docker-compose 1.6 "args" attribute on "build"
<p>I'm trying to use the new "args" attribute to pass variable to Dockerfile build. But the yaml parser is not accepting the parameter.</p>

<pre><code>ERROR: yaml.scanner.ScannerError: mapping values are not allowed here
</code></pre>

<p>For version 2 of docker-compose.yml the requirements are docker-compose 1.6+ and docker-engine 1.10+ and I have both them installed. </p>

<p>This is part of my docker-compose file:</p>

<pre><code>version: '2'
services:
 solr:
    build: ./solr
      args:
        solr_port: 8983
    volumes:
      - ./apps/solr-conf:/opt/solr/server/solr
    ports:
      - 8983:8983
</code></pre>

<p>The error refers to the "args" line. </p>