Add remote borg backup support (#4804)

Signed-off-by: Tim Diels <tim@diels.me>
Signed-off-by: Simon L. <szaimen@e.mail.de>
Co-authored-by: Simon L. <szaimen@e.mail.de>

Containers/borgbackup/Dockerfile

@@ -11,11 +11,13 @@ RUN set -ex; \
         rsync \
         fuse \
         py3-llfuse \
-        jq
+        jq \
+        openssh-client
 
 VOLUME /root
 
 COPY --chmod=770 *.sh /
+COPY borg_excludes /
 
 ENTRYPOINT ["/start.sh"]
 # hadolint ignore=DL3002

Containers/borgbackup/backupscript.sh

@@ -34,19 +34,23 @@ for volume in "${DEFAULT_VOLUMES[@]}"; do
 done
 
 # Check if target is mountpoint
-if ! mountpoint -q /mnt/borgbackup; then
-    echo "/mnt/borgbackup is not a mountpoint which is not allowed."
+if [ -z "$BORG_REMOTE_REPO" ] && ! mountpoint -q "$MOUNT_DIR"; then
+    echo "$MOUNT_DIR is not a mountpoint which is not allowed."
     exit 1
 fi
 
-# Check if target is empty
-if [ "$BORG_MODE" != backup ] && [ "$BORG_MODE" != test ] && ! [ -f "$BORG_BACKUP_DIRECTORY/config" ]; then
-    echo "The repository is empty. Cannot perform check or restore."
+# Check if repo is uninitialized
+if [ "$BORG_MODE" != backup ] && [ "$BORG_MODE" != test ] && ! borg info > /dev/null; then
+    if [ -n "$BORG_REMOTE_REPO" ]; then
+        echo "The repository is uninitialized or cannot connect to remote. Cannot perform check or restore."
+    else
+        echo "The repository is uninitialized. Cannot perform check or restore."
+    fi
     exit 1
 fi
 
 # Do not continue if this file exists (needed for simple external blocking)
-if [ -f "$BORG_BACKUP_DIRECTORY/aio-lockfile" ]; then
+if [ -z "$BORG_REMOTE_REPO" ] && [ -f "$BORG_BACKUP_DIRECTORY/aio-lockfile" ]; then
     echo "Not continuing because aio-lockfile exists – it seems like a script is externally running which is locking the backup archive."
     echo "If this should not be the case, you can fix this by deleting the 'aio-lockfile' file from the backup archive directory."
     exit 1
@@ -57,6 +61,13 @@ if [ "$BORG_MODE" = backup ] || [ "$BORG_MODE" = restore ]; then
     touch "/nextcloud_aio_volumes/nextcloud_aio_database_dump/backup-is-running"
 fi
 
+if [ -n "$BORG_REMOTE_REPO" ] && ! [ -f "$BORGBACKUP_KEY" ]; then
+    echo "First run, creating borg ssh key"
+    ssh-keygen  -f "$BORGBACKUP_KEY" -N ""
+    echo "You should configure the remote to accept this public key"
+fi
+echo "Your public ssh key for borgbackup is: $(cat "$BORGBACKUP_KEY.pub")"
+
 # Do the backup
 if [ "$BORG_MODE" = backup ]; then
 
@@ -100,15 +111,22 @@ if [ "$BORG_MODE" = backup ]; then
         exit 1
     fi
 
-    # Create backup folder
-    mkdir -p "$BORG_BACKUP_DIRECTORY"
+    if [ -z "$BORG_REMOTE_REPO" ]; then
+        # Create backup folder
+        mkdir -p "$BORG_BACKUP_DIRECTORY"
+    fi
 
