logsley

This is an opinionated Rust logging library.

Features

• Configure the logger with one function call

• Thread scoped variables

• Task scoped variables, with the async feature enabled

• See logging output from tests

• Works with libraries that use log, slog, slog-scope, and slog-scope-futures.

• Logs JSON by default. Set DEV_LOG_FORMAT=full env var to get pretty output in your terminal.

• Adjust logging verbosity of modules with simple string parameter, and override it with the RUST_LOG env var. Example: RUST_LOG=some::spammy::module=warn,my::buggy::module=trace. See slog-envlogger for details.

• Approved by Sir Robin of Logsley:
  

Limitations

• Uses macros

Examples

// You should do logging like this.

let _global_logger_guard =
  logsley::configure("info").unwrap();
logsley::thread_scope("main", || {
  // Log named values:
  logsley::error!("err {}", 1; "x" => 2);
  // {"time_ns":1604899904064111000,
  // "time":"2020-11-08T21:31:44.064-08:00",
  // "module":"opinion",
  // "level":"ERROR",
  // "message":"err 1",
  // "thread":"main",
  // "x":2}
  logsley::warn!("warn {}", 1; "x" => 2);
  logsley::info!("info {}", 1; "x" => 2);
  logsley::debug!("debug {}", 1; "x" => 2);
  logsley::trace!("trace {}", 1; "x" => 2);

  // Log simple messages:
  log::info!("log {}", 1);
  // {"time_ns":1604899904065070000,
  // "time":"2020-11-08T21:31:44.065-08:00",
  // "module":"opinion",
  // "level":"INFO",
  // "message":"log 1",
  // "thread":"main"}

  std::thread::spawn(|| {
    logsley::thread_scope("thread1", || {
      logsley::info!("in thread {}", 1; "x" => 2);
  })})
  .join()
  .unwrap();
  // {"time_ns":1604899904065111000,
  // "time":"2020-11-08T21:31:44.065-08:00",
  // "module":"opinion",
  // "level":"INFO",
  // "message":"in thread 1",
  // "thread":"thread1",
  // "x":2}

  async_std::task::block_on(
    logsley::task_scope("task1", async move {
      logsley::info!(
        "logsley in task {}", 1; "x" => 2);
  }));
  // {"time_ns":1604899904065241000,
  // "time":"2020-11-08T21:31:44.065-08:00",
  // "module":"opinion",
  // "level":"INFO",
  // "message":"logsley in task 1",
  // "task":"task1",
  // "thread":"main",
  // "x":2}

  panic!("uhoh");
  // {"time_ns":1604899904955593000,
  // "time":"2020-11-08T21:31:44.955-08:00",
  // "module":"log_panics",
  // "level":"ERROR",
  // "message":"thread 'main' panicked at 'uhoh': examples/opinion.rs:30\n
  //   0: backtrace::backtrace::libunwind::trace\n
  //             at /.../backtrace-0.3.54/src/backtrace/libunwind.rs:90:5\n
  //      backtrace::backtrace::trace_unsynchronized\n
  //             at /.../backtrace-0.3.54/src/backtrace/mod.rs:66:5\n
  //   1: backtrace::backtrace::trace\n
  //             at /.../backtrace-0.3.54/src/backtrace/mod.rs:53:14\n
  //   2: backtrace::capture::Backtrace::create\n
  //             at /.../backtrace-0.3.54/src/capture.rs:176:9\n
  //   3: backtrace::capture::Backtrace::new\n
  //             at /.../backtrace-0.3.54/src/capture.rs:140:22\n
  //   4: log_panics::init::{{closure}}\n
  //             at /.../log-panics-2.0.0/src/lib.rs:52:25\n
  //   5: std::panicking::rust_panic_with_hook\n
  //             at /.../library/std/src/panicking.rs:581:17\n
  //   6: std::panicking::begin_panic::{{closure}}\n
  //             at /.../library/std/src/panicking.rs:506:9\n
  //   7: std::sys_common::backtrace::__rust_end_short_backtrace\n
  //             at /.../library/std/src/sys_common/backtrace.rs:153:18\n
  //   8: std::panicking::begin_panic\n
  //             at /.../library/std/src/panicking.rs:505:12\n
  //   9: opinion::main::{{closure}}\n
  //             at examples/opinion.rs:30:9\n
  //  10: slog_scope::scope\n
  //             at /.../slog-scope-4.3.0/lib.rs:248:5\n
  //  11: logsley::thread_scope\n
  //             at src/lib.rs:179:5\n
  //  12: opinion::main\n
  //             at examples/opinion.rs:5:5\n
  //  13: core::ops::function::FnOnce::call_once\n
  //             at /.../library/core/src/ops/function.rs:227:5\n
  //  14: std::sys_common::backtrace::__rust_begin_short_backtrace\n
  //             at /.../library/std/src/sys_common/backtrace.rs:137:18\n
  //  15: std::rt::lang_start::{{closure}}\n
  //             at /.../library/std/src/rt.rs:66:18\n
  //  16: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once\n
  //             at /.../library/core/src/ops/function.rs:259:13\n
  //      std::panicking::try::do_call\n
  //             at /.../library/std/src/panicking.rs:381:40\n
  //      std::panicking::try\n
  //             at /.../library/std/src/panicking.rs:345:19\n
  //      std::panic::catch_unwind\n
  //             at /.../library/std/src/panic.rs:382:14\n
  //      std::rt::lang_start_internal\n
  //             at /.../library/std/src/rt.rs:51:25\n
  //  17: std::rt::lang_start\n
  //             at /.../library/std/src/rt.rs:65:5\n
  //  18: _main\n",
  // "thread":"main"}
  });
}

