![Tracing — Structured, application-level diagnostics][splash] [splash]: https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/splash.svg # tracing-serde An adapter for serializing [`tracing`] types using [`serde`]. [![Documentation][docs-badge]][docs-url] [![Documentation (master)][docs-master-badge]][docs-master-url] [docs-badge]: https://docs.rs/tracing-serde/badge.svg [docs-url]: https://docs.rs/tracing-serde [docs-master-badge]: https://img.shields.io/badge/docs-master-blue [docs-master-url]: https://tracing-rs.netlify.com/tracing_serde ## Overview [`tracing`] is a framework for instrumenting Rust programs to collect scoped, structured, and async-aware diagnostics.`tracing-serde` enables serializing `tracing` types using [`serde`]. Traditional logging is based on human-readable text messages. `tracing` gives us machine-readable structured diagnostic information. This lets us interact with diagnostic data programmatically. With `tracing-serde`, you can implement a `Subscriber` to serialize your `tracing` types and make use of the existing ecosystem of `serde` serializers to talk with distributed tracing systems. Serializing diagnostic information allows us to do more with our logged values. For instance, when working with logging data in JSON gives us pretty-print when we're debugging in development and you can emit JSON and tracing data to monitor your services in production. The `tracing` crate provides the APIs necessary for instrumenting libraries and applications to emit trace data. *Compiler support: [requires `rustc` 1.63+][msrv]* [msrv]: #supported-rust-versions ## Usage First, add this to your `Cargo.toml`: ```toml [dependencies] tracing = "0.1" tracing-serde = "0.2" ``` Next, add this to your crate: ```rust use tracing_serde::AsSerde; ``` Please read the [`tracing` documentation](https://docs.rs/tracing/latest/tracing/index.html) for more information on how to create trace data. This crate provides the `as_serde` function, via the `AsSerde` trait, which enables serializing the `Attributes`, `Event`, `Id`, `Metadata`, and `Record` `tracing` values. For the full example, please see the [examples](../examples) folder. Implement a `Subscriber` to format the serialization of `tracing` types how you'd like. ```rust pub struct JsonSubscriber { next_id: AtomicUsize, // you need to assign span IDs, so you need a counter } impl Subscriber for JsonSubscriber { fn new_span(&self, attrs: &Attributes) -> Id { let id = self.next_id.fetch_add(1, Ordering::Relaxed); let id = Id::from_u64(id as u64); let json = json!({ "new_span": { "attributes": attrs.as_serde(), "id": id.as_serde(), }}); println!("{}", json); id } // ... } ``` After you implement your `Subscriber`, you can use your `tracing` subscriber (`JsonSubscriber` in the above example) to record serialized trace data. ## Supported Rust Versions Tracing is built against the latest stable release. The minimum supported version is 1.63. 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 1.69, the minimum supported version will not be increased past 1.66, 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](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. [`tracing`]: https://crates.io/crates/tracing [`serde`]: https://crates.io/crates/serde