-    # Initialize the repository if the target is empty
-    if ! [ -f "$BORG_BACKUP_DIRECTORY/config" ]; then
+    # Initialize the repository if can't get info from target
+    if ! borg info > /dev/null; then
         # Don't initialize if already initialized
         if [ -f "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/borg.config" ]; then
-            echo "No borg config file was found in the targeted directory."
-            echo "This might happen if the targeted directory is located on an external drive and the drive not connected anymore. You should check this."
+            if [ -n "$BORG_REMOTE_REPO" ]; then
+                echo "Borg could not get info from the remote repo."
+                echo "This might be a failure to connect to the remote server. See the above borg info output for details."
+            else
+                echo "Borg could not get info from the targeted directory."
+                echo "This might happen if the targeted directory is located on an external drive and the drive not connected anymore. You should check this."
+            fi
             echo "If you instead want to initialize a new backup repository, you may delete the 'borg.config' file that is stored in the mastercontainer volume manually, which will allow you to initialize a new borg repository in the chosen directory:"
             echo "sudo docker exec nextcloud-aio-mastercontainer rm /mnt/docker-aio-config/data/borg.config"
             exit 1
@@ -116,28 +134,44 @@ if [ "$BORG_MODE" = backup ]; then
 
         echo "Initializing repository..."
         NEW_REPOSITORY=1
-        if ! borg init --debug --encryption=repokey-blake2 "$BORG_BACKUP_DIRECTORY"; then
+        if ! borg init --debug --encryption=repokey-blake2; then
             echo "Could not initialize borg repository."
-            rm -f "$BORG_BACKUP_DIRECTORY/config"
+            if [ -z "$BORG_REMOTE_REPO" ]; then
+                # Originally we checked for presence of the config file instead of calling `borg info`. Likely `borg info`
+                # will error on a partially initialized repo, so this line is probably no longer necessary
+                rm -f "$BORG_BACKUP_DIRECTORY/config"
+            fi
             exit 1
         fi
-        borg config "$BORG_BACKUP_DIRECTORY" additional_free_space 2G
 
-        # Fix too large Borg cache
-        # https://borgbackup.readthedocs.io/en/stable/faq.html#the-borg-cache-eats-way-too-much-disk-space-what-can-i-do
-        BORG_ID="$(borg config "$BORG_BACKUP_DIRECTORY" id)"
-        rm -r "/root/.cache/borg/$BORG_ID/chunks.archive.d"
-        touch "/root/.cache/borg/$BORG_ID/chunks.archive.d"
+        if [ -z "$BORG_REMOTE_REPO" ]; then
+            # borg config only works for local repos; it's up to the remote to ensure the disk isn't full
+            borg config :: additional_free_space 2G
 
-        # Make a backup from the borg config file
-        if ! [ -f "$BORG_BACKUP_DIRECTORY/config" ]; then
-            echo "The borg config file wasn't created. Something is wrong."
+            # Fix too large Borg cache
+            # https://borgbackup.readthedocs.io/en/stable/faq.html#the-borg-cache-eats-way-too-much-disk-space-what-can-i-do
+            BORG_ID="$(borg config :: id)"
+            rm -r "/root/.cache/borg/$BORG_ID/chunks.archive.d"
+            touch "/root/.cache/borg/$BORG_ID/chunks.archive.d"
+        fi
+
+        if ! borg info > /dev/null; then
+            echo "Borg can't get info from the repo it created. Something is wrong."
             exit 1
         fi
+
         rm -f "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/borg.config"
-        if ! cp "$BORG_BACKUP_DIRECTORY/config" "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/borg.config"; then
-            echo "Could not copy config file to second place. Cannot perform backup."
-            exit 1
+        if [ -n "$BORG_REMOTE_REPO" ]; then
+            # `borg config` does not support remote repos so instead create a dummy file and rely on the remote to avoid
+            # corruption of the config file (which contains the encryption key). We don't actually use the contents of
+            # this file anywhere, so a touch is all we need so we remember we already initialized the repo.
+            touch "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/borg.config"
+        else
+            # Make a backup from the borg config file
+            if ! cp "$BORG_BACKUP_DIRECTORY/config" "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/borg.config"; then
+                echo "Could not copy config file to second place. Cannot perform backup."
+                exit 1
+            fi
         fi
 
