| commit | 28e0c72e0380786ead30eaa3d19ca85899ae5893 | [log] [tgz] |
|---|---|---|
| author | Marcin Radomski <[email protected]> | Thu Aug 17 16:11:56 2023 +0000 |
| committer | Marcin Radomski <[email protected]> | Wed Aug 23 15:11:54 2023 +0000 |
| tree | bc821a5b1a090001abcdc07eb801ec9ddc199f5a | |
| parent | 1a36a6a8e10d14dd4c7a6a3d33ff7e7e654cc6e1 [diff] |
Enable default-initializing liblog_rust to write to logcat on Android Add default_log_impl cfg that, when enabled, makes `liblog_rust` use `android_logger` instead of `NopLogger` by default. This makes it possible to embed android_logger as mod inside liblog_rust crate, so that AndroidLogger can be used as default logger instead of a NopLogger. Changing that default prevents dropping logs when the logger is uninitialized. This can happen by accident when an application doesn't intialize the logger in all linker namespaces it pulls libraries from. See discussion at b/294216366#comment7. Bug: 275290559 Test: compile test app from aosp/2717614 Test: run it on a Cuttlefish device Test: observe logcat logs on all level from FFI call Test: observe all logs on non-FFI call without initializing the logger Test: observe set log filter applying only to non-FFI call Change-Id: I04dd334c66e5a2be8cfb19e87be3afb9146e5aa6
A Rust library providing a lightweight logging facade.
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.
rustc1.31.0+
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.
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 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:
log to initialize in your libraries.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.
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"); } } } }