Docker-py: FileNotFoundError in docker/api/build.py:154 from docker-compose with context and custom dockerfile

[mlazze]

$> pip freeze | grep docker && python --version && docker version
docker==3.2.0
docker-compose==1.20.1
docker-pycreds==0.2.2
dockerpty==0.4.1
Python 3.6.4
Client:
 Version: 18.03.0-ce
 API version: 1.37
 Go version: go1.10
 Git commit: 0520e24302
 Built: Fri Mar 23 01:47:41 2018
 OS/Arch: linux/amd64
 Experimental: false
 Orchestrator: swarm

Server:
 Engine:
  Version: 18.03.0-ce
  API version: 1.37 (minimum version 1.12)
  Go version: go1.10
  Git commit: 0520e24302
  Built: Fri Mar 23 01:48:12 2018
  OS/Arch: linux/amd64
  Experimental: false

$> pwd
/tmp/tmp.sYItnmyls8



md5-a63031b3fb9ef7bf6de02261a251f0f7



$> tree 
.
├── context
│   └── CustomDockerFile
└── docker-compose.yml



md5-a63031b3fb9ef7bf6de02261a251f0f7



$> cat docker-compose.yml
version: "3"

services:
    testservice:
        build:
            context: ./context
            dockerfile: CustomDockerFile



md5-a63031b3fb9ef7bf6de02261a251f0f7



$> cat context/CustomDockerFile
FROM scratch



md5-a63031b3fb9ef7bf6de02261a251f0f7



$> docker-compose build
Building testservice
Traceback (most recent call last):
  File "/usr/bin/docker-compose", line 11, in <module>
    load_entry_point('docker-compose==1.20.1', 'console_scripts', 'docker-compose')()
  File "/usr/lib/python3.6/site-packages/compose/cli/main.py", line 71, in main
    command()
  File "/usr/lib/python3.6/site-packages/compose/cli/main.py", line 127, in perform_command
    handler(command, command_options)
  File "/usr/lib/python3.6/site-packages/compose/cli/main.py", line 280, in build
    build_args=build_args)
  File "/usr/lib/python3.6/site-packages/compose/project.py", line 372, in build
    service.build(no_cache, pull, force_rm, memory, build_args)
  File "/usr/lib/python3.6/site-packages/compose/service.py", line 998, in build
    'memory': parse_bytes(memory) if memory else None
  File "/usr/lib/python3.6/site-packages/docker/api/build.py", line 154, in build
    with open(dockerfile, 'r') as df:
FileNotFoundError: [Errno 2] No such file or directory: 'CustomDockerFile'

This is caused by https://github.com/docker/docker-py/pull/1977/files#diff-e1d542dae5b9c86ba6a8242ebd3f5df6R152 .

path = '/tmp/tmp.sYItnmyls8/context'
dockerfile = 'CustomDockerFile'

os.path.relpath(dockerfile, path) in this context returns '../CustomDockerFile'

Am i missing something evident?

[make-it-git]

Same issue for me.
I had to downgrade python-docker to version 3.1.4.1 and it works.

[shin-]

Thanks for the report!

[shin-]

Just released 3.2.1 with the fix!