[Web][Restic][Dovecot][Dockerapi] Add restic backups with restore in the UI

- Scheduled, encrypted backups to S3, SFTP, REST or a local folder (new restic-mailcow container)
- Restore of mailboxes and whole domains in the UI, also deleted ones, for admins and domain admins
- Scope set by RESTIC_BACKUP_MODE in mailcow.conf (all, data, config)
- Optional backup before updates (update.sh), helper-scripts/restic.sh for a full restore

_modules/scripts/backup.sh

@@ -0,0 +1,71 @@
+#!/usr/bin/env bash
+# _modules/scripts/backup.sh
+# THIS SCRIPT IS DESIGNED TO BE RUNNING BY MAILCOW SCRIPTS ONLY!
+# DO NOT, AGAIN, NOT TRY TO RUN THIS SCRIPT STANDALONE!!!!!!
+
+# Backup with restic before the update when it is set up (target, confirmed password, initialized repository):
+# interactive: asked for; --backup: without asking; --force: none (with --backup: without asking, a failure or a backup
+# that cannot run stops the update; only "not set up" continues)
+backup_failed() {
+  echo -e "\e[31m${1}\e[0m"
+  if [ "$FORCE" ]; then
+    echo "The update was started with --force --backup, it stops here. Nothing was changed."
+    exit 1
+  fi
+  read -r -p "Continue the update without a backup? [y/N] " backup_response
+  if [[ ! "${backup_response}" =~ ^([yY][eE][sS]|[yY])+$ ]]; then
+    echo "OK, exiting."
+    exit 1
+  fi
+}
+
+# Whether to back up (asked with the other questions); the backup itself runs before the first change of the checkout
+backup_decide() {
+  local output rc
+  RUN_BACKUP=
+  if [ "$FORCE" ] && [ ! "$BACKUP" ]; then
+    return 0
+  fi
+  if [[ -z "$($COMPOSE_COMMAND ps -q restic-mailcow 2> /dev/null)" ]]; then
+    output="the backup container does not run"
+    rc=1
+  else
+    # exit code 0: set up, 2: not set up, others: error (e.g. credentials this container cannot read)
+    output=$($COMPOSE_COMMAND exec -T restic-mailcow python3 /usr/local/bin/restic_runner.py --configured 2>&1 < /dev/null)
+    rc=$?
+  fi
+  if [[ ${rc} -eq 2 ]]; then
+    [ "$BACKUP" ] && echo -e "\e[33mNo backup before the update: ${output}.\e[0m"
+    return 0
+  elif [[ ${rc} -ne 0 ]]; then
+    if [ "$BACKUP" ]; then
+      backup_failed "No backup before the update possible: ${output}"
+    elif [[ -n "$($COMPOSE_COMMAND ps -q restic-mailcow 2> /dev/null)" ]]; then
+      echo -e "\e[33mNo backup before the update: ${output}\e[0m"
+    fi
+    return 0
+  fi
+  if [ ! "$BACKUP" ]; then
+    read -r -p "Create a backup before the update? [Y/n] " backup_response
+    if [[ "${backup_response}" =~ ^([nN][oO]|[nN])$ ]]; then
+      echo "OK, no backup."
+      return 0
+    fi
+  fi
+  RUN_BACKUP=y
+}
+
+# The backup chosen by backup_decide, once
+backup_run() {
+  if [ ! "$RUN_BACKUP" ]; then
+    return 0
+  fi
+  RUN_BACKUP=
+  if [[ "${RESTIC_BACKUP_MODE}" =~ ^(data|config)$ ]]; then
+    echo -e "\e[33mRESTIC_BACKUP_MODE=${RESTIC_BACKUP_MODE}: the backup holds no complete mailcow directory, a restore does not bring back this mailcow version.\e[0m"
+  fi
+  echo -e "\e[32mCreating a backup before the update...\e[0m"
+  if ! $COMPOSE_COMMAND exec -T restic-mailcow python3 /usr/local/bin/restic_runner.py --backup < /dev/null; then
+    backup_failed "The backup before the update failed, see the output above and the backup jobs in the mailcow UI."
+  fi
+}