Add open_backup.sh

Add open_backup, a script to mount the encrypted backup drive created in
arch_backup.

ansible/arch_backup/tasks/main.yml

@@ -18,6 +18,14 @@
     group: root
     mode: '0744'
   become: yes
+- name: Template open_backup.sh
+  ansible.builtin.template:
+    src: open_backup.sh.j2
+    dest: /usr/local/scripts/open_backup.sh
+    owner: root
+    group: root
+    mode: '0744'
+  become: yes
 - name: Ensure hourly backups of each item in backups
   ansible.builtin.cron:
     name: "hourly backup of {{ item }}"

ansible/arch_backup/templates/open_backup.sh.j2

@@ -0,0 +1,47 @@
+# Backup info
+export BACKUP_DRIVE_UUID={{ disk.uuid }}
+export BACKUP_DRIVE_PASSWORD={{ disk.password }}
+export BACKUP_DRIVE_NAME=luks-$BACKUP_DRIVE_UUID
+export BACKUP_DRIVE_MNT=/mnt/$BACKUP_DRIVE_NAME
+
+# For notifications
+export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/{{ notifications.user.uid }}/bus
+export USER={{ notifications.user.name }}
+
+function log {
+    LEVEL=$1
+    MESSAGE=$2
+    echo "$LEVEL: $MESSAGE"
+}
+
+# Unlock backup drive
+if [ -L /dev/disk/by-uuid/$BACKUP_DRIVE_UUID ]; then
+    cryptsetup luksOpen /dev/disk/by-uuid/$BACKUP_DRIVE_UUID $BACKUP_DRIVE_NAME --key-file=$BACKUP_DRIVE_PASSWORD
+    cryptsetup status /dev/mapper/$BACKUP_DRIVE_NAME
+else
+    log "ERROR" "Drive $BACKUP_DRIVE_UUID could not be found."
+    exit 1
+fi
+
+if [ $? = 0 ]; then
+    log "INFO" "Drive $BACKUP_DRIVE_UUID unlocked"
+else
+    log "ERROR" "Drive $BACKUP_DRIVE_UUID could not be unlocked."
+    exit 1
+fi
+
+# Create /mnt/uuid
+log "INFO" "Creating $BACKUP_DRIVE_NAME"
+mkdir -p $BACKUP_DRIVE_MNT
+
+# Mount /mnt/uuid
+log "INFO" "Mounting /dev/mapper/$BACKUP_DRIVE_NAME"
+mount -t btrfs -o compress=zstd /dev/mapper/$BACKUP_DRIVE_NAME $BACKUP_DRIVE_MNT
+
+if [ $? = 0 ]; then
+    log "INFO" "Drive $BACKUP_DRIVE_UUID mounted at $BACKUP_DRIVE_MNT"
+    exit 0
+else
+    log "ERROR" "Drive $BACKUP_DRIVE_NAME could not be mounted."
+    exit 1
+fi