uwsgi: add nixos module

nixos/modules/module-list.nix

@@ -340,6 +340,7 @@
   ./services/web-servers/nginx/default.nix
   ./services/web-servers/phpfpm.nix
   ./services/web-servers/tomcat.nix
+  ./services/web-servers/uwsgi.nix
   ./services/web-servers/varnish/default.nix
   ./services/web-servers/winstone.nix
   ./services/web-servers/zope2.nix

nixos/modules/services/web-servers/uwsgi.nix

@@ -0,0 +1,112 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.uwsgi;
+
+  python2Pkgs = pkgs.python2Packages.override {
+    python = pkgs.uwsgi.python2;
+    self = python2Pkgs;
+  };
+
+  python3Pkgs = pkgs.python3Packages.override {
+    python = pkgs.uwsgi.python3;
+    self = python3Pkgs;
+  };
+
+  buildCfg = c: if builtins.typeOf c != "set" then builtins.readFile c else builtins.toJSON {
+    uwsgi =
+      if c.type == "normal"
+        then {
+          pythonpath =
+               (if c ? python2Packages
+                then builtins.map (x: "${x}/${pkgs.uwsgi.python2.sitePackages}") (c.python2Packages python2Pkgs)
+                else [])
+            ++ (if c ? python3Packages
+                then builtins.map (x: "${x}/${pkgs.uwsgi.python3.sitePackages}") (c.python3Packages python3Pkgs)
+                else []);
+          plugins = cfg.plugins;
+        } // removeAttrs c [ "type" "python2Packages" "python3Packages" ]
+      else if c.type == "emperor"
+        then {
+          emperor = if builtins.typeOf c.vassals != "set" then c.vassals
+                    else pkgs.buildEnv {
+                      name = "vassals";
+                      paths = mapAttrsToList (n: c: pkgs.writeTextDir "${n}.json" (buildCfg c)) c.vassals;
+                    };
+        } // removeAttrs c [ "type" "vassals" ]
+      else abort "type should be either 'normal' or 'emperor'";
+  };
+
+  uwsgi = pkgs.uwsgi.override {
+    plugins = cfg.plugins;
+  };
+
+in {
+
+  options = {
+    services.uwsgi = {
+      
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Enable uWSGI";
+      };
+
+      instance = mkOption {
+        type = types.attrs;
+        default = {
+          type = "normal";
+        };
+        example = literalExample ''
+          {
+            type = "emperor";
+            vassals = {
+              moin = {
+                type = "normal";
+                python2Packages = self: with self; [ moinmoin ];
+                socket = "/run/uwsgi.sock";
+              };
+            };
+          }
+        '';
+        description = ''
+          uWSGI configuration. This awaits either a path to file or a set which will be made into one.
+          If given a set, it awaits an attribute <literal>type</literal> which can be either <literal>normal</literal>
+          or <literal>emperor</literal>.
+
+          For <literal>normal</literal> mode you can specify <literal>python2Packages</literal> and
+          <literal>python3Packages</literal> as functions from libraries set into lists of libraries.
+          For <literal>emperor</literal> mode, you should use <literal>vassals</literal> attribute
+          which should be either a set of names and configurations or a path to a directory.
+        '';
+      };
+
+      plugins = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = "Plugins used with uWSGI";
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    systemd.services.uwsgi = {
+      wantedBy = [ "multi-user.target" ];
+      
+      serviceConfig = {
+        Type = "notify";
+        ExecStart = "${uwsgi}/bin/uwsgi --json ${pkgs.writeText "uwsgi.json" (buildCfg cfg.instance)}";
+        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+        ExecStop = "${pkgs.coreutils}/bin/kill -INT $MAINPID";
+        NotifyAccess = "main";
+        KillSignal = "SIGQUIT";
+      };
+
+    };
+  };
+}