headscale backup: only keep last five backups

1 files changed, 8 insertions, 0 deletions

diff --git a/hosts/sagittarius/headscale.nix b/hosts/sagittarius/headscale.nix
index 9a09590..05c5e5e 100644
--- a/hosts/sagittarius/headscale.nix
+++ b/hosts/sagittarius/headscale.nix
@@ -69,9 +69,17 @@ in
     ];
     enableStrictShellChecks = true;
     script = ''
+      #!/usr/bin/env bash
+      set -euo pipefail
+
       [ ! -d /var/lib/backup/headscale ] && mkdir -p /var/lib/backup/headscale
       TIMESTAMP="$(date +%Y%m%d%H%M%S)"
       tar cvf "/var/lib/backup/headscale/$TIMESTAMP.backup.tar" /var/lib/headscale
+
+      find /var/lib/backup/headscale -type f -name '*.backup.tar' -print0 |
+        sort --zero-terminated --reverse |
+        tail --zero-terminated --lines=+6 |
+        xargs --null --no-run-if-empty rm --
     '';
     postStop = "systemctl start headscale.service";
   };