Historically, the Dockerfile had to be insde the build-context, because it was
sent as part of the build-context.
3f6dc81e10
added support for passing the Dockerfile through stdin, in which case the
contents of the Dockerfile is injected into the build-context.
This patch uses the same mechanism for situations where the location of the
Dockerfile is passed, and its path is outside of the build-context.
Before this change:
$ mkdir -p myproject/context myproject/dockerfiles && cd myproject
$ echo "hello" > context/hello
$ echo -e "FROM busybox\nCOPY /hello /\nRUN cat /hello" > dockerfiles/Dockerfile
$ docker build --no-cache -f $PWD/dockerfiles/Dockerfile $PWD/context
unable to prepare context: the Dockerfile (/Users/sebastiaan/projects/test/dockerfile-outside/myproject/dockerfiles/Dockerfile) must be within the build context
After this change:
$ mkdir -p myproject/context myproject/dockerfiles && cd myproject
$ echo "hello" > context/hello
$ echo -e "FROM busybox\nCOPY /hello /\nRUN cat /hello" > dockerfiles/Dockerfile
$ docker build --no-cache -f $PWD/dockerfiles/Dockerfile $PWD/context
Sending build context to Docker daemon 2.607kB
Step 1/3 : FROM busybox
---> 6ad733544a63
Step 2/3 : COPY /hello /
---> 9a5ae1c7be9e
Step 3/3 : RUN cat /hello
---> Running in 20dfef2d180f
hello
Removing intermediate container 20dfef2d180f
---> ce1748f91bb2
Successfully built ce1748f91bb2
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
