wip: postgres

We do not want to start multiple borgbackups in parallel

checks/postgres/default.nix

@@ -0,0 +1,17 @@
+(import ../lib/container-test.nix) (
+  { pkgs, ... }:
+  {
+    name = "secrets";
+
+    nodes.machine =
+      { self, ... }:
+      {
+        imports = [ self.clanModules.postgres ];
+      };
+    testScript = ''
+      start_all()
+      machine.wait_for_unit("postgres")
+      machine.succeed("${pkgs.netcat}/bin/nc -z -v ::1 5432")
+    '';
+  }
+)

clanModules/borgbackup.nix

@@ -94,7 +94,7 @@ in
       (pkgs.writeShellScriptBin "borgbackup-create" ''
         set -efu -o pipefail
         ${lib.concatMapStringsSep "\n" (dest: ''
-          systemctl start borgbackup-job-${dest.name}
+          systemctl start --wait borgbackup-job-${dest.name}
         '') (lib.attrValues cfg.destinations)}
       '')
       (pkgs.writeShellScriptBin "borgbackup-list" ''

clanModules/postgresql.nix

@@ -0,0 +1,40 @@
+{
+  lib,
+  config,
+  pkgs,
+  ...
+}:
+{
+  services.postgresql.enable = true;
+  services.postgresqlBackup = {
+    enable = lib.mkDefault true;
+    startAt = lib.mkDefault [ ]; # we will start this as part of the backup
+    compression = "zstd";
+  };
+  clanCore.state.postgres.folders = [ "/var/backup/postgresql" ];
+
+  assertions = [
+    ({
+      assertion = config.postgresqlBackup.databases == [ ];
+      message = "We currently do not support backing up specific databases. Please set postgresqlBackup.databases to an empty list. Or disable services.postgresqlBackup.enable";
+    })
+  ];
+
+  clanCore.state.postgres.postRestoreScript = ''
+    for dump in /var/backup/postgresql/all*; do
+      case "$dump" in
+        *.gz) decompressionCmd="${pkgs.gzip}/bin/gzip -d -${toString config.services.postgresqlBackup.compressionLevel}" ;;
+        *.zst) decompressionCmd="${pkgs.zstd}/bin/zstd -d -${toString config.services.postgresqlBackup.compressionLevel}" ;;
+        *) decompressionCmd="cat" ;;
+      esac
+      $decompressionCmd $dump | psql template1
+      break
+    done
+  '';
+
+  services.borgbackup.jobs.${config.networking.hostName} = {
+    preHook = ''
+      ${pkgs.systemd}/bin/systemctl start postgresqlBackup
+    '';
+  };
+}