Running composer through docker container sharing SSH Auth, users, cache dir etc.
docker run -it --rm \
--env COMPOSER_HOME \
--env SSH_AUTH_SOCK=/ssh-auth.sock \
--user $UID:$GID \
--volume $SSH_AUTH_SOCK:/ssh-auth.sock \
--volume /etc/passwd:/etc/passwd:ro \
--volume /etc/group:/etc/group:ro \
--volume ${COMPOSER_HOME:-$HOME/.composer}:/tmp \
--volume $PWD:/app \
-w /app \
composer