Prevent local storage setup on non-mounted paths

Fixes #269

storage/basestorage.py

@@ -58,6 +58,10 @@ class BaseStorage(StoragePaths):
     """ Called to perform any storage system setup. """
     pass
 
+  def validate(self):
+    """ Called to perform any custom storage system validation. """
+    pass
+
   def get_direct_download_url(self, path, expires_in=60, requires_cors=False):
     return None
 

storage/local.py

@@ -3,6 +3,7 @@ import shutil
 import hashlib
 import io
 import logging
+import psutil
 
 from uuid import uuid4
 
@@ -145,5 +146,20 @@ class LocalStorage(BaseStorageV2):
     else:
       logger.debug('Content already exists at path: %s', final_path_abs)
 
+  def validate(self):
+    # Load the set of disk mounts.
+    try:
+      mounts = psutil.disk_partitions(all=True)
+    except:
+      logger.exception('Could not load disk partitions')
+      return
 
+    # Verify that the storage's root path is under a mounted Docker volume.
+    for mount in mounts:
+      if mount.mountpoint != '/' and self._root_path.startswith(mount.mountpoint):
+        if mount.device == 'tmpfs':
+          return
 
+    raise Exception('Storage path %s is not under a mounted volume.\n\n'
+                    'Registry data must be stored under a mounted volume '
+                    'to prevent data loss' % self._root_path)

util/config/validator.py

@@ -82,7 +82,10 @@ def _validate_registry_storage(config, _):
   """ Validates registry storage. """
   driver = get_storage_provider(config)
 
-  # Put and remove a temporary file.
+  # Run custom validation on the driver.
+  driver.validate()
+
+  # Put and remove a temporary file to make sure the normal storage paths work.
   driver.put_content('_verify', 'testing 123')
   driver.remove('_verify')