Added container spec

app/specs/__init__.py

@@ -1,3 +1,4 @@
 from .spec import Spec
 from .directory import DirectorySpec
 from .volume import VolumeSpec
+from .container import ContainerSpec

app/specs/container.py

@@ -0,0 +1,49 @@
+from .spec import Spec
+from typing import Union
+from pathlib import Path
+from datetime import datetime
+import subprocess
+
+
+class ContainerSpec(Spec):
+    """
+    A spec for backing up via a container.
+    """
+
+    _SKEL = {"container": None, "command": None, "mountpoint": "/from"}
+
+    def __init__(
+        self,
+        name: str,
+        container: str,
+        destination: Union[str, Path],
+        limit: int,
+        command: str,
+        extension: str,
+        mountpoint: str,
+        notify=None,
+    ):
+        super().__init__(name, destination, limit, extension, notify)
+
+        self.container = container
+        self.mountpoint = mountpoint
+        self.command = command
+
+    def backup(self):
+        # Remove excess backups
+        self.remove_backups()
+
+        # Run actual backup command
+        filename = "{}.{}".format(
+            datetime.now().strftime("%Y-%m-%d_%H-%M-%S"), self.extension
+        )
+
+        process = subprocess.run(
+            "docker exec -t '{}' {} > '{}/{}'".format(
+                self.container, self.command, self.destination, filename
+            ),
+            shell=True,
+        )
+
+        if self.notifier:
+            self.notifier.notify("backup", self.name, process.returncode)

app/specs/volume.py

@@ -7,7 +7,7 @@ import subprocess
 
 class VolumeSpec(Spec):
     """
-    A spec for backup up a Docker volume.
+    A spec for backing up a Docker volume.
     """
 
     _SKEL = {