Logstash - GELF output error
<p>I've installed Graylog v2.1.1 as a virtual appliance inside VirtualBox on a Windows 7 PC.</p>

<p>I'm trying to read a simple log file and forward it to Graylog by using <code>logstash v5.0.0</code> with the <code>logstash-output-gelf-3.1.1</code> plugin, as described here: <a href="https://stackoverflow.com/a/31054064/4863804">https://stackoverflow.com/a/31054064/4863804</a>.</p>

<p>I've set up the following  <code>logstash.conf</code> output:</p>

<pre><code>input { 
  file {...}
}

output {
  gelf {
    host =&gt; "199.99.99.179"
    port =&gt; 12203
  }
}
</code></pre>

<p>But after running <code>logstash -f logstash.conf</code> I get the following error:</p>

<pre><code>[2016-10-28T14:52:17,756][INFO ][logstash.pipeline        ] Pipeline main started
[2016-10-28T14:52:17,817][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=&gt;9600}
[2016-10-28T14:52:18,594][FATAL][logstash.runner          ] An unexpected error occurred! {:error=&gt;#&lt;NameError: no method 'debug' for arguments (org.jruby.RubyArray,org.jruby.RubyHash) on Java::OrgApacheLoggingLog4jCore::Logger
  available overloads:
    (org.apache.logging.log4j.Marker,java.lang.String,java.lang.Object[])
    (org.apache.logging.log4j.Marker,java.lang.String,org.apache.logging.log4j.util.Supplier[])
    (java.lang.String,org.apache.logging.log4j.util.Supplier[])
    (java.lang.String,java.lang.Object[])&gt;, :backtrace=&gt;["C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/logging/logger.rb:41:in `debug'", "C:/SDKs/logstash-5.0.0/vendor/bundle/jruby/1.9/gems/logstash-output-gelf-3.1.1/lib/logstash/outputs/gelf.rb
:190:in `receive'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/outputs/base.rb:92:in `multi_receive'", "org/jruby/RubyArray.java:1613:in `each'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/outputs/base.rb:92:in `multi_receive'", "C:/S
DKs/logstash-5.0.0/logstash-core/lib/logstash/output_delegator_strategies/legacy.rb:19:in `multi_receive'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/output_delegator.rb:42:in `multi_receive'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logst
ash/pipeline.rb:297:in `output_batch'", "org/jruby/RubyHash.java:1342:in `each'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/pipeline.rb:296:in `output_batch'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/pipeline.rb:252:in `worker_loo
p'", "C:/SDKs/logstash-5.0.0/logstash-core/lib/logstash/pipeline.rb:225:in `start_workers'"]}
</code></pre>