lituus up to date

profiles/postgres_upgrade_script/default.nix

@@ -0,0 +1,31 @@
+{ config, pkgs, ... }:
+{
+  environment.systemPackages = [
+    (pkgs.writeScriptBin "upgrade-pg-cluster" ''
+      set -eux
+      # TODO it's perhaps advisable to stop all services that depend on postgresql
+      systemctl stop postgresql
+
+      # TODO replace `<new version>` with the psqlSchema here
+      # The schema can be found by running:
+      # nix-instantiate '<nixpkgs>' --eval -A postgresql_14.psqlSchema
+      export NEWDATA="/var/lib/postgresql/<new version>"
+
+      # TODO specify the postgresql package you'd like to upgrade to
+      export NEWBIN="${pkgs.postgresql_14}/bin"
+
+      export OLDDATA="${config.services.postgresql.dataDir}"
+      export OLDBIN="${config.services.postgresql.package}/bin"
+
+      install -d -m 0700 -o postgres -g postgres "$NEWDATA"
+      cd "$NEWDATA"
+      sudo -u postgres $NEWBIN/initdb -D "$NEWDATA"
+
+      sudo -u postgres $NEWBIN/pg_upgrade \
+        --old-datadir "$OLDDATA" --new-datadir "$NEWDATA" \
+        --old-bindir $OLDBIN --new-bindir $NEWBIN \
+        "$@"
+    '')
+  ];
+}
+