fix backup

system/backup

@@ -1,18 +1,19 @@
 #!/bin/bash
 #
-# Purpose : Back up your home folder with borg to your Nextcloud files, in
-#           /mnt/<domain>/.backup-<hostname>. Run daily by
-#           coredesktop-backup.timer; `configure backup` sets it up.
+# Purpose : Back up your home folder with restic to your Nextcloud files, in
+#           .backup-<hostname>. Run daily by coredesktop-backup.timer;
+#           `configure backup` sets it up.
 #
 # Keeps 7 daily, 4 weekly and 6 monthly backups. To leave out more, list
-# paths or borg patterns in ~/.config/coredesktop/backup-exclude, one per line.
+# paths or patterns in ~/.config/coredesktop/backup-exclude, one per line.
 
 # Wrapped in { ...; exit; } so bash reads the whole script up front; update
 # replaces this file (git pull) while a backup may be running.
 {
 
-BACKUP_CONF="$HOME/.config/coredesktop/backup.conf"
+COREDESKTOP="$HOME/.local/share/coredesktop"
 USER_EXCLUDE="$HOME/.config/coredesktop/backup-exclude"
+LOG_HINT="See: journalctl --user -u coredesktop-backup"
 
 # Tell the desktop when a backup fails, as no one watches the timer
 fail() {
@@ -21,22 +22,17 @@ fail() {
   exit 1
 }
 
-[ -f "$BACKUP_CONF" ] || fail "Backups aren't set up. Run: configure backup"
-source "$BACKUP_CONF"
+source "$COREDESKTOP/system/backup-env.sh" || exit 1
+[ -n "$RESTIC_REPOSITORY" ] || fail "Backups aren't set up. Run: configure backup"
+[ -n "$RESTIC_PASSWORD_COMMAND" ] || fail "The backup's passphrase isn't in your keyring. Run: configure backup"
 
-# The files mount comes up at login, perhaps before the network; give it a
-# few minutes rather than writing into the empty folder underneath
+# Run at login, perhaps before the network is up; give it a few minutes
 for try in {1..10}; do
-  mountpoint -q "$BACKUP_MOUNT" && break
-  mount "$BACKUP_MOUNT" 2> /dev/null && break
+  curl -sf --max-time 10 -o /dev/null "${BACKUP_WEBDAV%%/remote.php/*}/status.php" && break
   sleep 30
 done
-mountpoint -q "$BACKUP_MOUNT" || fail "Your Nextcloud files aren't mounted at $BACKUP_MOUNT."
 
-export BORG_REPO
-export BORG_PASSCOMMAND="secret-tool lookup coredesktop backup repo $BORG_REPO"
-
-# Rebuilt by borg, or by reinstalling, so not worth the space
+# Rebuilt by restic, or by reinstalling, so not worth the space
 excludes=(
   "$HOME/.cache"
   "$HOME/.davfs2/cache"
@@ -52,23 +48,20 @@ excludes=(
 )
 exclude_args=(--exclude-caches)
 for path in "${excludes[@]}"; do
-  exclude_args+=(--exclude "sh:$path")
+  exclude_args+=(--exclude "$path")
 done
-[ -f "$USER_EXCLUDE" ] && exclude_args+=(--exclude-from "$USER_EXCLUDE")
+[ -f "$USER_EXCLUDE" ] && exclude_args+=(--exclude-file "$USER_EXCLUDE")
 
-echo "Backing up $HOME to $BORG_REPO..."
+echo "Backing up $HOME to $BACKUP_DIR in your Nextcloud files..."
 # --one-file-system leaves out other mounts and btrfs subvolumes inside home
-borg create --one-file-system --compression zstd --stats \
-  "${exclude_args[@]}" "::{hostname}-{now:%Y-%m-%dT%H:%M}" "$HOME"
+restic backup --one-file-system --host "$HOSTNAME" "${exclude_args[@]}" "$HOME"
 status=$?
-# 1 is a warning, e.g. a file changed while it was read; the backup still exists
-(( status <= 1 )) || fail "borg couldn't back up $HOME (exit $status). See: journalctl --user -u coredesktop-backup"
+# 3 means some files couldn't be read; the rest were backed up
+(( status == 0 || status == 3 )) || fail "restic couldn't back up $HOME (exit $status). $LOG_HINT"
 
 echo "Removing old backups..."
-borg prune --glob-archives '{hostname}-*' \
-  --keep-daily 7 --keep-weekly 4 --keep-monthly 6 \
-  || fail "borg couldn't remove old backups. See: journalctl --user -u coredesktop-backup"
-borg compact || fail "borg couldn't free space from old backups. See: journalctl --user -u coredesktop-backup"
+restic forget --host "$HOSTNAME" --keep-daily 7 --keep-weekly 4 --keep-monthly 6 --prune \
+  || fail "restic couldn't remove old backups. $LOG_HINT"
 
 echo "Backup finished."
 exit 0

system/backup-env.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+#
+# Purpose : Point restic at your backup in your Nextcloud files. Sourced by
+#           system/backup and configure.d/20-backup.sh, and by you to look at
+#           or restore from a backup:
+#
+#             source ~/.local/share/coredesktop/system/backup-env.sh
+#             restic snapshots
+#
+#           To use another computer's backup, name its folder:
+#
+#             source ~/.local/share/coredesktop/system/backup-env.sh .backup-<name>
+#
+# restic reaches Nextcloud over WebDAV through rclone, not the davfs2 mount,
+# which can't safely replace files. The Nextcloud app password and the
+# backup's passphrase are kept in your keyring.
+
+BACKUP_CONF="$HOME/.config/coredesktop/backup.conf"
+
+# A secret from the keyring: nextcloud (app password) or passphrase
+backup_secret() {
+  secret-tool lookup coredesktop backup item "$1" url "$2"
+}
+
+if [ -f "$BACKUP_CONF" ]; then
+  source "$BACKUP_CONF"
+  BACKUP_DIR="${1:-$BACKUP_DIR}"
+
+  export RCLONE_WEBDAV_URL="$BACKUP_WEBDAV"
+  export RCLONE_WEBDAV_VENDOR=nextcloud
+  export RCLONE_WEBDAV_USER="$BACKUP_USER"
+  RCLONE_WEBDAV_PASS="$(backup_secret nextcloud "$BACKUP_WEBDAV" | rclone obscure -)"
+  export RCLONE_WEBDAV_PASS
+  export RESTIC_REPOSITORY="rclone::webdav:$BACKUP_DIR"
+
+  # Without a passphrase in the keyring, e.g. for another computer's backup,
+  # restic asks for it
+  unset RESTIC_PASSWORD_COMMAND
+  if [ -n "$(backup_secret passphrase "$BACKUP_WEBDAV/$BACKUP_DIR")" ]; then
+    export RESTIC_PASSWORD_COMMAND="secret-tool lookup coredesktop backup item passphrase url $BACKUP_WEBDAV/$BACKUP_DIR"
+  fi
+else
+  echo "Backups aren't set up. Run: configure backup" >&2
+fi