lean-log 0.1.0

A tiny, zero-overhead logging framework
Documentation 
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# lean-log

A **zero-overhead** logging framework for Rust with compile-time level filtering, structured logging, and minimal runtime cost.

## Add to your project

```toml
[dependencies]
lean-log = "0.1"
```

## Usage

```rust
use lean_log::{info, debug, warn, error, Level};

fn main() {
    lean_log::init(); // reads RUST_LOG env var, defaults to Info

    info!("server started");
    info!("listening on port {}", 8080);

    let path = "/api/health";
    debug!("request received"; path = path);

    warn!("retrying connection"; attempt = 3);
    error!("disk full"; used_bytes = 1024_u64);
}
```

Output goes to **stderr** with ANSI colour by default. To write to a file instead:

```rust
lean_log::set_file_logging("app.log").unwrap();
// or append:
lean_log::append_file_logging("app.log").unwrap();
```

## Log levels

`Off` < `Error` < `Warn` < `Notice` < `Info` < `Debug` < `Trace`

Set at runtime with `lean_log::set_level(Level::Debug)` or via the `RUST_LOG` environment variable.

## Compile-time level cap (features)

Enable only the levels you need to eliminate call sites entirely at compile time:

| Feature                 | Levels compiled in       |
| ----------------------- | ------------------------ |
| `max_error`             | Error only               |
| `max_warn`              | Error, Warn              |
| `max_notice`            | + Notice                 |
| `max_info`              | + Info                   |
| `max_debug` *(default)* | + Debug                  |
| `max_trace`             | all levels               |
| `disabled`              | none (all calls removed) |

## Structured fields

Append key=value fields after a `;` separator:

```rust
info!("user logged in"; user_id = 42, %role);   // Display
debug!("parsed value"; ?result);                 // Debug
```

## License

MIT