I'm trying to use the dead_letter_queue input plugin to reintroduce Elasticsearch events that get dropped back into the Logstash pipe and tag them. It appears as the Logstash 5.5 distribution fails to find the dead_letter_queue input when it is put into the configuration file.
My config looks like this:
dead_letter_queue {
path => "/home/logstash/logstash/data/dead_letter_queue"
}
And I do have dead_letter_queue.enable set to true in logstash.yml.
Here is the error I receive when Logstash starts up:
Jul 11 11:34:56 <HIDDEN> logstash[18488]: [2017-07-11T11:34:56,396][ERROR][logstash.plugins.registry] Problems loading a plugin with {:type=>"input", :name=>"dead_letter_queue", :path=>"logstash/input
s/dead_letter_queue", :error_message=>"NameError", :error_class=>NameError, :error_backtrace=>["/home/logstash/logstash/logstash-core/lib/logstash/plugins/registry.rb:226:in `namespace_lookup'", "/home/logstash/logstash/logstash-co
re/lib/logstash/plugins/registry.rb:162:in `legacy_lookup'", "/home/logstash/logstash/logstash-core/lib/logstash/plugins/registry.rb:138:in `lookup'", "/home/logstash/logstash/logstash-core/lib/logstash/plugins/registry.rb:180:in `
lookup_pipeline_plugin'", "/home/logstash/logstash/logstash-core/lib/logstash/plugin.rb:140:in `lookup'", "/home/logstash/logstash/logstash-core/lib/logstash/pipeline.rb:100:in `plugin'", "(eval):256:in `initialize'", "org/jruby/Ru
byKernel.java:1079:in `eval'", "/home/logstash/logstash/logstash-core/lib/logstash/pipeline.rb:72:in `initialize'", "/home/logstash/logstash/logstash-core/lib/logstash/pipeline.rb:156:in `initialize'", "/home/logstash/logstash/logs
tash-core/lib/logstash/agent.rb:286:in `create_pipeline'", "/home/logstash/logstash/logstash-core/lib/logstash/agent.rb:95:in `register_pipeline'", "/home/logstash/logstash/logstash-core/lib/logstash/runner.rb:314:in `execute'", "/
home/logstash/logstash/vendor/bundle/jruby/1.9/gems/clamp-0.6.5/lib/clamp/command.rb:67:in `run'", "/home/logstash/logstash/logstash-core/lib/logstash/runner.rb:209:in `run'", "/home/logstash/logstash/vendor/bundle/jruby/1.9/gems/c
lamp-0.6.5/lib/clamp/command.rb:132:in `run'", "/home/logstash/logstash/lib/bootstrap/environment.rb:71:in `(root)'"]}
Jul 11 11:34:56 <HIDDEN> logstash[18488]: [2017-07-11T11:34:56,402][ERROR][logstash.agent ] Cannot create pipeline {:reason=>"Couldn't find any input plugin named 'dead_letter_queue'. Are yo
u sure this is correct? Trying to load the dead_letter_queue input plugin resulted in this error: Problems loading the requested plugin named dead_letter_queue of type input. Error: NameError NameError"}
Removing the dead_letter_queue plugin through the Logstash plugin-install script and reinstalling it doesn't fix the problem. I can confirm that the plugin dead_letter_queue is listed when I do ./bin/logstash-plugin list.
I'm running Logstash on RHEL 7.3.