# Official Docker image

This is an official Docker image for [sidekiq-prometheus-exporter](https://github.com/Strech/sidekiq-prometheus-exporter)
gem.

It combines some approaches which were already published as images by other
devs and at the same time brings more flexibility for the stock configuration
and applies recommended Docker best practices.

:warning: The Docker image currently supports **only** standards metrics.

## Supported ENVs

Required

- `REDIS_URL` - [RFC 3986 generic URI][rfc3986], exclusive with `REDIS_HOST`
- `REDIS_HOST` - a Redis host, exclusive with `REDIS_URL` (default: `localhost`)

Optional

- `REDIS_PORT` - a Redis port (default: `6379`)
- `REDIS_PASSWORD` - a Redis password (if you need one)
- `REDIS_DB_NUMBER` - a Redis database number (default: `0`)
- `REDIS_NAMESPACE` - a Redis [namespace][namespace] name (if you have separated sidekiq)
- `REDIS_SENTINELS` - a list of comma separated Redis urls (like `REDIS_URL`, but for sentinels)
- `REDIS_SENTINEL_ROLE` - a role within the [sentinel][sentinel] to connect (default: `master`)

:bulb: Note, that `REDIS_URL` and `REDIS_HOST` are exclusive. Since `REDIS_HOST` is more
atomic value it will be checked after `REDIS_URL`.

:bulb: `REDIS_SENTINELS` will be parsed with `URI`, because of that it's
mandatory for them to be formatted with protocol `redis://...`.

## Examples

If you don't have a running Redis instance, you can quickly spin an empty to
practice.

```bash
$ docker run -d --rm --name redis-instance redis
```

and then run an exporter

```bash
$ docker run -it --rm \
             --link redis-instance \
             -p 9292:9292 \
             -e REDIS_URL=redis://redis-instance \
             strech/sidekiq-prometheus-exporter
```

[rfc3986]: https://www.iana.org/assignments/uri-schemes/prov/redis
[namespace]: https://github.com/resque/redis-namespace
[sentinel]: https://github.com/redis/redis-rb/tree/v4.1.3#sentinel-support