# tokio-rs/tracing

Application level tracing for Rust.

Repository: https://github.com/tokio-rs/tracing
Canonical: https://ross.abutalabs.com/products/tracing
Homepage: https://tracing.rs
Language: Rust
License: MIT
License Family: permissive
Topics: rust, rust-lang, tracing, logging, logging-library, logging-facade, logging-and-metrics, diagnostics
Last push: 2026-05-30T06:42:00+00:00

## Health v2 (maintenance only)
Score: 86/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 85, release rhythm 80, longevity 100
- inputs: {"age_days": 2791, "days_push": 95, "days_rel": 138, "gap_med": 0.0, "n_releases_24m": 23}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6856, forks 925 (observed 2026-08-28T04:09:50.926452+00:00)

## What it is
tracing is a Rust framework for instrumenting applications to emit structured, event-based diagnostic data, built around spans with duration and causality rather than single log lines. It is maintained by the Tokio project but works without the Tokio runtime, and integrates with the log ecosystem via tracing-subscriber.

## Use cases
- add structured logging to a Rust application
- trace async task execution across interleaved futures
- instrument library code with spans and events
- collect distributed tracing data from Rust services
- replace println debugging with proper diagnostics
- bridge log-crate output into a structured tracing subscriber

## When to choose
- you need structured, contextual diagnostics in Rust, especially for async/concurrent code
- you want spans with timing and causality rather than flat log lines
- you need a widely adopted, production-proven logging facade with subscriber ecosystem

## When to avoid
- you only need simple println-style logging in a small script
- your project is not written in Rust
- you need a full metrics or APM solution rather than trace instrumentation

## Facets
- artifact type: library
- maturity: stable
- function: logging, tracing, monitoring
- domain: developer-tools, backend, performance
- platform: rust, cross-platform
- tags: structured-logging, diagnostics, async, spans, observability, tokio

## Member repositories
- tokio-rs/tracing (main) score 86

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:50.926452+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:41:44.429970+00:00, confidence not recorded.
  - readme: https://github.com/tokio-rs/tracing (fetched 2026-08-28T04:09:50.926452+00:00, sha 1d82b7387eaf)
  - homepage: https://tracing.rs (fetched 2026-08-29T08:37:43.567956+00:00, sha 9e77ce46cbe9)
  - registry_crates: https://crates.io/api/v1/crates/tracing (fetched 2026-08-29T08:37:43.583182+00:00, sha a89f7f028614)
  - site_page: https://tracing.rs/tracing/struct.span (fetched 2026-08-29T08:37:43.577960+00:00, sha 6cbd70ff5de9)
- Data as of 2026-08-30T08:39:29.467469+00:00.