# log4rs
[](https://docs.rs/log4rs)
[](https://crates.io/crates/log4rs)
[](#license)
[](https://github.com/estk/log4rs#rust-version-requirements)
log4rs is a highly configurable logging framework modeled after Java's Logback
and log4j libraries.
### Warning
If you are using the file rotation in your configuration there is a known substantial performance issue so listen up!
By default the `gzip` feature is enabled and when rolling files it will zip log archives automatically. This is a problem
when the log archives are large as the zip happens in the main thread and will halt the process while the zip is completed.
Be advised that the `gzip` feature will be removed from default features as of `1.0`.
The methods to mitigate this are as follows.
1. Use the `background_rotation` feature which spawns an os thread to do the compression.
1. Disable the `gzip` feature with `--no-default-features`.
1. Ensure the archives are small enough that the compression time is acceptable.
For more information see the PR that added [`background_rotation`](https://github.com/estk/log4rs/pull/117).
## Quick Start
log4rs.yaml:
```yaml
refresh_rate: 30 seconds
appenders:
stdout:
kind: console
requests:
kind: file
path: "log/requests.log"
encoder:
pattern: "{d} - {m}{n}"
root:
level: warn
appenders:
- stdout
loggers:
app::backend::db:
level: info
app::requests:
level: info
appenders:
- requests
additive: false
```
lib.rs:
```rust
use log::{error, info, warn};
use log4rs;
fn main() {
log4rs::init_file("config/log4rs.yaml", Default::default()).unwrap();
info!("booting up");
// ...
}
```
## Rust Version Requirements
1.46
## Building for Dev
* Run the tests: `cargo test --all-features`
* Run the tests for windows with [cross](https://github.com/rust-embedded/cross): `cross test --target x86_64-pc-windows-gn`
* Run the tests for all individual features: `./test.sh`
* Run the tests for all individual features for windows with [cross](https://github.com/rust-embedded/cross): `./test.sh win`
## License
Licensed under either of
* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you shall be dual licensed as above, without any
additional terms or conditions.