Crate tracing_unwrap

This crate provides .unwrap_or_log() and .expect_or_log() methods on Result and Option types that log failed unwraps to a tracing::Subscriber. This is useful when, for example, you are logging to syslog or a database, and you want your unwrap failures to show up there instead of being printed to stderr.

Its API aims to mirror Rust’s std — see all the supported methods below. Failed unwraps are logged at a level of ERROR.

Usage

Add the following to your Cargo.toml:

tracing-unwrap = "1.0"

Next, bring the ResultExt and/or OptionExt traits into scope, and make use of the new logging methods.

use tracing_unwrap::ResultExt;

tracing_subscriber::fmt().init();
let not_great: Result<(), _> = Result::Err("not terrible");

// Logs the failed unwrap and panics
not_great.unwrap_or_log();

Methods

std method	tracing-unwrap form	trait
Result::ok()	Result::ok_or_log()	ResultExt
Result::unwrap()	Result::unwrap_or_log()	ResultExt
Result::expect(msg)	Result::expect_or_log(msg)	ResultExt
Result::unwrap_err()	Result::unwrap_err_or_log()	ResultExt
Result::expect_err(msg)	Result::expect_err_or_log(msg)	ResultExt
Option::unwrap()	Option::unwrap_or_log()	OptionExt
Option::expect(msg)	Option::expect_or_log(msg)	OptionExt
Option::unwrap_none()†	Option::unwrap_none_or_log()	OptionExt
Option::expect_none(msg)†	Option::expect_none_or_log(msg)	OptionExt

†: no longer in std, see rust-lang/rust#62633

Features

• panic-quiet: causes failed unwraps to panic with an empty message.
  This feature is enabled by default — if you’d like the unwrap error message to also show in the panic message, disable default features in your Cargo.toml as follows:
  tracing-unwrap = { version = "1.0", default-features = false }

• log-location: calls std::panic::Location::caller() to determine the location of a failed unwrap.

Traits

• OptionExt
  Extension trait for Option types.
• ResultExt
  Extension trait for Result types.