feature(backup): loading snapshots

selfprivacy_api/backup/restic_backuper.py

@@ -1,4 +1,5 @@
 import subprocess
+import json
 
 from selfprivacy_api.backup.backuper import AbstractBackuper
 
@@ -79,3 +80,42 @@ class ResticBackuper(AbstractBackuper):
         )
 
         subprocess.run(restore_command, shell=False)
+
+    def _load_snapshots(self, repo_name) -> object:
+        """
+        Load list of snapshots from repository
+        """
+        listing_command = self.restic_command(
+            repo_name,
+            "snapshots",
+            "--json",
+        )
+
+        with subprocess.Popen(
+            listing_command,
+            shell=False,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+        ) as backup_listing_process_descriptor:
+            output = backup_listing_process_descriptor.communicate()[0].decode("utf-8")
+
+        try:
+            return self.parse_snapshot_output(output)
+        except ValueError:
+            if "Is there a repository at the following location?" in output:
+                return []
+            self.error_message = output
+            return []
+
+    def get_snapshots(self):
+        # No transformation for now
+        snapshots = []
+        for snapshot in self._load_snapshots():
+            snapshots.append(snapshot)
+        return snapshots
+
+    def parse_snapshot_output(self, output: str) -> object:
+        starting_index = output.find("[")
+        json.loads(output[starting_index:])
+        self.snapshot_list = json.loads(output[starting_index:])
+        print(output)