nixos: add neo4j database module

nixos/modules/misc/ids.nix

@@ -143,6 +143,7 @@
       dhcpd = 133;
       siproxd = 134;
       mlmmj = 135;
+      neo4j = 136;
 
       # When adding a uid, make sure it doesn't match an existing gid. And don't use uids above 399!
 

nixos/modules/module-list.nix

@@ -100,6 +100,7 @@
   ./services/databases/monetdb.nix
   ./services/databases/mongodb.nix
   ./services/databases/mysql.nix
+  ./services/databases/neo4j.nix 
   ./services/databases/openldap.nix
   ./services/databases/postgresql.nix
   ./services/databases/redis.nix

nixos/modules/services/databases/neo4j.nix

@@ -0,0 +1,143 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.neo4j;
+
+  serverConfig = pkgs.writeText "neo4j-server.properties" ''
+    org.neo4j.server.database.location=${cfg.dataDir}/data/graph.db
+    org.neo4j.server.webserver.address=${cfg.host}
+    org.neo4j.server.webserver.port=${toString cfg.port}
+    ${optionalString cfg.enableHttps ''
+      org.neo4j.server.webserver.https.enabled=true
+      org.neo4j.server.webserver.https.port=${toString cfg.httpsPort}
+      org.neo4j.server.webserver.https.cert.location=${cfg.cert}
+      org.neo4j.server.webserver.https.key.location=${cfg.key}
+      org.neo4j.server.webserver.https.keystore.location=${cfg.dataDir}/data/keystore
+    ''}
+    org.neo4j.server.webadmin.rrdb.location=${cfg.dataDir}/data/rrd
+    org.neo4j.server.webadmin.data.uri=/db/data/
+    org.neo4j.server.webadmin.management.uri=/db/manage/
+    org.neo4j.server.db.tuning.properties=${pkgs.neo4j}/share/neo4j/conf/neo4j.properties
+    org.neo4j.server.manage.console_engines=shell
+    ${cfg.extraServerConfig}
+  '';
+
+  loggingConfig = pkgs.writeText "logging.properties" cfg.loggingConfig;
+
+  wrapperConfig = pkgs.writeText "neo4j-wrapper.conf" ''
+    wrapper.java.additional=-Dorg.neo4j.server.properties=${serverConfig}
+    wrapper.java.additional=-Djava.util.logging.config.file=${loggingConfig}
+    wrapper.java.additional=-XX:+UseConcMarkSweepGC
+    wrapper.java.additional=-XX:+CMSClassUnloadingEnabled
+    wrapper.pidfile=${cfg.dataDir}/neo4j-server.pid
+    wrapper.name=neo4j
+  '';
+
+in {
+
+  ###### interface
+
+  options.services.neo4j = {
+    enable = mkOption {
+      description = "Whether to enable neo4j.";
+      default = false;
+      type = types.uniq types.bool;
+    };
+
+    host = mkOption {
+      description = "Neo4j listen address.";
+      default = "127.0.0.1";
+      type = types.str;
+    };
+
+    port = mkOption {
+      description = "Neo4j port to listen for HTTP traffic.";
+      default = 7474;
+      type = types.int;
+    };
+
+    enableHttps = mkOption {
+      description = "Enable https for Neo4j.";
+      default = false;
+      type = types.bool;
+    };
+
+    httpsPort = mkOption {
+      description = "Neo4j port to listen for HTTPS traffic.";
+      default = 7473;
+      type = types.int;
+    };
+
+    cert = mkOption {
+      description = "Neo4j https certificate.";
+      default = "${cfg.dataDir}/conf/ssl/neo4j.cert";
+      type = types.path;
+    };
+
+    key = mkOption {
+      description = "Neo4j https certificate key.";
+      default = "${cfg.dataDir}/conf/ssl/neo4j.key";
+      type = types.path;
+    };
+
+    dataDir = mkOption {
+      description = "Neo4j data directory.";
+      default = "/var/lib/neo4j";
+      type = types.path;
+    };
+
+    loggingConfig = mkOption {
+      description = "Neo4j logging configuration.";
+      default = ''
+        handlers=java.util.logging.ConsoleHandler
+        .level=INFO
+        org.neo4j.server.level=INFO
+
+        java.util.logging.ConsoleHandler.level=INFO
+        java.util.logging.ConsoleHandler.formatter=org.neo4j.server.logging.SimpleConsoleFormatter
+        java.util.logging.ConsoleHandler.filter=org.neo4j.server.logging.NeoLogFilter
+      '';
+      type = types.lines;
+    };
+
+    extraServerConfig = mkOption {
+      description = "Extra configuration for neo4j server.";
+      default = "";
+      type = types.lines;
+    };
+
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    systemd.services.neo4j = {
+      description = "Neo4j Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-interfaces.target" ];
+      environment = { NEO4J_INSTANCE = cfg.dataDir; };
+      serviceConfig = {
+        ExecStart = "${pkgs.neo4j}/bin/neo4j console";
+        User = "neo4j";
+        PermissionsStartOnly = true;
+      };
+      preStart = ''
+        mkdir -m 0700 -p ${cfg.dataDir}/{data/graph.db,conf}
+        ln -fs ${wrapperConfig} ${cfg.dataDir}/conf/neo4j-wrapper.conf
+        if [ "$(id -u)" = 0 ]; then chown -R neo4j ${cfg.dataDir}; fi
+      '';
+    };
+
+    environment.systemPackages = [ pkgs.neo4j ];
+
+    users.extraUsers = singleton {
+      name = "neo4j";
+      uid = config.ids.uids.neo4j;
+      description = "Neo4j daemon user";
+      home = cfg.dataDir;
+    };
+  };
+
+}