apache-kafka: New service for Apache Kafka

nixos/modules/misc/ids.nix

@@ -176,7 +176,7 @@
       tox-bootstrapd = 166;
       cadvisor = 167;
       nylon = 168;
-
+      apache-kafka = 169;
       # When adding a uid, make sure it doesn't match an existing gid. And don't use uids above 399!
 
       nixbld = 30000; # start of range of uids

nixos/modules/module-list.nix

@@ -170,6 +170,7 @@
   ./services/mail/opensmtpd.nix
   ./services/mail/postfix.nix
   ./services/mail/spamassassin.nix
+  ./services/misc/apache-kafka.nix
   #./services/misc/autofs.nix
   ./services/misc/cpuminer-cryptonight.nix
   ./services/misc/cgminer.nix

nixos/modules/services/misc/apache-kafka.nix

@@ -0,0 +1,156 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.apache-kafka;
+
+  serverProperties =
+    if cfg.serverProperties != null then
+      cfg.serverProperties
+    else
+      ''
+        # Generated by nixos
+        broker.id=${toString cfg.brokerId}
+        port=${toString cfg.port}
+        host.name=${cfg.hostname}
+        log.dirs=${concatStringsSep "," cfg.logDirs}
+        zookeeper.connect=${cfg.zookeeper}
+        ${toString cfg.extraProperties}
+      '';
+
+  configDir = pkgs.buildEnv {
+    name = "apache-kafka-conf";
+    paths = [
+      (pkgs.writeTextDir "server.properties" serverProperties)
+      (pkgs.writeTextDir "log4j.properties" cfg.log4jProperties)
+    ];
+  };
+
+in {
+
+  options.services.apache-kafka = {
+    enable = mkOption {
+      description = "Whether to enable Apache Kafka.";
+      default = false;
+      type = types.uniq types.bool;
+    };
+
+    brokerId = mkOption {
+      description = "Broker ID.";
+      default = 0;
+      type = types.int;
+    };
+
+    port = mkOption {
+      description = "Port number the broker should listen on.";
+      default = 9092;
+      type = types.int;
+    };
+
+    hostname = mkOption {
+      description = "Hostname the broker should bind to.";
+      default = "localhost";
+      type = types.string;
+    };
+
+    logDirs = mkOption {
+      description = "Log file directories";
+      default = [ "/tmp/kafka-logs" ];
+      type = types.listOf types.path;
+    };
+    
+    zookeeper = mkOption {
+      description = "Zookeeper connection string";
+      default = "localhost:2181";
+      type = types.string;
+    };
+ 
+    extraProperties = mkOption {
+      description = "Extra properties for server.properties.";
+      type = types.nullOr types.lines;
+      default = null;
+    };
+
+    serverProperties = mkOption {
+      description = ''
+        Complete server.properties content. Other server.properties config
+        options will be ignored if this option is used.
+      '';
+      type = types.nullOr types.lines;
+      default = null;
+    };
+
+    log4jProperties = mkOption {
+      description = "Kafka log4j property configuration.";
+      default = ''
+        log4j.rootLogger=INFO, stdout 
+        
+        log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+        log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+        log4j.appender.stdout.layout.ConversionPattern=[%d] %p %m (%c)%n
+      '';
+      type = types.lines;
+    };
+
+    jvmOptions = mkOption {
+      description = "Extra command line options for the JVM running Kafka.";
+      default = [
+        "-server"
+        "-Xmx1G"
+        "-Xms1G"
+        "-XX:+UseCompressedOops"
+        "-XX:+UseParNewGC"
+        "-XX:+UseConcMarkSweepGC"
+        "-XX:+CMSClassUnloadingEnabled"
+        "-XX:+CMSScavengeBeforeRemark"
+        "-XX:+DisableExplicitGC"
+        "-Djava.awt.headless=true"
+        "-Djava.net.preferIPv4Stack=true"
+      ];
+      type = types.listOf types.string;
+      example = [
+        "-Djava.net.preferIPv4Stack=true"
+        "-Dcom.sun.management.jmxremote"
+        "-Dcom.sun.management.jmxremote.local.only=true"
+      ];
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    environment.systemPackages = [pkgs.apacheKafka];
+
+    users.extraUsers = singleton {
+      name = "apache-kafka";
+      uid = config.ids.uids.apache-kafka;
+      description = "Apache Kafka daemon user";
+      home = head cfg.logDirs;
+    };
+
+    systemd.services.apache-kafka = {
+      description = "Apache Kafka Daemon";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-interfaces.target" ];
+      serviceConfig = {
+        ExecStart = ''
+          ${pkgs.jre}/bin/java \
+            -cp "${pkgs.apacheKafka}/libs/*:${configDir}" \
+            ${toString cfg.jvmOptions} \
+            kafka.Kafka \
+            ${configDir}/server.properties
+        '';
+        User = "apache-kafka";
+        PermissionsStartOnly = true;
+      };
+      preStart = ''
+        mkdir -m 0700 -p ${concatStringsSep " " cfg.logDirs}
+        if [ "$(id -u)" = 0 ]; then
+           chown apache-kafka ${concatStringsSep " " cfg.logDirs};
+        fi
+      '';
+    };
+
+  };
+}