with Drive() structure

src/main.py

@@ -1,6 +1,7 @@
 from datetime import datetime
 import subprocess
 import requests
+import sys
 import os
 
 import config
@@ -9,9 +10,19 @@ def log(*args, **kwargs):
     date = datetime.now().strftime('%d-%b-%Y %H:%M:%S')
     print(f"[{date}]", *args, **kwargs)
 
+def log_error(*args, **kwargs):
+    date = datetime.now().strftime('%d-%b-%Y %H:%M:%S')
+    print(f"[{date}]", *args, **kwargs, file=sys.stderr)
+
+def check_return_code(ret, *args, **kwargs):
+    if ret != 0:
+        log_error(*args, **kwargs)
+        exit(1)
+
 
 if not os.path.exists(config.DISK):
     log_error(f"Drive {config.DISK} not present on the system")
+    exit(1)
 
 passwd = requests.get(config.PWD_URL).text.strip()
 log("Got password :", passwd)
@@ -20,61 +31,77 @@ ssh_key_passwd = requests.get(config.SSH_KEY_PWD_URL).text.strip()
 log("Got password :", ssh_key_passwd)
 
 
-subprocess.run([
-    "cryptsetup", "luksOpen",
-    config.DISK, "backup"
-], input=passwd, text=True)
+class Drive():
+    def __init__(self, disk, passwd, mount_location):
+        self.disk = disk
+        self.passwd = passwd
+        self.mount_location = mount_location
 
-subprocess.call([
-    "mount", "/dev/mapper/backup",
-    config.MNT_LOCATION
-])
+    def __enter__(self):
+        subprocess.run([
+            "cryptsetup", "luksOpen",
+            self.disk, "backup"
+        ], input=self.passwd, text=True)
 
-log("Successfully mounted, doing the backup stuff")
+        subprocess.call([
+            "mount", "/dev/mapper/backup",
+            self.mount_location
+        ])
+        return self
 
-os.makedirs(
-    os.path.join(config.MNT_LOCATION, "latest"),
-    exist_ok=True
-)
+    def __exit__(self, exception_type, exception_value, exception_traceback):
+        subprocess.call([
+            "umount", self.mount_location
+        ])
 
-for src, dest in config.BACKUP_MAP:
-    # We could also use a rsync daemon on the remote machine for pwd(-less) auth
-    subprocess.call(
-        [
-            "sshpass", "-P", "passphrase", "-e",
-                "rsync",
-                "-ahz",
-                "--partial",
-                "--delete",
-                "--stats",
-                f"{config.REMOTE_USER}@{config.REMOTE_LOCATION}:{src}",
-                os.path.join(config.MNT_LOCATION, "latest", dest),
-        ],
-        env={**os.environ, "SSHPASS":ssh_key_passwd}
+        subprocess.call([
+            "cryptsetup", "luksClose",
+            "/dev/mapper/backup"
+        ])
+
+
+with Drive(config.DISK, passwd, config.MNT_LOCATION) as backup_drive:
+    log("Successfully mounted, doing the backup stuff")
+
+    os.makedirs(
+        os.path.join(config.MNT_LOCATION, "latest"),
+        exist_ok=True
     )
 
-log("Rsync ok. Creating snapshot.")
+    for src, dest in config.BACKUP_MAP:
+        # We could also use a rsync daemon on the remote machine for pwd(-less) auth
+        ret = subprocess.call(
+            [
+                "sshpass", "-P", "passphrase", "-e",
+                    "rsync",
+                    "-ahz",
+                    "--partial",
+                    "--delete",
+                    "--stats",
+                    f"{config.REMOTE_USER}@{config.REMOTE_LOCATION}:{src}",
+                    os.path.join(config.MNT_LOCATION, "latest", dest),
+            ],
+            env={**os.environ, "SSHPASS":ssh_key_passwd}
+        )
+        check_return_code(ret, f"Error when syncing {config.REMOTE_LOCATION}")
 
-subprocess.call([
-    "cp", "-a",
-    "--reflink=always", #! The partition must be Btrfs or XFS
-    os.path.join(config.MNT_LOCATION, "latest"),
-    os.path.join(config.MNT_LOCATION, datetime.today().strftime('%Y-%m-%d'))
-])
+    log("Rsync ok. Creating snapshot.")
 
-log("Snapshot ok. Deleting unneeded backups.")
+    ret = subprocess.call([
+        "cp", "-a",
+        "--reflink=always", #! The partition must be Btrfs or XFS
+        os.path.join(config.MNT_LOCATION, "latest"),
+        os.path.join(config.MNT_LOCATION, datetime.today().strftime('%Y-%m-%d'))
+    ])
+    check_return_code(ret, f"Error when creating snapshot")
 
-#TODO
+    log("Snapshot ok. Deleting unneeded backups.")
 
-log("Unmounting.")
+    #TODO
 
-subprocess.call([
-    "umount", config.MNT_LOCATION
-])
+    log("Unmounting.")
 
-subprocess.call([
-    "cryptsetup", "luksClose",
-    "/dev/mapper/backup"
-])
+log("Everything okay, done !")
 
-log("Done !")
+with open("latest-success", "w") as f:
+    f.write(datetime.today().strftime('%Y-%m-%d'))