Composer could not find a composer.json file in /app

[yveshema]

I am trying to follow the official guide to install dependencies for my Laravel project. When I run this command:

$ docker run --rm --interactive --tty \
  --volume $PWD:/app \
  composer install

it throws the following error:
Composer could not find a composer.json file in /app
To initialize a project, please create a composer.json file as described in the https://getcomposer.org/ "Getting Started" section

I came here looking for answers and saw that the issue appears to be a common one, but it appears a solution is yet to be found.
I am running this on a Fedora machine and docker version: 19.03.11
I am hoping someone had the same issue and maybe found an workaround.

[wglambert]

Composer isn't in the php image, there was a discussion on that here docker-library/php#344

There were also some examples in there for installing composer docker-library/php#344 (comment)

You could also try asking over at the Docker Community Forums, Docker Community Slack, or Stack Overflow. Since these repos aren't really a user-help forum

[yveshema]

After a lot of googling, I was able to solve the issue. It turns out it was selinux related. [This stackoverflow thread] (https://stackoverflow.com/questions/24288616/permission-denied-on-accessing-host-directory-in-docker) provides a comprehensive explanation. In a nutshell, the contents of the mounted folder need to be re-labelled properly (notice the 'z' flag) to enable read access to the files, like so:

$ docker run --rm --interactive --tty \
  --volume $PWD:/app:z \
  composer install

For clarity, I was actually not using the php image. I was using the official Composer image to generate the vendor files which I relied on for building a custom php image.

[wglambert]

Cool glad you got it figured out. For the Composer image we don't maintain that ourselves, their repo is over at https://github.com/composer/docker/issues

https://hub.docker.com/_/composer
Maintained by: Rob Bast, with contributions from the community.
Where to file issues: https://github.com/composer/docker/issues

Going to close since this is resolved