         echo "Repository successfully initialized."
@@ -167,9 +201,9 @@ if [ "$BORG_MODE" = backup ]; then
     # Create the backup
     echo "Starting the backup..."
     get_start_time
-    if ! borg create "${BORG_OPTS[@]}" "${BORG_EXCLUDE[@]}" "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-nextcloud-aio" "/nextcloud_aio_volumes/"; then
+    if ! borg create "${BORG_OPTS[@]}" "${BORG_EXCLUDE[@]}" "::$CURRENT_DATE-nextcloud-aio" "/nextcloud_aio_volumes/" --exclude-from /borg_excludes; then
         echo "Deleting the failed backup archive..."
-        borg delete --stats "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-nextcloud-aio"
+        borg delete --stats "::$CURRENT_DATE-nextcloud-aio"
         echo "Backup failed!"
         echo "You might want to check the backup integrity via the AIO interface."
         if [ "$NEW_REPOSITORY" = 1 ]; then
@@ -188,14 +222,14 @@ if [ "$BORG_MODE" = backup ]; then
 
     # Prune archives
     echo "Pruning the archives..."
-    if ! borg prune --stats --glob-archives '*_*-nextcloud-aio' "${BORG_PRUNE_OPTS[@]}" "$BORG_BACKUP_DIRECTORY"; then
+    if ! borg prune --stats --glob-archives '*_*-nextcloud-aio' "${BORG_PRUNE_OPTS[@]}"; then
         echo "Failed to prune archives!"
         exit 1
     fi
 
     # Compact archives
     echo "Compacting the archives..."
-    if ! borg compact "$BORG_BACKUP_DIRECTORY"; then
+    if ! borg compact; then
         echo "Failed to compact archives!"
         exit 1
     fi
@@ -212,19 +246,19 @@ if [ "$BORG_MODE" = backup ]; then
                 fi
             done
             echo "Starting the backup for additional volumes..."
-            if ! borg create "${BORG_OPTS[@]}" "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-additional-docker-volumes" "/docker_volumes/"; then
+            if ! borg create "${BORG_OPTS[@]}" "::$CURRENT_DATE-additional-docker-volumes" "/docker_volumes/"; then
                 echo "Deleting the failed backup archive..."
-                borg delete --stats "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-additional-docker-volumes"
+                borg delete --stats "::$CURRENT_DATE-additional-docker-volumes"
                 echo "Backup of additional docker-volumes failed!"
                 exit 1
             fi
             echo "Pruning additional volumes..."
-            if ! borg prune --stats --glob-archives '*_*-additional-docker-volumes' "${BORG_PRUNE_OPTS[@]}" "$BORG_BACKUP_DIRECTORY"; then
+            if ! borg prune --stats --glob-archives '*_*-additional-docker-volumes' "${BORG_PRUNE_OPTS[@]}"; then
                 echo "Failed to prune additional docker-volumes archives!"
                 exit 1
             fi
             echo "Compacting additional volumes..."
-            if ! borg compact "$BORG_BACKUP_DIRECTORY"; then
+            if ! borg compact; then
                 echo "Failed to compact additional docker-volume archives!"
                 exit 1
             fi
@@ -242,19 +276,19 @@ if [ "$BORG_MODE" = backup ]; then
                 EXCLUDE_DIRS+=(--exclude "/host_mounts/$directory/")
             done
             echo "Starting the backup for additional host mounts..."
-            if ! borg create "${BORG_OPTS[@]}" "${EXCLUDE_DIRS[@]}" "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-additional-host-mounts" "/host_mounts/"; then
+            if ! borg create "${BORG_OPTS[@]}" "${EXCLUDE_DIRS[@]}" "::$CURRENT_DATE-additional-host-mounts" "/host_mounts/"; then
                 echo "Deleting the failed backup archive..."
-                borg delete --stats "$BORG_BACKUP_DIRECTORY::$CURRENT_DATE-additional-host-mounts"
+                borg delete --stats "::$CURRENT_DATE-additional-host-mounts"
                 echo "Backup of additional host-mounts failed!"
                 exit 1
             fi
             echo "Pruning additional host mounts..."
-            if ! borg prune --stats --glob-archives '*_*-additional-host-mounts' "${BORG_PRUNE_OPTS[@]}" "$BORG_BACKUP_DIRECTORY"; then
+            if ! borg prune --stats --glob-archives '*_*-additional-host-mounts' "${BORG_PRUNE_OPTS[@]}"; then
                 echo "Failed to prune additional host-mount archives!"
                 exit 1
             fi
             echo "Compacting additional host mounts..."
-            if ! borg compact "$BORG_BACKUP_DIRECTORY"; then
+            if ! borg compact; then
                 echo "Failed to compact additional host-mount archives!"
                 exit 1
             fi
@@ -276,18 +310,13 @@ fi
 if [ "$BORG_MODE" = restore ]; then
     get_start_time
 
