docker-compose copy file or directory to container

we miss a possibility to copy a file or directory using docker-compose. I find this really useful.
Please check many +1 in premature closed #2105

[shin-]

What's the usecase? Most of the suggested usage I've seen were antipatterns.

You can see some of many usecases clicking at link provided. As you can see many of subscribers consider it as really useful feature instead of "antipattern"

ooops, now I see "something" happened to issue #2105 as there are no comments at all anymore...
Perhaps I provided wrong link...

so, I find really useful to copy some configuration/initialization files to container. As example some *.sql stuff for db containers, some html/js/css content for apache/nginx containers or even jar file for java container. This will make it available/runnable "globally" not only on machine where it was composed as in case of mounting volume(s). Mainly this will be some combination of host-local and container-contained files. In fact any container can be considered useless without any configuration or initialization

this is correct link: #1664

[ukbe]

+1

[shin-]

This will make it available/runnable "globally" not only on machine where it was composed as in case of mounting volume(s)

The problem with this is that it is incredibly short-sighted (hence the term "anti-pattern"), as it will force you to repeat the operation every time the containers to be recreated. Not to mention the fact that it scales very poorly (what if you have 10 containers? 20? 100?)

The actual solution to your issue is to include those necessary files in your build (Dockerfile) and rebuild when an update is needed.

of course, if it is composed including all "shared" content into container, scaling 10-20-100- containers would be much easier. Everything you need is to pull it from repository and mount(yes, in this case mount) only node-specific config. And even more, you don't need run docker-compose on each node.
Sure we can use docker-compose in combination with build: & Dockerfile, however things become little more complex and yaml configuration in docker-compose is much more "elegant" :o)

[dkinzer]

I'm running into an issue where copy would come in handy (at least as an override). I mostly develop on mac so I almost never see an issue with commands running as root in the container and exporting to a mounted volume. However, recently using the same workflow on a CentOs has caused some major pain because files owned by the root user are being added to the host via the mounted volume. I would like in these cases to just be able to copy the host files to the container instead of mounting them.

The related issue: #1532

update

I think in my case I can get away with using COPY in the Dockerfile and having multiple docker-compose files one of which uses a volume mount.

[nrdmn]

Use case: starting multiple docker containers simultaneously from .gitlab-ci.yml which need to write into the git repository's directory.

If the process inside a container fails or if the ci job is cancelled before the container has cleaned up after itself, the remaining files can't be deleted by gitlab-runner due to lack of permissions. Now I could copy the files within the container out of the volume into another directory, but that would be an antipattern, wouldn't it?

[harpratap]

Is this different from volumes: - ./folder_on_host/ :/folder_in_container/ ?
I am able to copy files from host to container (equivalent of COPY) this way in my compose file

[justin-vanwinkle]

@harpratap you are right, but the drawback is that /folder_in_container must not exist or must be empty or else it will be overwritten. If you have a bash script as your entry point, you could circumvent this by symlinking your files into the originally intended directory after you create a volume at /some_empty_location

+1 for having a COPY functionality. Our use case is for rapidly standing up local development environments and copying in configs for the dev settings.

[djelroy]

+1 for COPY. This would really be a helpful feature.

Use case: in swarm mode, I have a service using mysql image. I need to copy my initialization scripst in /docker-entrypoint-initdb.d/ so that MySQL can execute them.

Though it is possible to create an image on top of mysql, copy the files and use it or connect to the mysql
task in swarm and then manually run the scripts, it's kinda unnecessary in my opinion.

[AnishAnil]

+1 for COPY/ADD,

Use Case:
Fluentd requires the configuration files to be moved into the container during run time. These config files are created on the run time by our Jenkins Engine and without a COPY/ADD in docker compose it simply fails.

[mbao01]

+1 for COPY