Docker: adding a file from a parent directory

问题:

In my Dockerfile I've got :

ADD ../../myapp.war /opt/tomcat7/webapps/

That file exists as ls ../../myapp.war returns me the correct file but when I execute sudo docker build -t myapp . I've got :

Step 1 : ADD ../../myapp.war /opt/tomcat7/webapps/
2014/07/02 19:18:09 ../../myapp.war: no such file or directory

Does somebody know why and how to do it correctly?

回答1:

You can build the Dockerfile from the parent directory:

docker build -t <some tag> -f <dir/dir/Dockerfile> .

回答2:

Unfortunately, (for practical and security reasons I guess), if you want to add/copy local content, it must be located under the same root path than the Dockerfile.

From the documentation:

The <src> path must be inside the context of the build; you cannot ADD ../something/something, because the first step of a docker build is to send the context directory (and subdirectories) to the docker daemon.

EDIT: There's now an option (-f) to set the path of your Dockerfile ; it can be used to achieve what you want, see @Boedy 's response nelow.

回答3:

With docker-compose you could set context folder:

#docker-compose.yml
version: '3.3'    
services:
      yourservice:
        build:
          context: ./
          dockerfile: ./docker/yourservice/Dockerfile

回答4:

The solution for those who use composer is to use a volume pointing to the parent folder:

#docker-composer.yml

foo:
  build: foo
  volumes:
    - ./:/src/:ro

But I'm pretty sure the can be done playing with volumes in Dockerfile.

回答5:

Since -f caused another problem, I developed another solution.

• Create a base image in the parent folder
• Added the required files.
• Used this image as a base image for the project which in a descendant folder.

The -f flag does not solved my problem because my onbuild image looks for a file in a folder and had to call like this:

-f foo/bar/Dockerfile foo/bar

instead of

-f foo/bar/Dockerfile .

Also note that this is only solution for some cases as -f flag