-    # Perform the restore
+    # Pick archive to restore
     if [ -n "$SELECTED_RESTORE_TIME" ]; then
-        SELECTED_ARCHIVE="$(borg list "$BORG_BACKUP_DIRECTORY" | grep "nextcloud-aio" | grep "$SELECTED_RESTORE_TIME" | awk -F " " '{print $1}' | head -1)"
+        SELECTED_ARCHIVE="$(borg list | grep "nextcloud-aio" | grep "$SELECTED_RESTORE_TIME" | awk -F " " '{print $1}' | head -1)"
     else
-        SELECTED_ARCHIVE="$(borg list "$BORG_BACKUP_DIRECTORY" | grep "nextcloud-aio" | awk -F " " '{print $1}' | sort -r | head -1)"
+        SELECTED_ARCHIVE="$(borg list | grep "nextcloud-aio" | awk -F " " '{print $1}' | sort -r | head -1)"
     fi
     echo "Restoring '$SELECTED_ARCHIVE'..."
-    mkdir -p /tmp/borg
-    if ! borg mount "$BORG_BACKUP_DIRECTORY::$SELECTED_ARCHIVE" /tmp/borg; then
-        echo "Could not mount the backup!"
-        exit 1
-    fi
 
     # Save Additional Backup dirs
     if [ -f "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/additional_backup_directories" ]; then
@@ -299,27 +328,12 @@ if [ "$BORG_MODE" = restore ]; then
         DAILY_BACKUPTIME="$(cat /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/daily_backup_time)"
     fi
 
-    # Restore everything except the configuration file
-    if ! rsync --stats --archive --human-readable -vv --delete \
-    --exclude "nextcloud_aio_apache/caddy/**" \
-    --exclude "nextcloud_aio_mastercontainer/caddy/**" \
-    --exclude "nextcloud_aio_nextcloud/data/nextcloud.log*" \
-    --exclude "nextcloud_aio_nextcloud/data/audit.log" \
-    --exclude "nextcloud_aio_mastercontainer/certs/**" \
-    --exclude "nextcloud_aio_mastercontainer/data/configuration.json" \
-    --exclude "nextcloud_aio_mastercontainer/data/daily_backup_running" \
-    --exclude "nextcloud_aio_mastercontainer/data/session_date_file" \
-    --exclude "nextcloud_aio_mastercontainer/session/**" \
-    /tmp/borg/nextcloud_aio_volumes/ /nextcloud_aio_volumes/; then
-        RESTORE_FAILED=1
-        echo "Something failed while restoring from backup."
-    fi
-
     # Save current aio password
     AIO_PASSWORD="$(jq '.password' /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
 
-    # Save current path
+    # Save current backup location vars
     BORG_LOCATION="$(jq '.borg_backup_host_location' /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
+    REMOTE_REPO="$(jq '.borg_remote_repo' /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
 
     # Save current nextcloud datadir
     if grep -q '"nextcloud_datadir":' /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json; then
@@ -328,21 +342,111 @@ if [ "$BORG_MODE" = restore ]; then
         NEXTCLOUD_DATADIR='""'
     fi
 
