I have based this branch on v0.6.4 tag. Performed tests as described in [1].

The test output of the unpatched and patched binaries looks almost same, except for the timestamp differences and container ID diffs.

[1] http://docs.docker.io/en/latest/contributing/devenvironment/

I forgot to add that one of the pain points I have with the dockerfile-via-stdin feature (the dash - option) is that it does not have a context with it. So, Docker wouldn't allow me to use the ADD command since ADD requires a context.

The alternative feature, and possibly easier to accept in core, would be allow the stdin option to have a context with it. Say, -context some_dir/, and only in case of stdin processing, Docker frontend would tar the optional some_dir/ as context and sent to the backend.

Looks like commit wagerlabs/docker@65694e801a7b80930961d70c69cba9f2465459be will make it very easy to add new commands. Thankfully I did not put in a lot of effort in this commit, only to redo it using the new parser support :)

@gurjeet, I am not comfortable merging this because it breaks the 1-to-1 relationship between a source directory and the resulting container image. You don't actually build a Dockerfile: you build a directory with the help of the Dockerfile inside that directory.

In your example, the correct approach is this:

docker build -t db_container ./db
docker build -t web_container ./web
docker build -t client_container ./client
docker build -t client_container .

This leaves open the problem of sharing source content between ./client and ./web for example. I don't yet have an answer to that particular problem. But 99% of the people asking me for this feature don't actually need to share source content - so all you need to do is create different directories with a Dockerfile in each.

@shykes I gets building a directory but it would be nice to have a default dockerfile and others that often share the same directory structure. Especially for dockerfiles that start at a child file.