Move all of NixOS to nixos/ in preparation of the repository merge

nixos/modules/services/databases/mongodb.nix

@@ -0,0 +1,130 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  b2s = x: if x then "true" else "false";
+
+  cfg = config.services.mongodb;
+
+  mongodb = cfg.package;
+
+  mongoCnf = pkgs.writeText "mongodb.conf"
+  ''
+    bind_ip = ${cfg.bind_ip}
+    ${optionalString cfg.quiet "quiet = true"}
+    dbpath = ${cfg.dbpath}
+    logpath = ${cfg.logpath}
+    logappend = ${b2s cfg.logappend}
+    ${optionalString (cfg.replSetName != "") "replSet = ${cfg.replSetName}"}
+  '';
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.mongodb = {
+
+      enable = mkOption {
+        default = false;
+        description = "
+          Whether to enable the MongoDB server.
+        ";
+      };
+
+      package = mkOption {
+        default = pkgs.mongodb;
+        description = "
+          Which MongoDB derivation to use.
+        ";
+      };
+
+      user = mkOption {
+        default = "mongodb";
+        description = "User account under which MongoDB runs";
+      };
+
+      bind_ip = mkOption {
+        default = "127.0.0.1";
+        description = "IP to bind to";
+      };
+
+      quiet = mkOption {
+        default = false;
+        description = "quieter output";
+      };
+
+      dbpath = mkOption {
+        default = "/var/db/mongodb";
+        description = "Location where MongoDB stores its files";
+      };
+
+      logpath = mkOption {
+        default = "/var/log/mongodb/mongod.log";
+        description = "Location where MongoDB stores its logfile";
+      };
+
+      logappend = mkOption {
+        default = true;
+        description = "Append logfile instead over overwriting";
+      };
+
+      replSetName = mkOption {
+        default = "";
+        description = ''
+          If this instance is part of a replica set, set its name here.
+          Otherwise, leave empty to run as single node.
+        '';
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf config.services.mongodb.enable {
+
+    users.extraUsers = singleton
+      { name = cfg.user;
+        description = "MongoDB server user";
+      };
+
+    environment.systemPackages = [ mongodb ];
+
+    systemd.services.mongodb_init =
+      { description = "MongoDB server initialisation";
+
+        wantedBy = [ "mongodb.service" ];
+        before = [ "mongodb.service" ];
+
+        serviceConfig.Type = "oneshot";
+
+        script = ''
+          if ! test -e ${cfg.dbpath}; then
+              install -d -m0700 -o ${cfg.user} ${cfg.dbpath}
+              install -d -m0755 -o ${cfg.user} `dirname ${cfg.logpath}`
+          fi
+        '';
+      };
+
+    systemd.services.mongodb =
+      { description = "MongoDB server";
+
+        wantedBy = [ "multi-user.target" ];
+        after = [ "network.target" ];
+
+        serviceConfig = {
+          ExecStart = "${mongodb}/bin/mongod --quiet --config ${mongoCnf}";
+          User = cfg.user;
+        };
+      };
+
+  };
+
+}