-    # Restore the configuration file
-    if ! rsync --archive --human-readable -vv \
-    /tmp/borg/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json \
-    /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json; then
-        RESTORE_FAILED=1
-        echo "Something failed while restoring the configuration.json."
+    if [ -z "$BORG_REMOTE_REPO" ]; then
+        mkdir -p /tmp/borg
+        if ! borg mount "::$SELECTED_ARCHIVE" /tmp/borg; then
+            echo "Could not mount the backup!"
+            exit 1
+        fi
+
+        # Restore everything except the configuration file
+        #
+        # These exclude patterns need to be kept in sync with the borg_excludes file and the find excludes in this file,
+        # which use a different syntax (patterns appear in 3 places in total)
+        if ! rsync --stats --archive --human-readable -vv --delete \
+        --exclude "nextcloud_aio_apache/caddy/**" \
+        --exclude "nextcloud_aio_mastercontainer/caddy/**" \
+        --exclude "nextcloud_aio_nextcloud/data/nextcloud.log*" \
+        --exclude "nextcloud_aio_nextcloud/data/audit.log" \
+        --exclude "nextcloud_aio_mastercontainer/certs/**" \
+        --exclude "nextcloud_aio_mastercontainer/data/configuration.json" \
+        --exclude "nextcloud_aio_mastercontainer/data/daily_backup_running" \
+        --exclude "nextcloud_aio_mastercontainer/data/session_date_file" \
+        --exclude "nextcloud_aio_mastercontainer/session/**" \
+        /tmp/borg/nextcloud_aio_volumes/ /nextcloud_aio_volumes/; then
+            RESTORE_FAILED=1
+            echo "Something failed while restoring from backup."
+        fi
+
+        # Restore the configuration file
+        if ! rsync --archive --human-readable -vv \
+                /tmp/borg/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json \
+                /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json; then
+            RESTORE_FAILED=1
+            echo "Something failed while restoring the configuration.json."
+        fi
+
+        if ! umount /tmp/borg; then
+            echo "Failed to unmount the borg archive but should still be able to restore successfully"
+        fi
+    else
+        # Restore nearly everything
+        #
+        # borg mount is really slow for remote repos (did not check whether it's slow for local repos too),
+        # using extract to /tmp would require temporarily storing a second copy of the data.
+        # So instead extract directly on top of the destination with exclude patterns for the config, but
+        # then we do still need to delete local files which are not present in the archive.
+        #
+        # Older backups may still contain files we've since excluded, so we have to exclude on extract as well.
+        cd /  # borg extract has no destination arg and extracts to CWD
+        if ! borg extract "::$SELECTED_ARCHIVE" --progress --exclude-from /borg_excludes --pattern '+nextcloud_aio_volumes/**'
+        then
+            RESTORE_FAILED=1
+            echo "Failed to extract backup archive."
+        else
+            # Delete files/dirs present locally, but not in the backup archive, excluding conf files
+            # https://unix.stackexchange.com/a/759341
+            # This comm does not support -z, but I doubt any file names would have \n in them
+            echo "Deleting local files which do not exist in the backup"
+            # These find patterns need to be kept in sync with the borg_excludes file and the rsync excludes in this
+            # file, which use a different syntax (patterns appear in 3 places in total)
+            if ! find nextcloud_aio_volumes \
+                    -not \( \
+                        -path nextcloud_aio_volumes/nextcloud_aio_apache/caddy \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_apache/caddy/*" \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_mastercontainer/caddy \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_mastercontainer/caddy/*" \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_mastercontainer/certs \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_mastercontainer/certs/*" \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_mastercontainer/session \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_mastercontainer/session/*" \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_nextcloud/data/nextcloud.log*" \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_nextcloud/data/audit.log \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/daily_backup_running \
+                        -o -path nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/session_date_file \
+                        -o -path "nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/id_borg*" \
+                    \) \
+                    | LC_ALL=C sort \
+                    | LC_ALL=C comm -23 - \
+                        <(borg list "::$SELECTED_ARCHIVE" --short --exclude-from /borg_excludes  --pattern '+nextcloud_aio_volumes/**' | LC_ALL=C sort) \
+                    > /tmp/local_files_not_in_backup
+            then
+                RESTORE_FAILED=1
+                echo "Failed to delete local files not in backup archive."
+            else
+                # More robust than e.g. xargs as I got a ~"args line too long" error while testing that, but it's slower
+                # https://stackoverflow.com/a/21848934
+                while IFS= read -r file
+                do rm -vrf -- "$file" || DELETE_FAILED=1
+                done < /tmp/local_files_not_in_backup
+
+                if [ "$DELETE_FAILED" = 1 ]; then
+                    RESTORE_FAILED=1
+                    echo "Failed to delete (some) local files not in backup archive."
+                fi
+            fi
+        fi
     fi
 
