title: docker-compose json logging driver labels/env
body: <p>I have been trying to get logs in format:</p>
  
  <pre><code>{"log":"Using CATALINA_BASE:   /opt/apache-tomcat-
  7.0.76\r\n","stream":"stdout","time":"2017-04-
  19T04:28:33.608418994Z","attrs":
  {"production_status":"testing","os":"ubuntu"}}
  </code></pre>
  
  <p>I am using docker-compose.yml :</p>
  
  <pre><code>version: '2.1'
  services:
    web:
      image: hello-world/web:latest
      container_name: api
      ports:
        - "80:8080"
  logging:
    driver: "json-file"
    options:
      max-size: 10m
      max-file: "3"
      labels: testing
      env: ubuntu
  </code></pre>
  
  <p>But I do not get "attrs" key in logs. What am I doing wrong?</p>