We run Dokku, and therefore dokku redis, in its own Docker container.
In order to make this work we map a path from the host into the
container as `/var/lib/dokku/services/redis`. Unfortunately the path
on the host is user-configurable, and generally _won't_ be the same
as the path in the container. This means that when we run `docker`
commands (e.g. to spin up Redis containers), the directory used for
bind mounts (the `-v` option) needs to be different.
This commit allows us to do this, but keeps the existing behaviour
(the redis root for Docker binds is the same as the redis root for
other uses) by default.
This change makes password authentication required
for redis usage, and removes anonymous access. Users
will need to change their underlying clients to enable
writing the auth token for authenticating, otherwise
requests will fail.
This is a non-optional change, and improves security
for users who wish to expose their redis installations
outside of their network.
Previously we were exporting `REDIS_URL` via the docker-args* hooks.
This seems to confuse our users (since the env var is not displayed
when calling `dokku config`) and in some cases it also seems that the
env var is not correctly set.
Another problem is if several services are linked to the same app and
if they are exporting `REDIS_URL` as well. Then we don’t know what
will be set.
To resolve theses issues, this patch changes the way we manage the env
vars. We use standard dokku commands (`config` and `docker-options`) so
config is set on the linked application and can be reviewed by the user
easily.
We also handle the case where `REDIS_URL` is already set on the
linked application. When it’s the case, we automatically generate
another env var based on the following pattern: DOKKU_<service
name>_<random unused color>_URL. For example, this can give:
DOKKU_REDIS_BLACK_URL.
Since naming is now handled automatically, the `alias` command has been
removed. If the user wants to set a different env var on her app, it’s
just a matter of using `dokku config:set` and pasting the wanted value.
IP in DSN has been removed in favor of host name exported by docker in
the container. This is more robust and simpler since the IP can change
but the name will remain the same if the service container restarts for
instance.
With all those changes, a new command has been introduced: `promote`.
The goal of this command is to easily set a service as the primary one
when several are linked to an app. (see README for an example)
