bevy/examples/app/log_layers.rs
Charles Bournhonesque 8c6d9b8103
Add support for updating the tracing subscriber in LogPlugin (#10822)
# 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>
2024-01-15 15:26:13 +00:00

47 lines
1.4 KiB
Rust

//! This example illustrates how to add custom log layers in bevy.
use bevy::{
log::tracing_subscriber::{layer::SubscriberExt, Layer},
log::BoxedSubscriber,
prelude::*,
utils::tracing::Subscriber,
};
struct CustomLayer;
impl<S: Subscriber> Layer<S> for CustomLayer {
fn on_event(
&self,
event: &bevy::utils::tracing::Event<'_>,
_ctx: bevy::log::tracing_subscriber::layer::Context<'_, S>,
) {
println!("Got event!");
println!(" level={:?}", event.metadata().level());
println!(" target={:?}", event.metadata().target());
println!(" name={:?}", event.metadata().name());
}
}
fn update_subscriber(subscriber: BoxedSubscriber) -> BoxedSubscriber {
Box::new(subscriber.with(CustomLayer))
}
fn main() {
App::new()
.add_plugins(DefaultPlugins.set(bevy::log::LogPlugin {
update_subscriber: Some(update_subscriber),
..default()
}))
.add_systems(Update, log_system)
.run();
}
fn log_system() {
// here is how you write new logs at each "log level" (in "most import" to
// "least important" order)
error!("something failed");
warn!("something bad happened that isn't a failure, but thats worth calling out");
info!("helpful information that is worth printing by default");
debug!("helpful for debugging");
trace!("very noisy");
}