phpfpm service: restructured pool configuration

From @fpletz: Keep poolConfigs option for backwards-compatibility.

The original commit 6b3f5b5a421fe3422e9ef63a3fd690178c36163e was previously
reverted by c7860cae1a4b54f4b54339142472f00f861fa055 but the issues were
resolved.

nixos/modules/module-list.nix

···
   ./services/web-servers/lighttpd/gitweb.nix
   ./services/web-servers/lighttpd/inginious.nix
   ./services/web-servers/nginx/default.nix
-  ./services/web-servers/phpfpm.nix
+  ./services/web-servers/phpfpm/default.nix
   ./services/web-servers/shellinabox.nix
   ./services/web-servers/tomcat.nix
   ./services/web-servers/uwsgi.nix

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

···
 
   pidFile = "${stateDir}/phpfpm.pid";
 
+  mkPool = n: p: ''
+    [${n}]
+    listen = ${p.listen}
+    ${p.extraConfig}
+  '';
+
   cfgFile = pkgs.writeText "phpfpm.conf" ''
     [global]
     pid = ${pidFile}
     error_log = syslog
     daemonize = yes
     ${cfg.extraConfig}
+
+    ${concatStringsSep "\n" (mapAttrsToList mkPool cfg.pools)}
 
     ${concatStringsSep "\n" (mapAttrsToList (n: v: "[${n}]\n${v}") cfg.poolConfigs)}
   '';
···
       };
 
       poolConfigs = mkOption {
-        type = types.attrsOf types.lines;
         default = {};
+        type = types.attrsOf types.lines;
         example = literalExample ''
           { mypool = '''
               listen = /run/phpfpm/mypool
···
           the phpfpm service is disabled.
         '';
       };
+
+      pools = mkOption {
+        type = types.attrsOf (types.submodule (import ./pool-options.nix {
+          inherit lib;
+        }));
+        default = {};
+        description = ''
+          If no pools are defined, the phpfpm service is disabled.
+        '';
+      };
     };
   };
 
-  config = mkIf (cfg.poolConfigs != {}) {
+  config = mkIf (cfg.pools != {}) {
 
     systemd.services.phpfpm = {
       wantedBy = [ "multi-user.target" ];

nixos/modules/services/web-servers/phpfpm/pool-options.nix

···
+{ lib }:
+
+with lib; {
+
+  options = {
+
+    listen = mkOption {
+      type = types.str;
+      example = "/path/to/unix/socket";
+      description = ''
+        The address on which to accept FastCGI requests.
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = types.lines;
+      example = ''
+        user = nobody
+        pm = dynamic
+        pm.max_children = 75
+        pm.start_servers = 10
+        pm.min_spare_servers = 5
+        pm.max_spare_servers = 20
+        pm.max_requests = 500
+      '';
+
+      description = ''
+        Extra lines that go into the pool configuration.
+        See the documentation on <literal>php-fpm.conf</literal> for
+        details on configuration directives.
+      '';
+    };
+  };
+}
+