bins: add upgrade-pg script

bins/default.nix

@@ -1,4 +1,5 @@
 { pkgs
+, config
 , isUnstable
 , ...
 }:
@@ -19,6 +20,10 @@ let
     inherit (pkgs) curl;
   });
   genPatches = pkgs.callPackage ./gen-patches.nix { };
+  upgrade-pg = pkgs.writeScriptBin "upgrade-pg" (import ./upgrade-pg.nix {
+    inherit pkgs;
+    inherit config;
+  });
 in
 {
   environment.systemPackages = with pkgs; [
@@ -29,7 +34,9 @@ in
     tstart
     xclip
     xinStatus
-  ];
+  ] ++ (if config.services.postgresql.enable then
+    [ upgrade-pg ]
+  else [ ]);
   environment.etc = {
     "signify/openbsd-70-base.pub".text =
       builtins.readFile ./pubs/openbsd-70-base.pub;

bins/upgrade-pg.nix

@@ -0,0 +1,35 @@
+{ pkgs, config }:
+let
+  newPostgres = pkgs.postgresql_16;
+in
+''
+  #!${pkgs.yash}/bin/yash
+
+  set -xe
+
+  if [ pgrep postgres ]; then
+    echo "Please exit all postgres services and stop postgres!"
+    systemctl list-dependencies postgresql.service --reverse
+    exit 1;
+  fi
+
+  export NEWDATA="/var/lib/postgresql/${newPostgres.psqlSchema}"
+  export OLDDATA="${config.services.postgresql.dataDir}"
+
+  if [ "$NEWDATA" == "$OLDDATA" ]; then
+    echo "Nothing to upgrade!"
+    exit 1;
+  fi
+  
+  export NEWBIN="${newPostgres}/bin"
+  export OLDBIN="${config.services.postgresql.package}/bin"
+
+  install -d -m 0700 -o postgres -g postgres "$NEWDATA"
+  cd "$NEWDATA"
+
+  su - postgres -c "$NEWBIN/initdb -D $NEWDATA"
+  su - postgres -c "$NEWBIN/pg_upgrade \
+        --old-datadir $OLDDATA --new-datadir $NEWDATA \
+        --old-bindir $OLDBIN --new-bindir $NEWBIN \
+        $@"
+''