From 4bb0de28c82edb747388a518e5a662b7e17cd666 Mon Sep 17 00:00:00 2001
From: Kevin Veen-Birkenbach <kevin@veen.world>
Date: Wed, 12 Apr 2023 13:37:04 +0200
Subject: [PATCH] implemented backup-pull from static latest instead of
 relative

---
 .../files/pull-remote-backup.sh               | 46 ++++++++++---------
 .../templates/ssh-wrapper.sh.j2               | 20 +++++---
 2 files changed, 38 insertions(+), 28 deletions(-)

diff --git a/roles/native-pull-primary-backups/files/pull-remote-backup.sh b/roles/native-pull-primary-backups/files/pull-remote-backup.sh
index 17f41f3e..e82ef3d8 100644
--- a/roles/native-pull-primary-backups/files/pull-remote-backup.sh
+++ b/roles/native-pull-primary-backups/files/pull-remote-backup.sh
@@ -4,42 +4,46 @@
 # error counter
 errors=0
 
-source_host="backup@$1"
-source_machine_id="$( (ssh "$source_host" sha256sum /etc/machine-id) | head -c 64)" || exit 1
-source_path="/Backups/$source_machine_id/"
-directories="$(ssh "$source_host" find "$source_path" -maxdepth 1 -type d)" || exit 1
+remote_host="backup@$1"
+remote_machine_id="$( (ssh "$remote_host" sha256sum /etc/machine-id) | head -c 64 )" || exit 1
+general_backup_machine_dir="/Backups/$remote_machine_id/"
+remote_backup_types="$(ssh "$remote_host" find "$general_backup_machine_dir" -maxdepth 1 -type d -execdir basename {} ';')" || exit 1
 
-for backup_type_dir in $directories; do
-  if [ "$backup_type_dir" != "$source_path" ]; then
+for backup_type in $remote_backup_types; do
+  if [ "$backup_type" != "$remote_machine_id" ]; then
+    general_backup_type_dir="$general_backup_machine_dir""$backup_type/"
     # folder which contains versions
-    versions_dir="$backup_type_dir/versions/"
+    general_versions_dir="$general_backup_type_dir""versions/"
     # link name of last backup
-    latest_version_link="$backup_type_dir/latest"
+    general_latest_version_link="$general_backup_type_dir""latest"
+    
     # this folder contains the last backup
-    latest_version_dir="$versions_dir$(date '+%Y%m%d%H%M%S')/"
+    local_latest_version_dir="$general_versions_dir$(date '+%Y%m%d%H%M%S')/"
     # this is the link name of the previous version
-    previous_version_link="$backup_type_dir/previous"
-    # source path of the backup files:
-    remote_source_path="$source_host:$latest_version_link/"
+    local_previous_version_link="$general_backup_type_dir""previous"
 
     #identifiy previous version
-    versions=( $(basename -a "$versions_dir"*/ | sort) )|| exit 1
-    last_version="${versions[-1]}" || exit 1
-    previous_version_dir="$versions_dir$last_version/"
+    local_versions=( $(basename -a "$general_versions_dir"*/ | sort) )|| exit 1
+    local_last_version="${local_versions[-1]}" || exit 1
+    local_previous_version_dir="$general_versions_dir""$last_version/"
+
+    # source path of the backup files:
+    remote_last_version_dir="$(readlink -f $general_latest_version_link)"
+    remote_source_path="$remote_host:$remote_last_version_dir/"
 
     # create working folders:
-    mkdir -vp "$latest_version_dir"
+    mkdir -vp "$local_latest_version_dir"
 
     # delete links
-    rm -v "$latest_version_link"
-    rm -v "$previous_version_link"
+    rm -v "$general_latest_version_link"
+    rm -v "$local_previous_version_link"
 
     # create links
-    ln -vs "$latest_version_dir" "$latest_version_link" || exit 1
-    ln -vs "$previous_version_dir" "$previous_version_link"|| exit 1
+    ln -vs "$local_latest_version_dir" "$general_latest_version_link" || exit 1
+    ln -vs "$local_previous_version_dir" "$local_previous_version_link"|| exit 1
 
     # do backup:
-    rsync -abP --delete --delete-excluded --rsync-path="sudo rsync" --link-dest="$previous_version_link" "$remote_source_path" "$latest_version_link" || ((errors+=1));
+    rsync -abP --delete --delete-excluded --rsync-path="sudo rsync" --link-dest="$local_previous_version_link" "$remote_source_path" "$general_latest_version_link" || ((errors+=1));
   fi
 done
 exit $errors;
diff --git a/roles/native-user-backup/templates/ssh-wrapper.sh.j2 b/roles/native-user-backup/templates/ssh-wrapper.sh.j2
index a22b8635..61a1171b 100644
--- a/roles/native-user-backup/templates/ssh-wrapper.sh.j2
+++ b/roles/native-user-backup/templates/ssh-wrapper.sh.j2
@@ -7,17 +7,23 @@ then
 fi
 
 # define executable commands
-hashed_machine_id_command="sha256sum /etc/machine-id";
-find_command="find /Backups/{{hashed_machine_id.stdout}}/ -maxdepth 1 -type d";
-rsync_command="sudo rsync --server --sender -blogDtpre.iLsfxCIvu . /Backups/{{hashed_machine_id.stdout}}/docker-volume-backup/latest/"
+get_hashed_machine_id="sha256sum /etc/machine-id";
+get_backup_types="find /Backups/{{hashed_machine_id.stdout}}/ -maxdepth 1 -type d -execdir basename {} ';'";
+
+# @todo This configuration is not scalable yet. If other backup services then docker-volume-backup are integrated, this logic needs to be optimized
+get_static_last_version_dir="readlink -f /Backups/{{hashed_machine_id.stdout}}/docker-volume-backup/latest/"
+rsync_command="sudo rsync --server --sender -blogDtpre.iLsfxCIvu . $($get_static_last_version_dir)/"
 
 # filter commands
 case "$SSH_ORIGINAL_COMMAND" in
-	"$hashed_machine_id_command")
-		$hashed_machine_id_command
+	"$get_hashed_machine_id")
+		$get_hashed_machine_id
 		;;
-	"$find_command")
-		$find_command
+	"$get_static_last_version_dir")
+		$get_static_last_version_dir
+		;;
+	"$get_backup_types")
+		$get_backup_types
 		;;
 	"$rsync_command")
 		$rsync_command