hainich: init limesurvey

Have I spent entirely too much time on this? Yes!

Featuring:
 - a heavily modified version of the default limesurvey NixOS module
 - limesurvey 4.4 instead of the default limesurvey 3.23
 - lots and lots of weird hacks
 - postgres instead of mysql
 - nginx instead of apache
 - slightly less weird module options (in my opinion)
 - /slightly/ fewer XSS vulnerabilities, I hope (this is still limesurvey)
 - kind of trivial limesurvey updates, unless upstream decides to break
   things again the way they did when jumping from v3 to v4
 - a full copy of limesurvey in /var/lib/limesurvey, since limesurvey v4
   won't run when it can write in its config dir, which is a well-defined
   path if and only if the entire rest of limesurvey is next to it, and
   the `configdir` var is NOT actually set in limesurvey's config file
 - no symlinks. limesurvey sees through these.

hosts/hainich/configuration.nix

@@ -21,6 +21,7 @@
     ./services/workadventure.nix
     ./services/minecraft.nix
     ./services/mattermost.nix
+    ./services/limesurvey.nix
   ];
   boot.loader.grub.enable = true;
   boot.loader.grub.version = 2;

hosts/hainich/services/limesurvey.nix

@@ -0,0 +1,74 @@
+{config, pkgs, lib, ...}:
+
+{
+
+  containers.limesurvey = {
+    autoStart = true;
+    privateNetwork = true;
+    hostAddress = "192.168.100.40";
+    localAddress = "192.168.100.41";
+
+    config = {config, pkgs, lib, ...}: {
+      imports = [ ./../../../modules/limesurvey.nix ];
+
+      services.limesurvey-patched = {
+        enable = true;
+        domain = "localhost";
+
+        config = {
+          name = "LimeSurvey";
+          components = {
+            db = {
+              connectionString = "pgsql:dbname=limesurvey;host=localhost;port=5432;user=limesurvey";
+              username = "limesurvey";
+              tablePrefix = "limesurvey_";
+            };
+            assetManager.basePath = "/var/lib/limesurvey/tmp/assets";
+            urlManager = {
+              urlFormat = "path";
+              showScriptName = false;
+            };
+          };
+          config = {
+            siteadminemail = "info@infra4future.de";
+            defaultlang = "de";
+          };
+        };
+
+        package = pkgs.limesurvey.overrideAttrs (old: rec {
+          version = "4.4.12+210308";
+          src = pkgs.fetchFromGitHub {
+            owner = "LimeSurvey";
+            repo = "LimeSurvey";
+            rev = version;
+            sha256 = "0kjya8if751mh35symzas186ya27nq62adzp2j58agd5ssrb2a8f";
+          };
+          meta.knownVulnerabilities = [];
+        });
+      };
+
+
+      services.postgresql = {
+        enable = true;
+        ensureDatabases = [ "limesurvey" ];
+        ensureUsers = [ {
+          name = "limesurvey";
+          ensurePermissions = { "DATABASE limesurvey" = "ALL PRIVILEGES"; };
+        } ];
+
+        authentication = lib.mkForce ''
+          # Generated file; do not edit!
+          local all all              trust
+          host  limesurvey limesurvey ::1/128      trust
+        '';
+      };
+      networking.firewall.allowedTCPPorts = [ 80 ];
+    };
+  };
+
+  services.nginx.virtualHosts."survey.infra4future.de" = {
+    locations."/".proxyPass = "http://${config.containers.limesurvey.localAddress}";
+    enableACME = true;
+    forceSSL = true;
+  };
+}

