Fix a bug in get_vdl_log_file when logdir does not exist (#1002)

Author: rainyfly

visualdl/server/serve.py

@@ -64,17 +64,17 @@ def get_vdl_log_file(logdirs):
                             "exp2": "vdlrecords.1587375685.log"}
     """
     walks = {}
+    walks_temp = {}
     for logdir in logdirs:
         for root, dirs, files in bfile.walk(logdir):
             walks.update({root: files})
 
-            walks_temp = {}
-            for run, tags in walks.items():
-                tags_temp = [tag for tag in tags if
-                             is_VDLRecord_file(path=bfile.join(run, tag), check=False)]
-                tags_temp.sort(reverse=True)
-                if len(tags_temp) > 0:
-                    walks_temp.update({run: tags_temp[0]})
+    for run, tags in walks.items():
+        tags_temp = [tag for tag in tags if
+                     is_VDLRecord_file(path=bfile.join(run, tag), check=False)]
+        tags_temp.sort(reverse=True)
+        if len(tags_temp) > 0:
+            walks_temp.update({run: tags_temp[0]})
 
     return walks_temp