     # Set backup-mode to restore since it was a restore
     CONTENTS="$(jq '."backup-mode" = "restore"' /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
     echo -E "${CONTENTS}" > /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json
 
-    # Reset the backup path to the currently used one
+    # Reset the backup location vars to the currently used one
     CONTENTS="$(jq ".borg_backup_host_location = $BORG_LOCATION" /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
     echo -E "${CONTENTS}" > /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json
+    CONTENTS="$(jq ".borg_remote_repo = $REMOTE_REPO" /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
+    echo -E "${CONTENTS}" > /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json
 
     # Reset the AIO password to the currently used one
     CONTENTS="$(jq ".password = $AIO_PASSWORD" /nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/configuration.json)"
@@ -366,8 +470,6 @@ if [ "$BORG_MODE" = restore ]; then
         chmod 770 "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/daily_backup_time"
     fi
 
-    umount /tmp/borg
-
     if [ "$RESTORE_FAILED" = 1 ]; then
         exit 1
     fi
@@ -394,7 +496,7 @@ if [ "$BORG_MODE" = check ]; then
     echo "Checking the backup integrity..."
 
     # Perform the check
-    if ! borg check -v --verify-data "$BORG_BACKUP_DIRECTORY"; then
+    if ! borg check -v --verify-data; then
         echo "Some errors were found while checking the backup integrity!"
         echo "Check the AIO interface for advices on how to proceed now!"
         exit 1
@@ -412,7 +514,7 @@ if [ "$BORG_MODE" = "check-repair" ]; then
     echo "Checking the backup integrity and repairing it..."
 
     # Perform the check-repair
-    if ! echo YES | borg check -v --repair "$BORG_BACKUP_DIRECTORY"; then
+    if ! echo YES | borg check -v --repair; then
         echo "Some errors were found while checking and repairing the backup integrity!"
         exit 1
     fi
@@ -425,19 +527,29 @@ fi
 
 # Do the backup test
 if [ "$BORG_MODE" = test ]; then
-    if ! [ -d "$BORG_BACKUP_DIRECTORY" ]; then
-        echo "No 'borg' directory in the given backup directory found!"
-        echo "Only the files/folders below have been found in the given directory."
-        ls -a "$MOUNT_DIR"
-        echo "Please adjust the directory so that the borg archive is positioned in a folder named 'borg' inside the given directory!"
-        exit 1
-    elif ! [ -f "$BORG_BACKUP_DIRECTORY/config" ]; then
-        echo "A 'borg' directory was found but could not find the borg archive."
-        echo "Only the files/folders below have been found in the borg directory."
-        ls -a "$BORG_BACKUP_DIRECTORY"
-        echo "The archive and most importantly the config file must be positioned directly in the 'borg' subfolder."
-        exit 1
-    elif ! borg list "$BORG_BACKUP_DIRECTORY"; then
+    if [ -n "$BORG_REMOTE_REPO" ]; then
+        if ! borg info > /dev/null; then
+            echo "Borg could not get info from the remote repo."
+            echo "See the above borg info output for details."
+            exit 1
+        fi
+    else
+        if ! [ -d "$BORG_BACKUP_DIRECTORY" ]; then
+            echo "No 'borg' directory in the given backup directory found!"
+            echo "Only the files/folders below have been found in the given directory."
+            ls -a "$MOUNT_DIR"
+            echo "Please adjust the directory so that the borg archive is positioned in a folder named 'borg' inside the given directory!"
+            exit 1
+        elif ! [ -f "$BORG_BACKUP_DIRECTORY/config" ]; then
+            echo "A 'borg' directory was found but could not find the borg archive."
+            echo "Only the files/folders below have been found in the borg directory."
+            ls -a "$BORG_BACKUP_DIRECTORY"
+            echo "The archive and most importantly the config file must be positioned directly in the 'borg' subfolder."
+            exit 1
+        fi
+    fi
+
+    if ! borg list; then
         echo "The entered path seems to be valid but could not open the backup archive."
         echo "Most likely the entered password was wrong so please adjust it accordingly!"
         exit 1

