nixos/nginx: add option typesHashMaxSize

nixos/modules/services/web-servers/nginx/default.nix

@@ -129,12 +129,9 @@ let
   ''));
 
   commonHttpConfig = ''
-      # Load mime types.
+      # Load mime types and configure maximum size of the types hash tables.
       include ${cfg.defaultMimeTypes};
-      # When recommendedOptimisation is disabled nginx fails to start because the mailmap mime.types database
-      # contains 1026 entries and the default is only 1024. Setting to a higher number to remove the need to
-      # overwrite it because nginx does not allow duplicated settings.
-      types_hash_max_size 4096;
+      types_hash_max_size ${toString cfg.typesHashMaxSize};
 
       include ${cfg.package}/conf/fastcgi.conf;
       include ${cfg.package}/conf/uwsgi_params;
@@ -896,6 +893,22 @@ in
           '';
       };
 
+      typesHashMaxSize = mkOption {
+        type = types.ints.positive;
+        default = if cfg.defaultMimeTypes == "${pkgs.mailcap}/etc/nginx/mime.types" then 2688 else 1024;
+        defaultText = literalExpression ''if cfg.defaultMimeTypes == "''${pkgs.mailcap}/etc/nginx/mime.types" then 2688 else 1024'';
+        description = ''
+          Sets the maximum size of the types hash tables.
+
+          When recommendedOptimisation is disabled nginx fails to start because the
+          mailmap mime.types database contains 1026 entries and the default is only
+          1024. Setting to a higher number to remove the need to overwrite it because
+          nginx does not allow duplicated settings.
+
+          It is recommended that the minimum size be used.
+        '';
+      };
+
       proxyCachePath = mkOption {
         type = types.attrsOf (types.submodule ({ ... }: {
           options = {

nixos/tests/nginx.nix

@@ -98,6 +98,11 @@ import ./make-test-python.nix ({ pkgs, ... }: {
 
     wait_for_nginx_on_port(80)
 
+    with subtest("check optimal size of types_hash"):
+        webserver.fail(
+            "journalctl --unit nginx --grep 'could not build optimal types_hash'"
+        )
+
     with subtest("check ETag if serving Nix store paths"):
         old_etag = check_etag()
         webserver.succeed(