From 3d24d3c5eeb207df8e3481e4ddf8ff19811028d3 Mon Sep 17 00:00:00 2001
From: timeshifter <timeshifter@sumatrae>
Date: Thu, 25 Nov 2021 15:51:38 +0100
Subject: [PATCH] Command --> get_output_of_command()

---
 zfs-backup.py | 57 +++++++++++++++++++++++++--------------------------
 1 file changed, 28 insertions(+), 29 deletions(-)

diff --git a/zfs-backup.py b/zfs-backup.py
index 1355376..5e72f29 100755
--- a/zfs-backup.py
+++ b/zfs-backup.py
@@ -4,6 +4,7 @@
 from __future__ import annotations
 
 import os
+import subprocess
 from subprocess import Popen, PIPE, check_output
 import config
 from sys import exit
@@ -16,21 +17,12 @@ Erstes Backup muss für alle notwendigen Datasets durchgeführt werden mit
 """
 
 
-class Command:
-    def __init__(self, command, strict=True):
-        process = Popen(command, stdout=PIPE)
-        self.stdout, self.stderr = process.communicate()
-        self.exit_code = process.wait()
-        if strict and self.exit_code != 0:
-            raise Exception("Kritisches Kommando fehlgeschlagen. Breche ab.")
-
-
 def find_backup_pool():
     print("Suche nach externer Festplatte für Backups")
-    present_uuids = Command(["ls", "/dev/disk/by-uuid"])
+    present_uuids = get_output_of_command(["ls", "/dev/disk/by-uuid"])
     for key in list(config.backup_pool.keys()):
         uuid = config.backup_pool[key]
-        if uuid in present_uuids.stdout.decode():
+        if uuid in present_uuids:
             print("Gefundene Platte: " + key)
             return key
     else:
@@ -46,27 +38,24 @@ class Dataset:
 
     @classmethod
     def from_local_pool(cls) -> list[Dataset]:
-        datasets_str = (
-            Command([config.ZFS, "list", "-H", "-d", "1", "-o", "name", config.local_pool])
-                .stdout.strip()
-                .decode()
+        datasets_str = get_output_of_command(
+            [config.ZFS, "list", "-H", "-d", "1", "-o", "name", config.local_pool]
         )
         # we omit the first return value, which is the pool, not the dataset
         datasets_list = datasets_str.split("\n")[1:]
         to_backup = [Dataset(d) for d in datasets_list if d not in config.do_not_backup]
-        print("Folgende Datasets und alle darunter befindlichen Kinder werden gesichert:")
+        print(
+            "Folgende Datasets und alle darunter befindlichen Kinder werden gesichert:"
+        )
         for item in to_backup:
             print("  " + str(item))
         return to_backup
 
 
 def get_snapshots(pool):
-    return (
-        Command([config.ZFS, "list", "-r", "-t", "snapshot", "-o", "name", "-H", pool])
-        .stdout.strip()
-        .decode()
-        .split("\n")
-    )
+    return get_output_of_command(
+        [config.ZFS, "list", "-r", "-t", "snapshot", "-o", "name", "-H", pool]
+    ).split()
 
 
 def last_snapshot(pool):
@@ -90,9 +79,9 @@ def last_snapshot(pool):
 def export_pool(pool):
     container_name = "crypt-" + pool
     print("Exportiere Pool " + pool)
-    Command([config.ZPOOL, "export", pool])
+    get_output_of_command([config.ZPOOL, "export", pool])
     print("Schließe verschlüsselten Container")
-    Command([config.CRYPTSETUP, "close", container_name])
+    get_output_of_command([config.CRYPTSETUP, "close", container_name])
     print("Fertig!")
     print("Sie können die externe Festplatte jetzt entfernen.")
 
@@ -100,7 +89,7 @@ def export_pool(pool):
 def import_pool(pool):
     uuid = config.backup_pool[pool]
     container_name = "crypt-" + pool
-    present_mappers = Command(["ls", "/dev/mapper/"]).stdout.decode().strip()
+    present_mappers = get_output_of_command(["ls", "/dev/mapper/"])
     if container_name in present_mappers:
         msg = (
             "verschlüsselter Container "
@@ -109,12 +98,14 @@ def import_pool(pool):
         )
         raise Exception(msg)
     print("Öffne verschlüsselten Container\n")
-    Command([config.CRYPTSETUP, "open", "/dev/disk/by-uuid/" + uuid, container_name])
+    get_output_of_command(
+        [config.CRYPTSETUP, "open", "/dev/disk/by-uuid/" + uuid, container_name]
+    )
     print("")
     print("Importiere Pool " + pool)
     # -N: no mount
     # -d: directory to search the pool in
-    Command([config.ZPOOL, "import", "-N", "-d", "/dev/mapper", pool])
+    get_output_of_command([config.ZPOOL, "import", "-N", "-d", "/dev/mapper", pool])
 
 
 def present_locally(snapshot):
@@ -157,7 +148,9 @@ def do_backup(dataset, last_local_snapshot, last_remote_snapshot, backup_pool):
     # -d  Discard the first element of the sent snapshot's file system name
     # -F  Force a rollback of the file system to the most recent snapshot before performing the receive operation.
     # -u  File system that is associated with the received stream is not mounted.
-    check_output([config.ZFS, "receive", "-d", "-F", "-u", backup_pool], stdin=send.stdout)
+    check_output(
+        [config.ZFS, "receive", "-d", "-F", "-u", backup_pool], stdin=send.stdout
+    )
     exit_code = send.wait()
     if exit_code != 0:
         raise Exception("Kritisches Kommando fehlgeschlagen. Breche ab.")
@@ -195,6 +188,12 @@ def clean_old_snapshots(dataset, pool):
             zfs_destroy(to_delete, recursive=True)
 
 
+def get_output_of_command(cmdline: str | list[str]):
+    if isinstance(cmdline, str):
+        cmdline = [cmdline]
+    return subprocess.check_output(cmdline).strip().decode()
+
+
 def zfs_destroy(full_name, recursive=False):
     if config.local_pool in full_name:
         msg = "Wollte in falschem Pool löschen! Dies sollte niemals passieren! Abbruch!"
@@ -204,7 +203,7 @@ def zfs_destroy(full_name, recursive=False):
         if recursive:
             cmdline.append("-r")
         cmdline.append(full_name)
-        Command(cmdline)
+        get_output_of_command(cmdline)
 
 
 def main():