4556cb3dc2
## Motivation Currently, `tracing-subscriber`'s `Registry` type doesn't document how span IDs are generated, or the uniqueness guarantees for span IDs. This can cause confusion for users trying to implement `Subscribe`rs and other code that interacts with the `Registry`'s generated span IDs. ## Solution This branch adds a new documentation section to the `Registry` docs describing how IDs are generated and when they are guaranteed to be unique. In particular, the new section explicitly states that the registry's IDs will not uniquely identify a span historically, because IDs may be reused when a span has closed, and that the registry's `tracing` span IDs should not be used as span IDs in a distributed tracing system. While I was working on these docs, I also fixed a link on adding subscribers to a registry that went to a specific method on `FmtSubscriber`, rather than to the more general docs on how subscribers are composed with collectors. Thanks to @Folyd for suggesting this docs improvement! Signed-off-by: Eliza Weisman <eliza@buoyant.io> Co-authored-by: David Barsky <me@davidbarsky.com>
tracing-subscriber
Utilities for implementing and composing tracing subscribers.
Compiler support: requires rustc 1.42+
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 Tracing by you, shall be licensed as MIT, without any additional terms or conditions.