alerta: move to all-packages.nix and use buildPythonApplication

nixos/modules/services/monitoring/alerta.nix

···
       };
     };
 
-    environment.systemPackages = [ pkgs.python36Packages.alerta ];
+    environment.systemPackages = [ pkgs.alerta ];
 
     users.users.alerta = {
       uid = config.ids.uids.alerta;

pkgs/development/python-modules/alerta/default.nix

···
-{ lib, buildPythonPackage, fetchPypi
-, six, click, requests, requests-hawk, pytz, tabulate, pythonOlder
-}:
-
-buildPythonPackage rec {
-  pname = "alerta";
-  version = "8.4.0";
-
-  src = fetchPypi {
-    inherit pname version;
-    sha256 = "260ff3118e73396104129928217b0f317ac5afdff8221874d8986df22ecf5f34";
-  };
-
-  propagatedBuildInputs = [ six click requests requests-hawk pytz tabulate ];
-
-  doCheck = false;
-
-  postInstall = ''
-    wrapProgram $out/bin/alerta --prefix PYTHONPATH : "$PYTHONPATH"
-  '';
-
-  disabled = pythonOlder "3.5";
-
-  meta = with lib; {
-    homepage = "https://alerta.io";
-    description = "Alerta Monitoring System command-line interface";
-    license = licenses.asl20;
-  };
-}

pkgs/servers/monitoring/alerta/client.nix

···
+{ lib
+, python3
+}:
+
+python3.pkgs.buildPythonApplication rec {
+  pname = "alerta";
+  version = "8.4.0";
+
+  src = python3.pkgs.fetchPypi {
+    inherit pname version;
+    sha256 = "260ff3118e73396104129928217b0f317ac5afdff8221874d8986df22ecf5f34";
+  };
+
+  propagatedBuildInputs = with python3.pkgs; [
+    six click requests requests-hawk pytz tabulate
+  ];
+
+  doCheck = false;
+
+  disabled = python3.pythonOlder "3.6";
+
+  meta = with lib; {
+    homepage = "https://alerta.io";
+    description = "Alerta Monitoring System command-line interface";
+    license = licenses.asl20;
+  };
+}

pkgs/top-level/all-packages.nix

···
 
   adguardhome = callPackage ../servers/adguardhome {};
 
+  alerta = callPackage ../servers/monitoring/alerta/client.nix { };
+
   alerta-server = callPackage ../servers/monitoring/alerta { };
 
   apacheHttpd_2_4 = callPackage ../servers/http/apache-httpd/2.4.nix { };

pkgs/top-level/python-packages.nix

···
 
   alembic = callPackage ../development/python-modules/alembic { };
 
-  alerta = callPackage ../development/python-modules/alerta { };
-
   algebraic-data-types = callPackage ../development/python-modules/algebraic-data-types { };
 
   allpairspy = callPackage ../development/python-modules/allpairspy { };