modules/limesurvey.nix

@@ -0,0 +1,162 @@
+{ config, lib, pkgs, ... }:
+
+let
+
+  inherit (lib) mkDefault mkEnableOption mkForce mkIf mkMerge mkOption;
+  inherit (lib) literalExample mapAttrs optional optionalString types;
+
+  cfg = config.services.limesurvey-patched;
+  fpm = config.services.phpfpm.pools.limesurvey;
+
+  user = "limesurvey";
+  group = config.services.nginx.group;
+  stateDir = cfg.stateDir;
+
+  pkg = cfg.package;
+
+  configType = with types; oneOf [ (attrsOf configType) str int bool ] // {
+    description = "limesurvey config type (str, int, bool or attribute set thereof)";
+  };
+
+  limesurveyConfig = pkgs.writeText "config.php" ''
+    <?php
+      return json_decode('${builtins.toJSON cfg.config}', true);
+    ?>
+  '';
+in
+{
+  # interface
+
+  options.services.limesurvey-patched = {
+    enable = mkEnableOption "Limesurvey web application.";
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.limesurvey;
+      description = "The Limesurvey package to use";
+    };
+
+    domain = mkOption {
+      type = types.str;
+      default = "";
+      example = "example.org";
+      description = "the domain name of limesurvey";
+    };
+
+    poolConfig = mkOption {
+      type = with types; attrsOf (oneOf [ str int bool ]);
+      default = {
+        "pm" = "dynamic";
+        "pm.max_children" = 32;
+        "pm.start_servers" = 2;
+        "pm.min_spare_servers" = 2;
+        "pm.max_spare_servers" = 4;
+        "pm.max_requests" = 500;
+      };
+      description = ''
+        Options for the LimeSurvey PHP pool. See the documentation on <literal>php-fpm.conf</literal>
+        for details on configuration directives.
+      '';
+    };
+
+    config = mkOption {
+      type = configType;
+      default = {};
+      description = ''
+        LimeSurvey configuration. Refer to
+        <link xlink:href="https://manual.limesurvey.org/Optional_settings"/>
+        for details on supported values.
+      '';
+    };
+
+    stateDir = mkOption {
+      type = types.str;
+      default = "/var/lib/limesurvey";
+      description = ''
+        LimeSurvey keeps its state in here. For a variety of stupid php reasons, it will also keep a complete
+        copy of itself in here.
+      '';
+    };
+  };
+
+  # implementation
+
+  config = mkIf cfg.enable {
+
+    services.limesurvey-patched.config = mapAttrs (name: mkDefault) {
+      runtimePath = "${stateDir}/tmp/runtime";
+      components = {
+        assetManager.basePath = "${stateDir}/tmp/assets";
+        urlManager = {
+          urlFormat = "path";
+          showScriptName = false;
+        };
+      };
+    };
+
+    services.phpfpm.pools.limesurvey = {
+      inherit user group;
+      phpEnv.LIMESURVEY_CONFIG = "/var/lib/limesurvey/config/config.php";
+      settings = {
+        "listen.owner" = config.services.nginx.user;
+        "listen.group" = config.services.nginx.group;
+      } // cfg.poolConfig;
+    };
+
+    services.nginx = {
+      enable = true;
+
+      virtualHosts.${cfg.domain} = {
+        root = stateDir;
+        locations."/".tryFiles = "$uri /index.php?$args";
+
+        locations."~ [^/]\\.php(/|$)".extraConfig = ''
+         fastcgi_split_path_info ^(.+?\.php)(/.*)$;
+         if (!-f $document_root$fastcgi_script_name) {
+           return 404;
+         }
+         fastcgi_pass unix:${fpm.socket};
+         fastcgi_index index.php;
+        '';
+      };
+    };
+
+    systemd.tmpfiles.rules = [
+      "C ${stateDir} 0750 ${user} ${group} - ${pkg}/share/limesurvey"
+      "d ${stateDir}/tmp 0750 ${user} ${group} - -"
+      "d ${stateDir}/tmp/assets 0750 ${user} ${group} - -"
+      "d ${stateDir}/tmp/runtime 0750 ${user} ${group} - -"
+      "d ${stateDir}/tmp/upload 0750 ${user} ${group} - -"
+    ];
+
+    systemd.services.limesurvey-init = {
+      wantedBy = [ "multi-user.target" ];
+      before = [ "phpfpm-limesurvey.service" ];
+      after = [ "postgresql.service" ];
+      environment.LIMESURVEY_CONFIG = "/var/lib/limesurvey/config/config.php";
+      script = ''
+
+        chmod -R +w ${stateDir}
+        mkdir -p ${stateDir}/config
+        cp -f ${limesurveyConfig} ${stateDir}/config/config.php
+
+        # update or install the database as required
+        ${pkgs.php}/bin/php /var/lib/limesurvey/application/commands/console.php updatedb || \
+        ${pkgs.php}/bin/php /var/lib/limesurvey/application/commands/console.php install admin password admin admin@example.com verbose
+      '';
+      serviceConfig = {
+        User = user;
+        Group = group;
+        Type = "oneshot";
+      };
+    };
+
+    #systemd.services.httpd.after = [ "postgresql.service" ];
+    systemd.services.nginx.after = [ "postgresql.service" ];
+
+    users.users.${user} = {
+      group = group;
+      isSystemUser = true;
+    };
+  };
+}