spdlog-rs

A fast and combinable Rust logging crate, inspired by the C++ logging library spdlog.

Features

• Very fast (see Benchmarks below).
• Various log targets:
  • Standard streams with optional colors.
  • Files.
  • Rotating log files by file size.
  • Rotating log files hourly.
  • Rotating log files daily.
  • ... (more targets are implementing, PRs are welcome)
  • Extendable with custom log targets.
• Compatible with log crate (optional).
• Asynchronous support.
• Configured via environment variable.
• Custom formatting.
• Log filtering - log levels can be modified in runtime as well as in compile time.

Getting started

Add this to Cargo.toml:

[dependencies]
spdlog-rs = "0.2"

The documentation of this crate is hosted on docs.rs, and you can find examples under ./examples directory.

If you have any questions or need help while using this crate, feel free to open a discussion. For feature requests or bug reports, please open an issue.

Supported Rust Versions

The current minimum supported Rust version is 1.56.

spdlog-rs is built against the latest Rust stable release, it is not guaranteed to build on Rust versions earlier than the minimum supported version.

spdlog-rs follows the compiler support policy that the latest stable version and the 3 most recent minor versions before that are always supported. For example, if the current latest Rust stable version is 1.61, the minimum supported version will not be increased past 1.58. Increasing the minimum supported version is not considered a semver breaking change as long as it complies with this policy.

Benchmarks

Run cargo +nightly bench --features multi-thread in the root directory of this repository for benchmarking.

The following results are generated with Windows 10 64 bit and Intel i9-10900KF CPU @ 3.70GHz.

Disclaimer, I'm not entirely familiar with using the other Rust crates below, so if you find a bug or something worth improving in the benchmark code, feel free to open an issue to let me know.

spdlog-rs (0.1.0)

Default features

test bench_file               ... bench:         376 ns/iter (+/- 12)
test bench_level_off          ... bench:           1 ns/iter (+/- 0)
test bench_rotating_daily     ... bench:         380 ns/iter (+/- 12)
test bench_rotating_file_size ... bench:         379 ns/iter (+/- 50)

Enable flexible-string feature

test bench_file               ... bench:         166 ns/iter (+/- 10)
test bench_level_off          ... bench:           1 ns/iter (+/- 0)
test bench_rotating_daily     ... bench:         172 ns/iter (+/- 7)
test bench_rotating_file_size ... bench:         176 ns/iter (+/- 20)

Compare with slog (2.7.0)

test bench_file               ... bench:         469 ns/iter (+/- 19)
test bench_level_off          ... bench:           2 ns/iter (+/- 0)
test bench_rotating_daily     ... bench:         unavailable
test bench_rotating_file_size ... bench:         480 ns/iter (+/- 13)

Compare with flexi_logger (0.22.2)

test bench_file               ... bench:         673 ns/iter (+/- 11)
test bench_level_off          ... bench:           0 ns/iter (+/- 0)
test bench_rotating_daily     ... bench:         746 ns/iter (+/- 40)
test bench_rotating_file_size ... bench:         676 ns/iter (+/- 38)

Compare with log4rs (1.0.0)

test bench_file               ... bench:       3,769 ns/iter (+/- 95)
test bench_level_off          ... bench:           0 ns/iter (+/- 0)
test bench_rotating_daily     ... bench:         unavailable
test bench_rotating_file_size ... bench:       3,773 ns/iter (+/- 117)

Compare with fern (0.6.0)

test bench_file               ... bench:       3,687 ns/iter (+/- 101)
test bench_level_off          ... bench:         unavailable
test bench_rotating_daily     ... bench:         unavailable
test bench_rotating_file_size ... bench:         unavailable

Compare with C++ spdlog

spdlog-rs (0.1.0)

Default features (corresponds to C++ spdlog using standard <format>)

