto/rand"
+	"encoding/hex"
 	"errors"
 	"io"
 	"net/http"
@@ -10,7 +12,6 @@ import (
 	"flink-kube-operator/pkg"
 
 	api "github.com/logi-camp/go-flink-client"
-	gonanoid "github.com/matoous/go-nanoid/v2"
 	"go.uber.org/zap"
 )
 
@@ -46,7 +47,9 @@ func (jarFile *JarFile) Upload(flinkClient *api.Client) (fileName string, err er
 }
 
 func (jarFile *JarFile) Download() error {
-	fileName, _ := gonanoid.New()
+	randBytes := make([]byte, 16)
+	rand.Read(randBytes)
+	fileName := hex.EncodeToString(randBytes)
 	jarFile.filePath = "/tmp/" + fileName + ".jar"
 	out, err := os.Create(jarFile.filePath)
 	if err != nil {