For a runnable example, see examples/opinion.rs.

Set the default log level to info. The program will emit log messages with level info and higher.

let _global_logger_guard = logsley::configure("info");
log::error!("emitted");
log::warn!("emitted");
log::info!("emitted");
log::debug!("not emitted");
log::trace!("not emitted");

Set the default log level to info and set the level for chatty::module1 to warn.

let _global_logger_guard =
    logsley::configure("info,chatty::module1=warn");

Use the environment variable to override default log level. module1 still gets its special log level.

std::env::set_var("RUST_LOG", "debug");
let _global_logger_guard =
    logsley::configure("info,module1=warn");

Use the environment variable to set module1 to debug.

std::env::set_var("RUST_LOG", "module1=debug");
let _global_logger_guard =
    logsley::configure("info");

Documentation

https://docs.rs/logsley

Alternatives

• log
• log-panics
• slog
• slog-async
• slog-envlogger
• slog-json
• slog-scope
• slog-scope-futures
• slog-stdlog
• slog-term

Release Process

1. Edit Cargo.toml and bump version number.
2. Run ./release.sh

Changelog

• v0.1.8 - Add async feature
• v0.1.7 - Bugfix.
• v0.1.6 - Add missing slog reexport.
• v0.1.5 - Rename OutputFormat::JSON to Json to satisfy nightly clippy.
• v0.1.4 - Update docs.
• v0.1.3 - Fix missing slog_scope::logger error
• v0.1.2 - Fix panic in configure_for_test
• v0.1.1 - Make example code fit in crates.io's 60-column code views.
• v0.1.0 - First published version

TODO

• DONE - Try to make this crate comply with the Rust API Guidelines.
• DONE - Include Readme.md info in the crate's docs.
• DONE - Make the repo public
• DONE - Set up continuous integration tests and banner.
  • https://gitlab.com/mattdark/firebase-example/blob/master/.gitlab-ci.yml
  • https://medium.com/astraol/optimizing-ci-cd-pipeline-for-rust-projects-gitlab-docker-98df64ae3bc4
  • https://hub.docker.com/_/rust
• DONE - Add some documentation tests
  • https://doc.rust-lang.org/rustdoc/documentation-tests.html
  • https://doc.rust-lang.org/stable/rust-by-example/testing/doc_testing.html
• DONE - Publish to creates.io
• DONE - Read through https://crate-ci.github.io/index.html
• DONE - Add and update a changelog
  • Update it manually
  • https://crate-ci.github.io/release/changelog.html
• Get a code review from an experienced rustacean
• Add features: threads, futures, term

License: Apache-2.0