From 746680731e86fc4e69759332456d4f46d6eef981 Mon Sep 17 00:00:00 2001
From: Fabian <fabian@fh2.ch>
Date: Sun, 1 Mar 2020 00:26:08 +0000
Subject: [PATCH] Add timed backup

---
 host/montalin.nix |  5 ++--
 role/backup.nix   | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)
 create mode 100644 role/backup.nix

diff --git a/host/montalin.nix b/host/montalin.nix
index bdc354b..262a392 100644
--- a/host/montalin.nix
+++ b/host/montalin.nix
@@ -11,6 +11,7 @@
       ../hardware/nuc.nix
       ../role/base.nix
       ../role/dropbear.nix
+      (import ../role/backup.nix {systemdMount = "var-backup.mount"; borgArchiveFolder = "/var/backup/montalin";})
     ];
 
   boot.tmpOnTmpfs = true;
@@ -21,8 +22,8 @@
   };
 
   fileSystems = {
-    "/" = { device = "/dev/mapper/root"; fsType = "btrfs"; };
-    "/var/backup" = { device = "/dev/mapper/backup"; fsType = "ext4"; };
+    "/" = { device = "/dev/mapper/root"; fsType = "btrfs";  options = [ "defaults" "noatime" ]; };
+    "/var/backup" = { device = "/dev/mapper/backup"; fsType = "ext4"; options = [ "defaults" "noauto" "noatime" ]; };
     "/boot" = { device = "/dev/disk/by-uuid/0065-E4EA"; fsType = "vfat"; options = [ "defaults" "noatime" ]; };
   };
 
diff --git a/role/backup.nix b/role/backup.nix
new file mode 100644
index 0000000..e019b7e
--- /dev/null
+++ b/role/backup.nix
@@ -0,0 +1,66 @@
+{
+ systemdMount,
+ borgArchiveFolder,
+ keepWithin? "14d",
+ keepWeekly? "4",
+ keepMonthly? "6",
+ keepYearly? "-1",
+}:
+
+let pkgs = import<nixpkgs>{};
+in
+{
+
+  systemd =  {
+    services.backup = {
+      description = "Backup of all user data and system configuration with BorgBackup";
+      serviceConfig.Type = "oneshot";
+      path = with pkgs; [ bash borgbackup ];
+      script = ''
+        #!/usr/bin/env bash
+        set -euo pipefail
+        IFS=$'\n\t'
+        
+        systemctl start ${systemdMount}
+
+        export BORG_REPO=${borgArchiveFolder} \
+               BORG_BASE_DIR=${borgArchiveFolder}/borg-base-dir
+        
+        echo "Backup started at `date`"
+        borg create --exclude /var/backup \
+                    --exclude /var/tmp \
+                    --exclude /var/cache \
+                    $BORG_REPO::{hostname}-{now} \
+                    /etc \
+                    /home \
+                    /root \
+                    /var
+        
+        sync
+        echo "Backup finished at `date`"
+        
+        echo "Backup prune started at `date`"
+        borg prune --prefix '{hostname}-' \
+                   --keep-within  ${keepWithin} \
+                   --keep-weekly  ${keepWeekly} \
+                   --keep-monthly ${keepMonthly} \
+                   --keep-yearly  ${keepYearly}
+        sync
+        echo "Backup prune finished at `date`"
+
+        systemctl stop ${systemdMount}
+      '';
+    };
+
+    timers.backup = {
+      description = "Backup Schedule";
+
+      timerConfig = {
+        OnCalendar = "13:37";
+        Persistent = "true";
+      };
+
+      wantedBy = [ "timers.target" ];
+    };
+  };
+}