fast_log
A high-performance asynchronous logging library for Rust built on crossbeam channels with appender-per-thread architecture.
What is fast_log?
fast_log is a high-performance asynchronous logging library for Rust. It solves the problem of logging overhead in performance-critical applications by using a multi-channel architecture with batch writing and dedicated appenders per thread.
Rust developers building high-performance applications where logging speed and low overhead are critical, such as servers, real-time systems, and data processing pipelines.
Developers choose fast_log for its extreme performance, safe Rust implementation, and flexible features like log rotation, compression, and custom appenders without sacrificing speed.
Overview
Rust async log High-performance asynchronous logging
Use Cases
Best For
- High-performance Rust servers needing minimal logging overhead
- Real-time applications requiring asynchronous log processing
- Systems needing log rotation by date, size, or duration
- Applications requiring compressed log storage
- Projects prioritizing 100% safe Rust code
- Distributed systems with parallel logging requirements
Not Ideal For
- Applications requiring immediate log persistence for audit trails or crash recovery
- Teams wanting zero-configuration logging with extensive third-party integrations like Datadog
- Projects where structured logging in formats like JSON is a primary requirement out of the box
Pros & Cons
Pros
Benchmarks show logging operations as low as 85 nanoseconds per iteration using crossbeam channels and batch writing, minimizing overhead.
Enforces 100% safe Rust with #![forbid(unsafe_code)], eliminating memory safety risks in production environments.
Supports log rotation by date, size, or duration with built-in compression options like ZIP and LZ4, as shown in the file_split examples.
Uses dedicated appenders per thread to reduce contention, improving throughput in multi-threaded applications.
Allows implementing the LogAppender trait for custom destinations, demonstrated in the custom log example.
Cons
Requires manual tuning of parameters like chan_len for optimal performance, which can be complex and error-prone compared to simpler libraries.
Logs are batched and processed asynchronously, causing a delay before persistence that might not suit real-time monitoring or debugging needs.
Being performance-focused, it lacks the wide range of plugins and third-party tool integrations found in more established logging crates.
Frequently Asked Questions
Related Projects
tracingApplication level tracing for Rust.
logLogging implementation for Rust
slogStructured, contextual, extensible, composable logging for Rust
log4rsA highly configurable logging framework for Rust
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