feat(redis): add ansible role

roles/redis/README.md

@@ -0,0 +1,47 @@
+# `finallycoffee.databases.redis` ansible role
+
+Redis is the self-proclaimed world's fastest data platform for caching,
+vector search and NoSQL databases. Since version 7.2.4, it is no longer
+considered "Free and open source software" (FOSS), with redis switching
+their license to the "Serverside public license" (SSPL).
+
+Setting the `redis_version` to higher than `7.2.4` means you will deploy
+the SSPL-licensed version to redis.
+
+## Configuration
+
+All container-related options to the `docker_container` ansible module
+are available under the `redis_container_*` namespace, for example use
+`redis_container_ports: [ '127.0.0.1:6379:6370/tcp' ]` to map the
+containers port 6379 to the docker host.
+
+Redis-related config options are either available in the `redis_config_*`
+namespace or can be specified by setting them as a dictionary in
+`redis_config`
+
+### Authentication and authorization
+
+Redis ACL can be specified as an array in the `redis_config_user` variable
+ - see [the redis documentation](https://github.com/redis/redis/blob/unstable/redis.conf#L869)
+for the format. Per default, the `default` user is able to connect without
+any password. To require a password and use a different user, override
+the variable, for example `redis_config_user: [ 'username on +@all -DEBUG ~* >secret' ]`.
+
+## Redis on a unix socket
+
+To make redis available on a unix socket, a directory must be supplied in which the
+socket lives:
+```yaml
+redis_container_socket: /var/run/redis.sock
+redis_container_volumes:
+  - "/path/to/socket/on/host/redis.sock:{{ redis_container_socket }}:z"
+redis_config_unixsocket: "{{ redis_container_socket }}"
+```
+
+## Container specific information
+
+Redis publishes their official container image in both a debian-based and an
+alpine-based variant. Which image should be used can be configured in
+`redis_container_image_flavour`, which defaults to `alpine`, which is smaller
+in size but also includes less related / debugging tools. To use the debian-
+based image, unset the flavour using `redis_container_image_flavour: ~`.