# Objective
In my library,
[`bevy_dev_console`](https://github.com/doonv/bevy_dev_console) I need
access to `App` within `LogPlugin::update_subscriber` in order to
communicate with the `App` from my custom `Layer`.
## Solution
Give access to `App`.
---
## Changelog
- Added access to `App` within `LogPlugin::update_subscriber`
## Migration Guide
`LogPlugin::update_subscriber` now has a `&mut App` parameter. If you
don't need access to `App`, you can ignore the parameter with an
underscore (`_`).
```diff,rust
- fn update_subscriber(subscriber: BoxedSubscriber) -> BoxedSubscriber {
+ fn update_subscriber(_: &mut App, subscriber: BoxedSubscriber) -> BoxedSubscriber {
Box::new(subscriber.with(CustomLayer))
}
```
# Objective
This PR is heavily inspired by
https://github.com/bevyengine/bevy/pull/7682
It aims to solve the same problem: allowing the user to extend the
tracing subscriber with extra layers.
(in my case, I'd like to use `use
metrics_tracing_context::{MetricsLayer, TracingContextLayer};`)
## Solution
I'm proposing a different api where the user has the opportunity to take
the existing `subscriber` and apply any transformations on it.
---
## Changelog
- Added a `update_subscriber` option on the `LogPlugin` that lets the
user modify the `subscriber` (for example to extend it with more tracing
`Layers`
## Migration Guide
> This section is optional. If there are no breaking changes, you can
delete this section.
- Added a new field `update_subscriber` in the `LogPlugin`
---------
Co-authored-by: Charles Bournhonesque <cbournhonesque@snapchat.com>
