Crate minimal_logger 

Minimal-resource logger for Rust applications.

minimal_logger provides a small, thread-buffered logger with optional file output, auto flush, and platform-aware log rotation.

Example

use log::{error, info};

fn main() {
    minimal_logger::init().expect("failed to initialise logger");
    info!("application started");
    error!("shutdown due to error");
    minimal_logger::shutdown();
}

Rotation detection

Each thread-local BufWriter<FileWriter> holds an Arc<LogFile> inside FileWriter. On every log call, load_full() returns the current Arc<LogFile>. If Arc::ptr_eq fails, a rotation has occurred:

1. Flush old BufWriter → drains remaining bytes to old file.
2. Replace with new BufWriter::with_capacity(capacity, FileWriter(new_arc)). No separate reopen flag check is needed inside write_record.

Flush model

Trigger	Mechanism
Buffer full	BufWriter flushes automatically when internal
	buffer capacity is reached
Periodic	Background thread sets FLUSH_FLAG; next log call
	calls bw.flush()
Thread exit	BufWriter::drop() calls flush() automatically
Explicit	shutdown() / Log::flush() calls bw.flush()

Environment variables

Variable	Default	Description
RUST_LOG	info	Level + per-target filters
RUST_LOG_FILE	stderr	Absolute path to log file
RUST_LOG_BUFFER_SIZE	4096	Per-thread BufWriter capacity
RUST_LOG_FLUSH_MS	1000	Periodic flush interval (ms)
RUST_LOG_FORMAT	"{timestamp} [{level:<5}] T[{thread_name}] [{file}:{line}] {args}"	Log message format template (timestamp is fixed 6-digit microseconds)

Supported format fields: timestamp, level, thread_name, target, module_path, file, line, args.

Structs

MinimalLogger

Functions

init

Initialise the logger and start the background flush thread. Call once at program startup before any log macros are used.

shutdown

Flush the calling thread’s BufWriter to the kernel.