filter-codec idea

[colinsurprenant]

@jsvd suggested some time ago to create a filter that could leverage codecs to do the filtering which would have the advantage of avoiding dual codec/filter implementations like the json codec and filter - we could have only the json codec and leverage the json codec into a filter-codec to create a json filter.

This issue is to keep a trace & followup on that idea.

Also, the same has been suggested for xml in logstash-plugins/logstash-filter-xml#22

[jsvd]

my experiment with creating a logstash-filter-codec is in https://github.com/jsvd/logstash-filter-codec

[jsvd]

more about the current functionality:

# decoding
% echo '{"test": "hey" }' | bin/logstash -e 'input { stdin {} } filter { codec { codec => json mode => decode } }  output { stdout { codec => rubydebug } }'
{
          "test" => "hey",
      "@version" => "1",
    "@timestamp" => "2015-12-28T13:45:37.344Z"
}

# encoding
% bin/logstash -e 'input { generator { count => 1 } } filter { codec { codec => json mode => encode } }  output { stdout { codec => rubydebug } }' 
{
       "message" => "{\"message\":\"Hello world!\",\"@version\":\"1\",\"@timestamp\":\"2015-12-28T13:46:14.657Z\",\"host\":\"Joaos-MBP.lan\",\"sequence\":0}",
      "@version" => "1",
    "@timestamp" => "2015-12-28T13:46:14.918Z"
}

[purbon]

I find this very interesting, we should enforce the idea of having code not duplicated and this could help.