如何用无花果指定写入权限

用docker -v选项，我们可以像下面那样指定写入权限

docker run -d --name web -v /etc/localtime:/etc/localtime:ro 

其中ro表示只读访问。

我们如何用无花果做到这一点？ 如果

 pg: image: xxxxxxxxxxxxxx/postgres:9.1-1 web: image: xxxxxxxxxxxxxx/unicorn:0.0.2 volumes: - /etc/localtime:/etc/localtime:ro - .:/src links: - pg:server_pg command: /bin/bash -xe something.sh 

在上面的例子中：ro在卷段中引起以下错误

 Traceback (most recent call last): File "<string>", line 3, in <module> File "/code/build/fig/out00-PYZ.pyz/fig.cli.main", line 39, in main File "/code/build/fig/out00-PYZ.pyz/fig.cli.docopt_command", line 21, in sys_dispatch File "/code/build/fig/out00-PYZ.pyz/fig.cli.command", line 31, in dispatch File "/code/build/fig/out00-PYZ.pyz/fig.cli.docopt_command", line 24, in dispatch File "/code/build/fig/out00-PYZ.pyz/fig.cli.command", line 50, in perform_command File "/code/build/fig/out00-PYZ.pyz/fig.cli.docopt_command", line 27, in perform_command File "/code/build/fig/out00-PYZ.pyz/fig.cli.main", line 306, in up File "/code/build/fig/out00-PYZ.pyz/fig.project", line 131, in up File "/code/build/fig/out00-PYZ.pyz/fig.service", line 173, in recreate_containers File "/code/build/fig/out00-PYZ.pyz/fig.service", line 195, in recreate_container File "/code/build/fig/out00-PYZ.pyz/fig.service", line 225, in start_container ValueError: too many values to unpack