Support multi-dir wildcards in .dockerignore

[Lothiraldan]

Docker-py don't seems compliant with the multi-dir wildcard syntax in .dockerignore.

The corresponding docker issue is moby/moby#13113 and the PR is moby/moby#17090.

It's painful especially for Python projects because we need several level of simple wildcards to ignore .pyc files (see this comment: moby/moby#13113 (comment)).

I've pushed a git repository to reproduce the issue: https://github.com/Lothiraldan/docker-py-wildcarddir-bug

Building it with the official docker client outputs:

$> docker build . --no-cache=true
Sending build context to Docker daemon 6.144 kB
Step 1/3 : FROM ubuntu:14.04
 ---> 4a725d3b3b1c
Step 2/3 : ADD . /code/
 ---> 2a6f8cf084e5
Removing intermediate container c2045ceb345c
Step 3/3 : RUN ls -aRL /code/
 ---> Running in 2b46dc94d237
/code/:
.
..
.dockerignore
Dockerfile
file.py
package

/code/package:
.
..
__init__.py
module.py
sub_package

/code/package/sub_package:
.
..
__init__.py
 ---> 6168100e2dd3
Removing intermediate container 2b46dc94d237
Successfully built 6168100e2dd3

Building it with docker-py outputs (using unreleased master version):

$> python3 build.py
Step 1/3 : FROM ubuntu:14.04
 ---> 4a725d3b3b1c
Step 2/3 : ADD . /code/
 ---> 3a994700e607
Step 3/3 : RUN ls -aRL /code/
 ---> Running in ced581812281
/code/:
.
..
.dockerignore
Dockerfile
build.py
file.py
file.pyc
package

/code/package:
.
..
__init__.py
module.py
sub_package

/code/package/sub_package:
.
..
__init__.py
__init__.pyc
 ---> 0b2c00b86ab6
Successfully built 0b2c00b86ab6

It seems that the docker PR replaced the equivalent of match_path (

docker-py/docker/utils/utils.py

Lines 228 to 235 in b3ea1fb

	def match_path(path, pattern):
	pattern = pattern.rstrip('/' + os.path.sep)
	if pattern:
	pattern = os.path.relpath(pattern)
	pattern_components = pattern.split(os.path.sep)
	path_components = path.split(os.path.sep)[:len(pattern_components)]
	return fnmatch('/'.join(path_components), pattern)

) by a regex here https://github.com/docker/docker/pull/17090/files#diff-d293110531a98dc2d3a48d6f48226c51R122.

I don't know if there is a better option to support it in Python. I've also checked https://pypi.python.org/pypi/glob2/0.5 as it seems to support it but the double-wildcard support ** is made recursively at the directory walking level and not the path matching level.

Python version: 3.5.2
OS: Mac OS X 10.11.6
Docker-py: master (b3ea1fb)

I'm planning to take some times trying to do a PR for the support.

[shin-]

Hi!

This is a known limitation of our implementation that is on our TODO list. See the original report: #1117