Google Git
Sign in
android / platform / external / rust / crates / log / refs/heads/emu-35-1-release
commitab880eab170fc1d0e0fb41f886289410959f33b3[log] [tgz]
authorAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Thu Mar 14 18:11:45 2024 +0000
committerAndroid Build Coastguard Worker <android-build-coastguard-worker@google.com>Thu Mar 14 18:11:45 2024 +0000
treec414d08629a964e9414ece6bdfb52fa506ea6d6b
parent57b584d56887940773a8cbbc9cfb8b8a1d2c1a8b [diff]
parent48f97f3015c6f7110719fdd2f335c0f2bb547d5a [diff]
Snap for 11574415 from 48f97f3015c6f7110719fdd2f335c0f2bb547d5a to emu-35-1-release

Change-Id: I81b3a28db23f4caa2fec51eeb7dd4134286847b0
tree: c414d08629a964e9414ece6bdfb52fa506ea6d6b
  1. .github/
  2. benches/
  3. patches/
  4. src/
  5. LICENSE ⇨ LICENSE-APACHE
  6. .cargo_vcs_info.json
  7. .gitignore
  8. Android.bp
  9. android_impl.bp
  10. build.rs
  11. Cargo.toml
  12. Cargo.toml.orig
  13. cargo2rulesmk.json
  14. cargo_embargo.json
  15. CHANGELOG.md
  16. CleanSpec.mk
  17. LICENSE-APACHE
  18. LICENSE-MIT
  19. METADATA
  20. MODULE_LICENSE_APACHE2
  21. OWNERS
  22. README.md
  23. rules.mk
  24. TEST_MAPPING
  25. triagebot.toml
README.md

log

A Rust library providing a lightweight logging facade.

Build status Latest version Documentation License

A logging facade provides a single logging API that abstracts over the actual logging implementation. Libraries can use the logging API provided by this crate, and the consumer of those libraries can choose the logging implementation that is most suitable for its use case.

Minimum supported rustc

1.31.0+

This version is explicitly tested in CI and may be bumped in any release as needed. Maintaining compatibility with older compilers is a priority though, so the bar for bumping the minimum supported version is set very high. Any changes to the supported minimum version will be called out in the release notes.

Usage

In libraries

Libraries should link only to the log crate, and use the provided macros to log whatever information will be useful to downstream consumers:

[dependencies]
log = "0.4"

use log::{info, trace, warn};

pub fn shave_the_yak(yak: &mut Yak) {
    trace!("Commencing yak shaving");

    loop {
        match find_a_razor() {
            Ok(razor) => {
                info!("Razor located: {}", razor);
                yak.shave(razor);
                break;
            }
            Err(err) => {
                warn!("Unable to locate a razor: {}, retrying", err);
            }
        }
    }
}

In executables

In order to produce log output, executables have to use a logger implementation compatible with the facade. There are many available implementations to choose from, here are some of the most popular ones:

Executables should choose a logger implementation and initialize it early in the runtime of the program. Logger implementations will typically include a function to do this. Any log messages generated before the logger is initialized will be ignored.

The executable itself may use the log crate to log as well.

Structured logging

If you enable the kv_unstable feature, you can associate structured data with your log records:

use log::{info, trace, warn, as_serde, as_error};

pub fn shave_the_yak(yak: &mut Yak) {
    trace!(target = "yak_events", yak = as_serde!(yak); "Commencing yak shaving");

    loop {
        match find_a_razor() {
            Ok(razor) => {
                info!(razor = razor; "Razor located");
                yak.shave(razor);
                break;
            }
            Err(err) => {
                warn!(err = as_error!(err); "Unable to locate a razor, retrying");
            }
        }
    }
}