Merge pull request #2206 from Suor/ssh-race

remote: fix race in and optimize SSHConnection.makedirs()

dvc/remote/ssh/connection.py

@@ -1,6 +1,7 @@
 import os
 import posixpath
 import logging
+import errno
 import stat
 from contextlib import contextmanager
 
@@ -96,10 +97,13 @@ class SSHConnection:
     def makedirs(self, path):
         self._sftp_connect()
 
-        if self.isdir(path):
+        # Single stat call will say whether this is a dir, a file or a link
+        st_mode = self.st_mode(path)
+
+        if stat.S_ISDIR(st_mode):
             return
 
-        if self.isfile(path) or self.islink(path):
+        if stat.S_ISREG(st_mode) or stat.S_ISLNK(st_mode):
             raise DvcException(
                 "a file with the same name '{}' already exists".format(path)
             )
@@ -110,7 +114,13 @@ class SSHConnection:
             self.makedirs(head)
 
         if tail:
-            self._sftp.mkdir(path)
+            try:
+                self._sftp.mkdir(path)
+            except IOError as e:
+                # Since paramiko errors are very vague we need to recheck
+                # whether it's because path already exists or something else
+                if e.errno == errno.EACCES or not self.exists(path):
+                    raise
 
     def walk(self, directory, topdown=True):
         # NOTE: original os.walk() implementation [1] with default options was