Allow COPY command's --chown to be dynamically populated via ENV or ARG #35018
Description
How to use COPY --chown without losing portability (recently merged from this issue)? I'll try to explain with an example wherein I find --chown causing portability issues.
Let's say I got a base image (mybase) which I use for running other containers as non-root user (let's say with UID 1000) using gosu in ENTRYPOINT.
exec /usr/local/bin/gosu ${USER_NAME} "$@"
I use this base image (mybase) for building other container (let's say mycontainer) Dockerfile where I COPY some files from host to container using --chown
FROM mybase
RUN mkdir -p /tmp/build
COPY --chown=1000 . /tmp/build
Now I want the files generated via my build tool (from mycontainer) to be shared on a Docker Volume mapped with my host. Generated files would be available at specified host location but the owner of those files would be user with UID 1000. Doesn't this mean I'll need to have a user with UID 1000 on host machine for generated files to be accessible? Isn't there a way to provide value for --chown dynamically? I tired using ENV and ARG but they are not accessible in --chown.
ARG owner
COPY --chown=$owner . /tmp/build
it gives me an error
unable to convert uid/gid chown string to host mapping: can't find uid for user $owner: no such user: $owner
Steps to reproduce the issue:
- Add this to Dockerfile
FROM openjdk:8
ARG owner
ADD --chown=$owner . /tmp/build/platform3
CMD echo 'test'
- Build image
sudo docker build -t test -f Dockerfile .
Describe the results you received:
Result of running docker build
unable to convert uid/gid chown string to host mapping: can't find uid for user $owner: no such user: $owner
Describe the results you expected:
Expected result should be to get owner information from build arguments
Output of docker version:
Client:
Version: 17.09.0-ce
API version: 1.32
Go version: go1.8.3
Git commit: afdb6d4
Built: Tue Sep 26 22:42:38 2017
OS/Arch: linux/amd64
Server:
Version: 17.09.0-ce
API version: 1.32 (minimum version 1.12)
Go version: go1.8.3
Git commit: afdb6d4
Built: Tue Sep 26 22:41:20 2017
OS/Arch: linux/amd64
Experimental: false
Output of docker info:
Containers: 1
Running: 0
Paused: 0
Stopped: 1
Images: 15
Server Version: 17.09.0-ce
Storage Driver: aufs
Root Dir: /docker/pd0/aufs
Backing Filesystem: extfs
Dirs: 18
Dirperm1 Supported: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 06b9cb35161009dcb7123345749fef02f7cea8e0
runc version: 3f2f8b84a77f73d38244dd690525642a72156c64
init version: 949e6fa
Security Options:
apparmor
Kernel Version: 3.13.0-129-generic
Operating System: Ubuntu 14.04.5 LTS
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 14.69GiB
Name: ip-172-31-35-149
ID: KR63:RIDQ:SQNY:3ESC:5OA6:4DFT:QXSB:YE6M:727G:H7O2:REIS:RSFA
Docker Root Dir: /docker/pd0
Debug Mode (client): false
Debug Mode (server): false
Username: mavericksid
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
127.0.0.0/8
Live Restore Enabled: false
WARNING: No swap limit support