Move metadata handling to the Hierarchy class

rbackup/hierarchy/hierarchy.py

@@ -4,6 +4,7 @@
     :synopsis: Classes for creating the backup hierarchy.
 """
 import logging
+import pickle
 
 from pathlib import Path
 
@@ -11,6 +12,11 @@ from pathlib import Path
 syslog = logging.getLogger(__name__)
 
 
+# ========== Constants ==========
+METADATA_READ = "rb"
+METADATA_WRITE = "wb"
+
+
 # ========== Classes ==========
 class Hierarchy:
     """A class for organizing the backup root hierarchy.
@@ -24,6 +30,12 @@ class Hierarchy:
     * path
     * name
     * metadata_path
+
+    Methods
+    -------
+    * read_metadata - read this Hierarchy's metadata from a file
+        and return it
+    * write_metadata - write this Hierarchy's metadata to a file
     """
 
     def __init__(self, dest):
@@ -77,6 +89,20 @@ class Hierarchy:
         """
         return self.path / ".metadata"
 
+    def read_metadata(self):
+        """Read this repository's metadata from its file and
+        then return it.
+
+        :rtype: dict
+        """
+        with self.metadata_path.open(mode=METADATA_READ) as mfile:
+            return pickle.load(mfile)
+
+    def write_metadata(self):
+        """Write this repository's metadata to its file."""
+        with self.metadata_path.open(mode=METADATA_WRITE) as mfile:
+            pickle.dump(self._data, mfile)
+
 
 # ========== Functions ==========
 if __name__ == "__main__":

rbackup/hierarchy/repository.py

@@ -5,7 +5,6 @@
 """
 import logging
 import datetime
-import pickle
 
 from rbackup.hierarchy.hierarchy import Hierarchy
 from rbackup.hierarchy.snapshot import Snapshot
@@ -16,8 +15,6 @@ syslog = logging.getLogger(__name__)
 
 
 # ========== Constants ==========
-METADATA_READ = "rb"
-METADATA_WRITE = "wb"
 DIRMODE = 0o755
 FILEMODE = 0o644
 
@@ -55,7 +52,10 @@ class Repository(Hierarchy):
 
     Methods
     -------
-    * create_snapshot() - create a new snapshot, then update current_snapshot
+    * create_snapshot - create a new snapshot, then update current_snapshot
+    * gen_snapshot_path - generate a path for a snapshot given by name
+    * read_metadata (inherited from Hierarchy)
+    * write_metadata (inherited from Hierarchy)
 
     Directory Structure
     -------------------
@@ -79,25 +79,16 @@ class Repository(Hierarchy):
         self._snapshot_index = 0
 
         if not self.metadata_path.exists():
+            self._data = {"snapshots": [], "current_snapshot": None}
             self._init_new_repository()
         else:
-            self._read_metadata()
+            self._data = self.read_metadata()
 
     def _init_new_repository(self):
         self.metadata_path.parent.mkdir(mode=DIRMODE, exist_ok=True)
         self.metadata_path.touch(mode=FILEMODE)
 
-        self._data = {"snapshots": [], "current_snapshot": None}
+        self.write_metadata()
-
-        self._write_metadata()
-
-    def _read_metadata(self):
-        with self.metadata_path.open(mode=METADATA_READ) as mfile:
-            self._data = pickle.load(mfile)
-
-    def _write_metadata(self):
-        with self.metadata_path.open(mode=METADATA_WRITE) as mfile:
-            pickle.dump(self._data, mfile)
 
     def __len__(self):
         """Return the number of snapshots in this Repository."""
@@ -210,7 +201,12 @@ class Repository(Hierarchy):
         self._data["current_snapshot"] = Snapshot(path)
         self._data["snapshots"].append(self._data["current_snapshot"])
 