Containers/borgbackup/borg_excludes

@@ -0,0 +1,11 @@
+# These patterns need to be kept in sync with rsync and find excludes in backupscript.sh,
+# which use a different syntax (patterns appear in 3 places in total)
+nextcloud_aio_volumes/nextcloud_aio_apache/caddy/
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/caddy/
+nextcloud_aio_volumes/nextcloud_aio_nextcloud/data/nextcloud.log*
+nextcloud_aio_volumes/nextcloud_aio_nextcloud/data/audit.log
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/certs/
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/daily_backup_running
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/session_date_file
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/session/
+nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/id_borg*

Containers/borgbackup/start.sh

@@ -2,7 +2,7 @@
 
 # Variables
 export MOUNT_DIR="/mnt/borgbackup"
-export BORG_BACKUP_DIRECTORY="$MOUNT_DIR/borg"
+export BORG_BACKUP_DIRECTORY="$MOUNT_DIR/borg"  # necessary even when remote to store the aio-lockfile
 
 # Validate BORG_PASSWORD
 if [ -z "$BORG_PASSWORD" ] && [ -z "$BACKUP_RESTORE_PASSWORD" ]; then
@@ -18,6 +18,18 @@ else
 fi
 export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=yes
 export BORG_RELOCATED_REPO_ACCESS_IS_OK=yes
+if [ -n "$BORG_REMOTE_REPO" ]; then
+    export BORG_REPO="$BORG_REMOTE_REPO"
+
+    # Location to create the borg ssh pub/priv key
+    export BORGBACKUP_KEY="/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/id_borg"
+
+    # Accept any host key the first time connecting to the remote. Strictly speaking should be provided by user but you'd
+    # have to be very unlucky to get MitM'ed on your first connection.
+    export BORG_RSH="ssh -o StrictHostKeyChecking=accept-new -i $BORGBACKUP_KEY"
+else
+    export BORG_REPO="$BORG_BACKUP_DIRECTORY"
+fi
 
 # Validate BORG_MODE
 if [ "$BORG_MODE" != backup ] && [ "$BORG_MODE" != restore ] && [ "$BORG_MODE" != check ] && [ "$BORG_MODE" != "check-repair" ] && [ "$BORG_MODE" != test ]; then
@@ -36,8 +48,8 @@ fi
 rm -f "/nextcloud_aio_volumes/nextcloud_aio_database_dump/backup-is-running"
 
 # Get a list of all available borg archives
-if borg list "$BORG_BACKUP_DIRECTORY" &>/dev/null; then
-    borg list "$BORG_BACKUP_DIRECTORY" | grep "nextcloud-aio" | awk -F " " '{print $1","$3,$4}' > "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/backup_archives.list"
+if borg list &>/dev/null; then
+    borg list | grep "nextcloud-aio" | awk -F " " '{print $1","$3,$4}' > "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/backup_archives.list"
 else
     echo "" > "/nextcloud_aio_volumes/nextcloud_aio_mastercontainer/data/backup_archives.list"
 fi