Not working add_metadata_from_env in logstash v5.1.1

[phirov]

The configure option add_metadata_from_env is not working.

System info is here:

• Version: logstash 5.1.1
• Operating System: official docker image of logstash:5.1.1
• Config File:

input {
    stdin { }
}

filter {
    environment {
        add_metadata_from_env => {
            "home1" => "HOME"
        }
        add_field => {
            "home2" => "${HOME}"
        }
    }
}

output {
    stdout {
        codec => rubydebug
    }
}

• Sample Data:

Sending Logstash's logs to /var/log/logstash which is now configured via log4j2.properties
The stdin plugin is now waiting for input:
09:05:20.762 [[main]-pipeline-manager] INFO  logstash.pipeline - Starting pipeline {"id"=>"main", "pipeline.workers"=>1, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>5, "pipeline.max_inflight"=>125}
09:05:20.770 [[main]-pipeline-manager] INFO  logstash.pipeline - Pipeline main started
09:05:20.845 [Api Webserver] INFO  logstash.agent - Successfully started Logstash API endpoint {:port=>9600}
aaaa
{
    "@timestamp" => 2017-02-14T09:05:24.998Z,
      "@version" => "1",
          "host" => "696a6caef712",
       "message" => "aaaa",
          "tags" => [],
         "home2" => "/root"
}

[xapn]

You must use the following option to read metadata with logstash-output-stdout.

output { 
  stdout { 
    codec  => rubydebug {
      metadata => true
    }
  }
}

Source: Make Your Config Cleaner and your Log Processing Faster with Logstash Metadata