f515e9d35c
## Motivation This PR attempts to solve #1630 by introducing `err(Debug)` meta to `intrument` attribute macro. As `err` meta causes the error (`e`) returned by instrumented function to be passed to `tracing::error!(error = %e)` i.e. makes it use the `Display` implementation of `e`, the newly added `err(Debug)` makes expands to `tracing::error!(error = ?e)` which makes the `error!` macro to use `Debug` implementation for `e`. `err` and `err(Debug)` are mutually exclusive, adding both will create a compilation error. `err(Display)` is also supported to specify `Display` explicitly. As tried to describe, for some types implementing `Error` it might be more suitable to use `Debug` implementation as in the case of `eyre::Result`. This frees us to manually go over the error chain and print them all, so that `instrument` attribute macro would do it for us. ## Solution - Added a custom keyword `err(Debug)` similar to `err`, - Add `err(Debug)` field to `InstrumentArgs`, - Add parsing for `err(Debug)` arg and check for conflicts with `err`, - Generate `tracing::error!(error = ?e)` when `err(Debug)` is `true` and `tracing::error!(error = %e)` when `err(Display)` or `err` is `true`, - Interpolate generated `err_block` into `Err` branches in both async and sync return positions, if `err` or `err(Debug)` is `true`.
tracing-attributes
Macro attributes for application-level tracing.
Overview
tracing is a framework for instrumenting Rust programs to collect
structured, event-based diagnostic information. This crate provides the
#[instrument] attribute for automatically instrumenting functions using
tracing.
Note that this macro is also re-exported by the main tracing crate.
Compiler support: requires rustc 1.42+
Usage
First, add this to your Cargo.toml:
[dependencies]
tracing-attributes = "0.1.18"
This crate provides the #[instrument] attribute for instrumenting a function
with a tracing span. For example:
use tracing_attributes::instrument;
#[instrument]
pub fn my_function(my_arg: usize) {
// ...
}
Supported Rust Versions
Tracing is built against the latest stable release. The minimum supported version is 1.42. The current Tracing version is not guaranteed to build on Rust versions earlier than the minimum supported version.
Tracing follows the same compiler support policies as the rest of the Tokio project. The current stable Rust compiler and the three most recent minor versions before it will always be supported. For example, if the current stable compiler version is 1.45, the minimum supported version will not be increased past 1.42, three minor versions prior. Increasing the minimum supported compiler version is not considered a semver breaking change as long as doing so complies with this policy.
License
This project is licensed under the MIT license.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Tokio by you, shall be licensed as MIT, without any additional terms or conditions.