Closed
Description
Scenario:
Files
Dockerfile:
FROM ubuntu:14.04
ARG FOO=1
RUN echo "-${FOO}-"
CMD /bin/bash
docker-compose.yml:
version: '2'
services:
test:
build:
context: .
args:
- FOO
Execution:
$ ./docker-compose-1.6.2 --verbose config
compose.config.config.find: Using configuration files: ./docker-compose.yml
networks: {}
services:
test:
build:
args:
FOO: None
context: /home/riccardi/git/ses-docker/test-default-build-arg
version: '2.0'
volumes: {}
$ ./docker-compose-1.6.2 --verbose build
compose.config.config.find: Using configuration files: ./docker-compose.yml
docker.auth.auth.load_config: File doesn't exist
compose.cli.command.get_client: docker-compose version 1.6.2, build 4d72027
docker-py version: 1.7.2
CPython version: 2.7.9
OpenSSL version: OpenSSL 1.0.1e 11 Feb 2013
compose.cli.command.get_client: Docker base_url: http+docker://localunixsocket
compose.cli.command.get_client: Docker version: KernelVersion=4.2.0-35-generic, Os=linux, BuildTime=2016-03-10T15:54:52.312835708+00:00, ApiVersion=1.22, Version=1.10.3, GitCommit=20f81dd, Arch=amd64, GoVersion=go1.5.3
compose.service.build: Building test
compose.cli.verbose_proxy.proxy_callable: docker build <- (pull=False, stream=True, nocache=False, tag=u'testdefaultbuildarg_test', buildargs={u'FOO': 'None'}, rm=True, forcerm=False, path='/home/riccardi/git/ses-docker/test-default-build-arg', dockerfile=None)
docker.api.build._set_auth_headers: Looking for auth config
docker.api.build._set_auth_headers: No auth config in memory - loading from filesystem
docker.auth.auth.load_config: File doesn't exist
docker.api.build._set_auth_headers: No auth config found
compose.cli.verbose_proxy.proxy_callable: docker build -> <generator object _stream_helper at 0x7f56bafb3a50>
Step 1 : FROM ubuntu:14.04
---> b549a9959a66
Step 2 : ARG FOO=1
---> Using cache
---> 4774113d6ec5
Step 3 : RUN echo "-${FOO}-"
---> Running in dabd31837074
-None-
---> f8a99349af3b
Removing intermediate container dabd31837074
Step 4 : CMD /bin/bash
---> Running in 487f5e789c38
---> 6c484f426fb5
Removing intermediate container 487f5e789c38
Successfully built 6c484f426fb5
compose.cli.verbose_proxy.proxy_callable: docker close <- ()
compose.cli.verbose_proxy.proxy_callable: docker close -> None
( same result with 1.7.1-rc1 which includes PR #2938 )
Issue
Expected result:
prints -1-.
Actual result:
prints -None-.
Details:
Compose has no value for FOO build arg from its environment, so it could either send an empty string to docker build, or better: not send this build arg to docker build.
The second one would be great: it would open the possibility to use the default value for the build arg as defined in the Dockerfile. ( For now the workaround is to duplicate the default values from Dockerfile to .env, only works with >=1.7.0).
The first one would be still better than the current behavior.
Current behavior: no value in Compose environment is represented in python as None, then casted to a string "None", which is probably always bad.
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