logstash service improvements

* add logstash-contrib plugins package
* add additional options to the logstash service

pkgs/tools/misc/logstash/contrib.nix

@@ -0,0 +1,31 @@
+{ stdenv, lib, fetchzip }:
+
+# Note that plugins are supposed to be installed as:
+#   $path/logstash/{inputs,codecs,filters,outputs}/*.rb 
+stdenv.mkDerivation rec {
+  version = "1.4.2";
+  name = "logstash-contrib-${version}";
+
+  src = fetchzip {
+   url = "http://download.elasticsearch.org/logstash/logstash/logstash-contrib-${version}.tar.gz";
+   sha256 = "1yj8sf3b526gixh3c6zhgkfpg4f0c72p1lzhfhdx8b3lw7zjkj0k";
+  };
+
+  dontBuild    = true;
+  dontPatchELF = true;
+  dontStrip    = true;
+  dontPatchShebangs = true;
+
+  installPhase = ''
+    mkdir -p $out/logstash
+    cp -r lib/* $out
+  '';
+
+  meta = with lib; {
+    description = "Community-maintained logstash plugins";
+    homepage    = https://github.com/elasticsearch/logstash-contrib;
+    license     = stdenv.lib.licenses.asl20;
+    platforms   = stdenv.lib.platforms.unix;
+    maintainers = with maintainers; [ cstrahan ];
+  };
+}