[info] **********************************************************************
[info] Multi threaded: 1 threads, 250000 messages
[info] **********************************************************************
[info] basic_mt                       Elapsed: 0.13 secs          1940870/sec
[info] rotating_mt                    Elapsed: 0.13 secs          1894612/sec
[info] daily_mt                       Elapsed: 0.13 secs          1920024/sec
[info] level-off                      Elapsed: 0.00 secs        444919024/sec
[info] **********************************************************************
[info] Multi threaded: 4 threads, 250000 messages
[info] **********************************************************************
[info] basic_mt                       Elapsed: 0.14 secs          1825379/sec
[info] rotating_mt                    Elapsed: 0.14 secs          1845651/sec
[info] daily_mt                       Elapsed: 0.13 secs          1854885/sec
[info] level-off                      Elapsed: 0.00 secs        485625485/sec

Enable flexible-string feature (corresponds to C++ spdlog using fmt library)

[info] **********************************************************************
[info] Multi threaded: 1 threads, 250000 messages
[info] **********************************************************************
[info] basic_mt                       Elapsed: 0.08 secs          3003511/sec
[info] rotating_mt                    Elapsed: 0.08 secs          3006090/sec
[info] daily_mt                       Elapsed: 0.08 secs          3032813/sec
[info] level-off                      Elapsed: 0.00 secs        484871993/sec
[info] **********************************************************************
[info] Multi threaded: 4 threads, 250000 messages
[info] **********************************************************************
[info] basic_mt                       Elapsed: 0.06 secs          4266393/sec
[info] rotating_mt                    Elapsed: 0.06 secs          4271496/sec
[info] daily_mt                       Elapsed: 0.06 secs          4164993/sec
[info] level-off                      Elapsed: 0.00 secs        462962962/sec

C++ spdlog (4cfdc8c)

Using standard <format> (compiled with cmake -G "Visual Studio 16 2019" -A x64 -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON -DSPDLOG_BUILD_BENCH=ON -DSPDLOG_BUILD_EXAMPLE=OFF -DSPDLOG_USE_STD_FORMAT=ON)

[info] **************************************************************
[info] Multi threaded: 1 threads, 250,000 messages
[info] **************************************************************
[info] basic_mt                       Elapsed: 0.15 secs        1,654,676/sec
[info] rotating_mt                    Elapsed: 0.16 secs        1,576,156/sec
[info] daily_mt                       Elapsed: 0.15 secs        1,671,424/sec
[info] level-off                      Elapsed: 0.00 secs      132,597,857/sec
[info] **************************************************************
[info] Multi threaded: 4 threads, 250,000 messages
[info] **************************************************************
[info] basic_mt                       Elapsed: 0.26 secs          965,885/sec
[info] rotating_mt                    Elapsed: 0.26 secs          964,368/sec
[info] daily_mt                       Elapsed: 0.25 secs          981,449/sec
[info] level-off                      Elapsed: 0.00 secs      135,310,673/sec

Using fmt library (compiled with cmake -G "Visual Studio 16 2019" -A x64 -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=20 -DCMAKE_CXX_STANDARD_REQUIRED=ON -DSPDLOG_BUILD_BENCH=ON -DSPDLOG_BUILD_EXAMPLE=OFF)

[info] **************************************************************
[info] Multi threaded: 1 threads, 250,000 messages
[info] **************************************************************
[info] basic_mt                       Elapsed: 0.06 secs        3,917,304/sec
[info] rotating_mt                    Elapsed: 0.06 secs        3,942,073/sec
[info] daily_mt                       Elapsed: 0.07 secs        3,784,707/sec
[info] level-off                      Elapsed: 0.00 secs      148,174,490/sec
[info] **************************************************************
[info] Multi threaded: 4 threads, 250,000 messages
[info] **************************************************************
[info] basic_mt                       Elapsed: 0.11 secs        2,356,303/sec
[info] rotating_mt                    Elapsed: 0.12 secs        2,138,911/sec
[info] daily_mt                       Elapsed: 0.12 secs        2,163,183/sec
[info] level-off                      Elapsed: 0.00 secs      148,060,408/sec

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (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, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.