Merge pull request #984 from SKoschnicke/patch-1

Added WORDPRESS_DB_PASSWORD_FILE to readme

wordpress/content.md

@@ -38,6 +38,16 @@ $ docker run --name some-%%REPO%% -e WORDPRESS_DB_HOST=10.1.2.3:3306 \
     -e WORDPRESS_DB_USER=... -e WORDPRESS_DB_PASSWORD=... -d %%REPO%%
 ```
 
+## Docker Secrets
+
+As an alternative to passing sensitive information via environment variables, `_FILE` may be appended to the previously listed environment variables, causing the initialization script to load the values for those variables from files present in the container. In particular, this can be used to load passwords from Docker secrets stored in `/run/secrets/<secret_name>` files. For example:
+
+```console
+$ docker run --name some-wordpress -e WORDPRESS_DB_PASSWORD_FILE=/run/secrets/mysql-root ... -d %%IMAGE%%:tag
+```
+
+Currently, this is supported for `WORDPRESS_DB_HOST`, `WORDPRESS_DB_USER`, `WORDPRESS_DB_PASSWORD`, `WORDPRESS_DB_NAME`, `WORDPRESS_AUTH_KEY`, `WORDPRESS_SECURE_AUTH_KEY`, `WORDPRESS_LOGGED_IN_KEY`, `WORDPRESS_NONCE_KEY`, `WORDPRESS_AUTH_SALT`, `WORDPRESS_SECURE_AUTH_SALT`, `WORDPRESS_LOGGED_IN_SALT`, `WORDPRESS_NONCE_SALT`, `WORDPRESS_TABLE_PREFIX`, and `WORDPRESS_DEBUG`.
+
 ## %%STACK%%
 
 Run `docker stack deploy -c stack.yml %%REPO%%` (or `docker-compose -f stack.yml up`), wait for it to initialize completely, and visit `http://swarm-ip:8080`, `http://localhost:8080`, or `http://host-ip:8080` (as appropriate).