composer home directory not writable when running as custom user

[alcohol]

When running the Composer image as follows

docker run --rm \
  --volume /etc/passwd:/etc/passwd:ro \
  --volume /etc/group:/etc/group:ro \
  --user $(id -u):$(id -g) \
  composer install

the default COMPOSER_HOME (/composer) cannot be written to by the user which is used to run the process. Since these Containers are ephemeral and single-run only, I am not sure if having a writable cache is of any use. Regardless, it would be nice to avoid having Composer throw warnings around.

[meteorlxy]

Maybe we can use something like --volume ~/.composer/cache:/composer/cache:rw to enable the cache?

[alcohol]

I defaulted the COMPOSER_HOME to /tmp in the image template. The next release should see this change. So in future release (> 1.4.2) you can do --volume ~/.composer/cache:/tmp/cache:rw.

I chose this solution because /tmp generally does not have any permission issues.

[meteorlxy]

I see. BTW, is there a way to change the default packagist source globally? I have to make a new image adding RUN composer config -g repo.packagist composer https://custom.packagist.source

[alcohol]

Your solution is the only way to make it an explicit default in the image/container itself.

Alternatively, you can mount your Composer home directory (~/.composer usually) onto /tmp inside the image (assuming the composer configuration on your host has this desired default changed).

[bicpi]

This change is not yet reflected in the docs.

[alcohol]

It should be soon. docker-library/docs#981