fix test unstable with try recursive make tmp

some time should wait between read service and get item

visualdl/logic/sdk_test.cc

@@ -7,13 +7,16 @@ namespace visualdl {
 struct ScalarTestHelper {
   ImHelper rim;
   ImHelper wim;
-  const std::string dir = "./tmp/1.test";
+  const std::string dir = "./tmp/sdk_test.test";
 
   void operator()(std::function<void()> read, std::function<void()> write) {
     wim.StartWriteSerice(dir, 200);
     write();
 
-    rim.StartReadService(dir, 200);
+    // should wait for the write service create log's path
+    std::this_thread::sleep_for(std::chrono::milliseconds(400));
+    rim.StartReadService(dir, 100);
+    // should wait for the read service to load "tag0" tablet into memory
     std::this_thread::sleep_for(std::chrono::milliseconds(600));
     read();
   }

visualdl/storage/storage.cc

@@ -44,7 +44,7 @@ void MemoryStorage::PersistToDisk(const std::string &dir) {
   CHECK(!dir.empty());
   storage_.set_dir(dir);
   // make a directory if not exist
-  fs::TryMkdir(dir);
+  fs::TryRecurMkdir(dir);
   // write storage out
   LOG(INFO) << "to serize meta to dir " << dir;
   fs::SerializeToFile(storage_, meta_path(dir));

visualdl/utils/filesystem.h

@@ -44,13 +44,26 @@ bool DeSerializeFromFile(T* proto, const std::string& path) {
 }
 
 void TryMkdir(const std::string& dir) {
-  VLOG(1) << "try to mkdir " << dir;
+  LOG(INFO) << "try to mkdir " << dir;
   struct stat st = {0};
   if (stat(dir.c_str(), &st) == -1) {
     ::mkdir(dir.c_str(), 0700);
   }
 }
 
+// Create a path by recursively create directries
+void TryRecurMkdir(const std::string& path) {
+  // split path by '/'
+  for (int i = 1; i < path.size() - 1; i++) {
+    if (path[i] == '/') {
+      auto dir = path.substr(0, i + 1);
+      TryMkdir(dir);
+    }
+  }
+  // the last level
+  TryMkdir(path);
+}
+
 inline void Write(const std::string& path,
                   const std::string& buffer,
                   std::ios::openmode open_mode = std::ios::binary) {