diff --git a/nixos/modules/services/mail/postfixadmin.nix b/nixos/modules/services/mail/postfixadmin.nix
index 7523fa4930ab..0f453d24e52f 100644
--- a/nixos/modules/services/mail/postfixadmin.nix
+++ b/nixos/modules/services/mail/postfixadmin.nix
@@ -1,8 +1,14 @@
-{ lib, config, pkgs, ... }:
+{
+  lib,
+  config,
+  pkgs,
+  ...
+}:
 let
   cfg = config.services.postfixadmin;
   fpm = config.services.phpfpm.pools.postfixadmin;
   localDB = cfg.database.host == "localhost";
+  pgsql = config.services.postgresql;
   user = if localDB then cfg.database.username else "nginx";
 in
 {
@@ -52,6 +58,7 @@ in
           If `database.host` is set to `localhost`, a unix user and group of the same name will be created as well.
         '';
       };
+
       host = lib.mkOption {
         type = lib.types.str;
         default = "localhost";
@@ -62,10 +69,12 @@ in
           permissions.
         '';
       };
+
       passwordFile = lib.mkOption {
         type = lib.types.path;
         description = "Password file for the postgresql connection. Must be readable by user `nginx`.";
       };
+
       dbname = lib.mkOption {
         type = lib.types.str;
         default = "postfixadmin";
@@ -89,7 +98,9 @@ in
       $CONF['database_type'] = 'pgsql';
       $CONF['database_host'] = ${if localDB then "null" else "'${cfg.database.host}'"};
       ${lib.optionalString localDB "$CONF['database_user'] = '${cfg.database.username}';"}
-      $CONF['database_password'] = ${if localDB then "'dummy'" else "file_get_contents('${cfg.database.passwordFile}')"};
+      $CONF['database_password'] = ${
+        if localDB then "'dummy'" else "file_get_contents('${cfg.database.passwordFile}')"
+      };
       $CONF['database_name'] = '${cfg.database.dbname}';
       $CONF['configured'] = true;
 
@@ -126,14 +137,17 @@ in
 
     services.postgresql = lib.mkIf localDB {
       enable = true;
-      ensureUsers = [ {
-        name = cfg.database.username;
-      } ];
+      ensureUsers = [
+        {
+          name = cfg.database.username;
+        }
+      ];
     };
+
     # The postgresql module doesn't currently support concepts like
     # objects owners and extensions; for now we tack on what's needed
     # here.
-    systemd.services.postfixadmin-postgres = let pgsql = config.services.postgresql; in lib.mkIf localDB {
+    systemd.services.postfixadmin-postgres = lib.mkIf localDB {
       after = [ "postgresql.service" ];
       bindsTo = [ "postgresql.service" ];
       wantedBy = [ "multi-user.target" ];
@@ -142,23 +156,23 @@ in
         pkgs.util-linux
       ];
       script = ''
-        set -eu
+        set -euo pipefail
 
         PSQL() {
-            psql --port=${toString pgsql.port} "$@"
+            psql --port=${toString pgsql.settings.port} "$@"
         }
 
         PSQL -tAc "SELECT 1 FROM pg_database WHERE datname = '${cfg.database.dbname}'" | grep -q 1 || PSQL -tAc 'CREATE DATABASE "${cfg.database.dbname}" OWNER "${cfg.database.username}"'
         current_owner=$(PSQL -tAc "SELECT pg_catalog.pg_get_userbyid(datdba) FROM pg_catalog.pg_database WHERE datname = '${cfg.database.dbname}'")
         if [[ "$current_owner" != "${cfg.database.username}" ]]; then
             PSQL -tAc 'ALTER DATABASE "${cfg.database.dbname}" OWNER TO "${cfg.database.username}"'
-            if [[ -e "${config.services.postgresql.dataDir}/.reassigning_${cfg.database.dbname}" ]]; then
+            if [[ -e "${pgsql.dataDir}/.reassigning_${cfg.database.dbname}" ]]; then
                 echo "Reassigning ownership of database ${cfg.database.dbname} to user ${cfg.database.username} failed on last boot. Failing..."
                 exit 1
             fi
-            touch "${config.services.postgresql.dataDir}/.reassigning_${cfg.database.dbname}"
+            touch "${pgsql.dataDir}/.reassigning_${cfg.database.dbname}"
             PSQL "${cfg.database.dbname}" -tAc "REASSIGN OWNED BY \"$current_owner\" TO \"${cfg.database.username}\""
-            rm "${config.services.postgresql.dataDir}/.reassigning_${cfg.database.dbname}"
+            rm "${pgsql.dataDir}/.reassigning_${cfg.database.dbname}"
         fi
       '';
 
@@ -174,7 +188,8 @@ in
       isSystemUser = true;
       createHome = false;
     };
-    users.groups.${user} = lib.mkIf localDB {};
+
+    users.groups.${user} = lib.mkIf localDB { };
 
     services.phpfpm.pools.postfixadmin = {
       user = user;
@@ -183,7 +198,7 @@ in
         error_log = 'stderr'
         log_errors = on
       '';
-      settings = lib.mapAttrs (name: lib.mkDefault) {
+      settings = lib.mapAttrs (_: lib.mkDefault) {
         "listen.owner" = "nginx";
         "listen.group" = "nginx";
         "listen.mode" = "0660";