WP-CLI file permission problems using Docker volumes - wordpress

Question

wordpress:cli container is not able to manipulate files on a volume shared with wordpress container.
Here's the docker-compose.yml file I use to bootstrap WordPress:
version: "3"
services:
wordpress:
image: wordpress
ports: ["80:80"]
volumes: ["wp_test:/var/www/html"]
environment:
WORDPRESS_DB_NAME: wordpress
WORDPRESS_DB_USER: root
WORDPRESS_DB_PASSWORD: secret
mysql:
image: mysql
environment:
MYSQL_ROOT_PASSWORD: secret
cli:
image: wordpress:cli
volumes: ["wp_test:/var/www/html"]
command: sh -c "sleep 20 && wp core install --path=/var/www/html --url=localhost --title=test --admin_user=test --admin_password=test --admin_email=test#example.com"
volumes:
wp_test:
I start it with docker-compose up and when wp-cli sets up the installation, there is a warning:
cli_1 | Warning: Unable to create directory wp-content/uploads/2018/02. Is its parent directory writable by the server?
The installation works so far, but I'd like to fix this warning, because for other wp-cli tasks manipulating files is critical.
From inside wordpress container, privileges look like this:
drwxr-xr-x 5 www-data www-data 4096 Feb 2 11:21 .
drwxr-xr-x 4 root root 4096 Jan 4 01:30 ..
-rw-r--r-- 1 www-data www-data 234 Feb 2 11:21 .htaccess
-rw-r--r-- 1 www-data www-data 418 Sep 25 2013 index.php
-rw-r--r-- 1 www-data www-data 19935 Jan 6 19:32 license.txt
-rw-r--r-- 1 www-data www-data 7413 Dec 12 2016 readme.html
-rw-r--r-- 1 www-data www-data 5434 Sep 23 12:21 wp-activate.php
drwxr-xr-x 9 www-data www-data 4096 Jan 16 21:39 wp-admin
-rw-r--r-- 1 www-data www-data 364 Dec 19 2015 wp-blog-header.php
-rw-r--r-- 1 www-data www-data 1627 Aug 29 2016 wp-comments-post.php
-rw-r--r-- 1 www-data www-data 2764 Feb 2 11:21 wp-config-sample.php
-rw-r--r-- 1 www-data www-data 3144 Feb 2 11:21 wp-config.php
drwxr-xr-x 4 www-data www-data 4096 Feb 2 11:22 wp-content
-rw-r--r-- 1 www-data www-data 3669 Aug 20 04:37 wp-cron.php
drwxr-xr-x 18 www-data www-data 12288 Jan 16 21:39 wp-includes
-rw-r--r-- 1 www-data www-data 2422 Nov 21 2016 wp-links-opml.php
-rw-r--r-- 1 www-data www-data 3306 Aug 22 11:52 wp-load.php
-rw-r--r-- 1 www-data www-data 36583 Oct 13 02:10 wp-login.php
-rw-r--r-- 1 www-data www-data 8048 Jan 11 2017 wp-mail.php
-rw-r--r-- 1 www-data www-data 16246 Oct 4 00:20 wp-settings.php
-rw-r--r-- 1 www-data www-data 30071 Oct 18 17:36 wp-signup.php
-rw-r--r-- 1 www-data www-data 4620 Oct 23 22:12 wp-trackback.php
-rw-r--r-- 1 www-data www-data 3065 Aug 31 2016 xmlrpc.php
but from within cli container the same volume looks like this:
drwxr-xr-x 5 www-data www-data 4096 Feb 2 11:21 .
drwxr-xr-x 3 root root 4096 Jan 10 07:36 ..
-rw-r--r-- 1 xfs xfs 234 Feb 2 11:21 .htaccess
-rw-r--r-- 1 xfs xfs 418 Sep 25 2013 index.php
-rw-r--r-- 1 xfs xfs 19935 Jan 6 19:32 license.txt
-rw-r--r-- 1 xfs xfs 7413 Dec 12 2016 readme.html
-rw-r--r-- 1 xfs xfs 5434 Sep 23 12:21 wp-activate.php
drwxr-xr-x 9 xfs xfs 4096 Jan 16 21:39 wp-admin
-rw-r--r-- 1 xfs xfs 364 Dec 19 2015 wp-blog-header.php
-rw-r--r-- 1 xfs xfs 1627 Aug 29 2016 wp-comments-post.php
-rw-r--r-- 1 xfs xfs 2764 Feb 2 11:21 wp-config-sample.php
-rw-r--r-- 1 xfs xfs 3144 Feb 2 11:21 wp-config.php
drwxr-xr-x 4 xfs xfs 4096 Feb 2 11:22 wp-content
-rw-r--r-- 1 xfs xfs 3669 Aug 20 04:37 wp-cron.php
drwxr-xr-x 18 xfs xfs 12288 Jan 16 21:39 wp-includes
-rw-r--r-- 1 xfs xfs 2422 Nov 21 2016 wp-links-opml.php
-rw-r--r-- 1 xfs xfs 3306 Aug 22 11:52 wp-load.php
-rw-r--r-- 1 xfs xfs 36583 Oct 13 02:10 wp-login.php
-rw-r--r-- 1 xfs xfs 8048 Jan 11 2017 wp-mail.php
-rw-r--r-- 1 xfs xfs 16246 Oct 4 00:20 wp-settings.php
-rw-r--r-- 1 xfs xfs 30071 Oct 18 17:36 wp-signup.php
-rw-r--r-- 1 xfs xfs 4620 Oct 23 22:12 wp-trackback.php
-rw-r--r-- 1 xfs xfs 3065 Aug 31 2016 xmlrpc.php
While user in cli container is www-data (just like it is in wordpress container), it cannot create the desired folder:
$ mkdir -p wp-content/uploads/2018/02
mkdir: can't create directory 'wp-content/uploads/': Permission denied
I'm running docker compose 1.18.0 and and docker engine 17.12.0-ce on a mac.
I also created a github issue.

Answer 1

I assume your question is "How do I fix WP-CLI file permission problems using Docker volumes?"
You need to make sure to run wp-cli as the same UID in both containers.
From the command line:
docker run -it --rm \
--volumes-from $container \
--network container:$container \
--user 33:33 \
wordpress:cli core install --path=/var/www/html --url=localhost --title=test --admin_user=test --admin_password=test --admin_email=test#example.com
--user 33:33 is a workaround to run wp-cli with the same UID/GID as www-data in the WordPress container. Problems arise because the containers have different UID/GID for www-data. See https://github.com/docker-library/wordpress/issues/256
You should be able to add user: "33:33" to your docker-compose file as well. See https://github.com/docker/compose/issues/1532