Support abstract storage for timestamp metadata

This was erroneously absent in PR 1024, which added support for abstract
files and directories. Resolve by adding a storage_backend argument to
generate_timestamp_metadata() and using it so that the fileinfo (hashes
and length) for the snapshot file can be generated for a snapshot
metadata file on any supported storage.

Signed-off-by: Joshua Lock <[email protected]>

Author: joshuagl

tests/test_repository_lib.py

@@ -512,6 +512,7 @@ def test_generate_timestamp_metadata(self):
     version = 1
     expiration_date = '1985-10-21T13:20:00Z'
 
+    storage_backend = securesystemslib.storage.FilesystemBackend()
     # Load a valid repository so that top-level roles exist in roledb and
     # generate_snapshot_metadata() has roles to specify in snapshot metadata.
     repository = repo_tool.Repository(repository_directory, metadata_directory,
@@ -521,20 +522,20 @@ def test_generate_timestamp_metadata(self):
         repository_name)
 
     timestamp_metadata = repo_lib.generate_timestamp_metadata(snapshot_filename,
-        version, expiration_date, repository_name)
+        version, expiration_date, storage_backend, repository_name)
     self.assertTrue(tuf.formats.TIMESTAMP_SCHEMA.matches(timestamp_metadata))
 
 
     # Test improperly formatted arguments.
     self.assertRaises(securesystemslib.exceptions.FormatError,
         repo_lib.generate_timestamp_metadata, 3, version, expiration_date,
-        repository_name)
+        storage_backend, repository_name)
     self.assertRaises(securesystemslib.exceptions.FormatError,
         repo_lib.generate_timestamp_metadata, snapshot_filename, '3',
-        expiration_date, repository_name)
+        expiration_date, storage_backend, repository_name)
     self.assertRaises(securesystemslib.exceptions.FormatError,
         repo_lib.generate_timestamp_metadata, snapshot_filename, version, '3',
-        repository_name)
+        storage_backend, repository_name)
 
 
 

tuf/repository_lib.py

@@ -135,7 +135,7 @@ def _generate_and_write_metadata(rolename, metadata_filename,
   elif rolename == 'timestamp':
     snapshot_filename = filenames['snapshot']
     metadata = generate_timestamp_metadata(snapshot_filename, roleinfo['version'],
-        roleinfo['expires'], repository_name)
+        roleinfo['expires'], storage_backend, repository_name)
 
     _log_warning_if_expires_soon(TIMESTAMP_FILENAME, roleinfo['expires'],
         TIMESTAMP_EXPIRES_WARN_SECONDS)
@@ -1486,7 +1486,7 @@ def generate_snapshot_metadata(metadata_directory, version, expiration_date,
 
 
 def generate_timestamp_metadata(snapshot_filename, version, expiration_date,
-    repository_name):
+    storage_backend, repository_name):
   """
   <Purpose>
     Generate the timestamp metadata object.  The 'snapshot.json' file must
@@ -1506,14 +1506,14 @@ def generate_timestamp_metadata(snapshot_filename, version, expiration_date,
       The expiration date of the metadata file, conformant to
       'securesystemslib.formats.ISO8601_DATETIME_SCHEMA'.
 
-    repository_name:
-      The name of the repository.  If not supplied, 'rolename' is added to the
-      'default' repository.
-
     storage_backend:
       An object which implements
       securesystemslib.storage.StorageBackendInterface.
 
+    repository_name:
+      The name of the repository.  If not supplied, 'rolename' is added to the
+      'default' repository.
+
   <Exceptions>
     securesystemslib.exceptions.FormatError, if the generated timestamp metadata
     object cannot be formatted correctly, or one of the arguments is improperly
@@ -1538,7 +1538,7 @@ def generate_timestamp_metadata(snapshot_filename, version, expiration_date,
   # Retrieve the versioninfo of the Snapshot metadata file.
   snapshot_fileinfo = {}
   length, hashes = securesystemslib.util.get_file_details(snapshot_filename,
-      tuf.settings.FILE_HASH_ALGORITHMS)
+      tuf.settings.FILE_HASH_ALGORITHMS, storage_backend)
   snapshot_version = get_metadata_versioninfo('snapshot', repository_name)
   snapshot_fileinfo[SNAPSHOT_FILENAME] = \
     tuf.formats.make_fileinfo(length, hashes, version=snapshot_version['version'])