code: public Map<String, String> containerEnv() {
      final Map<String, String> env = Maps.newHashMap(envVars);
  
      // Put in variables that tell the container where it's exposed
      for (final Entry<String, Integer> entry : ports.entrySet()) {
        env.put("HELIOS_PORT_" + entry.getKey(), host + ":" + entry.getValue());
      }
      // Job environment variables take precedence.
      env.putAll(job.getEnv());
      return env;
    }
docs: Get environment variables for the container.
  
  @return The environment variables.