-        self._write_metadata()
+        self.write_metadata()
+
+        try:
+            self._data["current_snapshot"].path.mkdir(mode=DIRMODE, parents=True)
+        except FileExistsError as e:
+            raise e
 
         syslog.debug("Snapshot created")
         syslog.debug(f"Snapshot name: {self.current_snapshot.name}")

rbackup/hierarchy/snapshot.py

@@ -24,6 +24,11 @@ class Snapshot(Hierarchy):
     * etc_dir
     * home_dir
     * root_home_dir
+
+    Methods
+    -------
+    * read_metadata (inherited from Hierarchy)
+    * write_metadata (inherited from Hierarchy)
     """
 
     def __init__(self, path):

rbackup/tests/test_repository.py

@@ -29,18 +29,21 @@ class TestRepositoryPreCreate(unittest.TestCase):
         self.patched_path = patch.object(
             Repository, "metadata_path", new_callable=PropertyMock
         )
+        self.patched_r_metadata = patch.object(Repository, "read_metadata")
+        self.patched_w_metadata = patch.object(Repository, "write_metadata")
         self.patched_snapshot = patch(
             f"{TESTING_PACKAGE}.repository.Snapshot", spec_set=Snapshot
         )
-        self.patched_pickle = patch(f"{TESTING_PACKAGE}.repository.pickle")
 
+        self.mocked_r_metadata = self.patched_r_metadata.start()
+        self.mocked_w_metadata = self.patched_w_metadata.start()
         self.mocked_path = self.patched_path.start()
         self.mocked_snapshot = self.patched_snapshot.start()
         self.mocked_pickle = self.patched_pickle.start()
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_empty(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
@@ -53,7 +56,7 @@ class TestRepositoryPreCreate(unittest.TestCase):
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_len(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
@@ -64,15 +67,15 @@ class TestRepositoryPreCreate(unittest.TestCase):
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_current_snapshot(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
 
         if l == []:
-            self.mocked_pickle.load.return_value["current_snapshot"] = None
+            self.mocked_r_metadata.return_value["current_snapshot"] = None
         else:
-            self.mocked_pickle.load.return_value["current_snapshot"] = l[-1]
+            self.mocked_r_metadata.return_value["current_snapshot"] = l[-1]
         repo = Repository("backup")
 
         if l == []:
@@ -83,8 +86,9 @@ class TestRepositoryPreCreate(unittest.TestCase):
 
     def tearDown(self):
         self.patched_path.stop()
+        self.patched_r_metadata.stop()
+        self.patched_w_metadata.stop()
         self.patched_snapshot.stop()
-        self.patched_pickle.stop()
 
 
 class TestRepositoryPostCreate(unittest.TestCase):
@@ -94,26 +98,28 @@ class TestRepositoryPostCreate(unittest.TestCase):
         self.patched_path = patch.object(
             Repository, "metadata_path", new_callable=PropertyMock
         )
+        self.patched_r_metadata = patch.object(Repository, "read_metadata")
+        self.patched_w_metadata = patch.object(Repository, "write_metadata")
         self.patched_snapshot = patch(
             f"{TESTING_PACKAGE}.repository.Snapshot", spec_set=Snapshot
         )
-        self.patched_pickle = patch(f"{TESTING_PACKAGE}.repository.pickle")
 
         self.mocked_path = self.patched_path.start()
+        self.mocked_r_metadata = self.patched_r_metadata.start()
+        self.mocked_w_metadata = self.patched_w_metadata.start()
         self.mocked_snapshot = self.patched_snapshot.start()
-        self.mocked_pickle = self.patched_pickle.start()
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_empty(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
 
         if l == []:
-            self.mocked_pickle.load.return_value["current_snapshot"] = None
+            self.mocked_r_metadata.return_value["current_snapshot"] = None
         else:
-            self.mocked_pickle.load.return_value["current_snapshot"] = l[-1]
+            self.mocked_r_metadata.return_value["current_snapshot"] = l[-1]
         repo = Repository("backup")
 
         repo.create_snapshot()
@@ -122,7 +128,7 @@ class TestRepositoryPostCreate(unittest.TestCase):
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_len(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
@@ -135,7 +141,7 @@ class TestRepositoryPostCreate(unittest.TestCase):
 
     @given(lists(builds(Snapshot, text()), unique=True))
     def test_current_snapshot(self, l):
-        self.mocked_pickle.load.return_value = {
+        self.mocked_r_metadata.return_value = {
             "snapshots": l.copy(),
             "current_snapshot": l[-1] if l else None,
         }
@@ -148,5 +154,6 @@ class TestRepositoryPostCreate(unittest.TestCase):
 
     def tearDown(self):
         self.patched_path.stop()
+        self.patched_r_metadata.stop()
+        self.patched_w_metadata.stop()
         self.patched_snapshot.stop()
-        self.patched_pickle.stop()