10e722e808
It currently isn't possible to differentiate spans with the same name, target, and level when setting expectations on `enter`, `exit`, and `drop_span`. This is not an issue for `tracing-mock`'s original (and still primary) use case, which is to test `tracing` itself. However, when testing the tracing instrumentation in library or application code, this can be a limitation. For example, when testing the instrumentation in tokio (tokio-rs/tokio#6112), it isn't possible to set an expectation on which task span is entered first, because the name, target, and level of those spans are always identical - in fact, the spans have the same metadata and only the field values are different. To make differentiating different spans possible, `ExpectId` has been introduced. It is an opaque struct which represents a `span::Id` and can be used to match spans from a `new_span` expectation (where a `NewSpan` is accepted and all fields and values can be expected) through to subsequent `enter`, `exit`, and `drop_span` expectations. An `ExpectedId` is passed to an `ExpectedSpan` which then needs to be expected with `MockCollector::new_span`. A clone of the `ExpectedId` (or a clone of the `ExpectedSpan` with the `ExpectedId` already on it) will then match the ID assigned to the span to the other span lifecycle expectations. The `ExpectedId` uses an `Arc<AtomicU64>` which has the ID for the new span assigned to it, and then its clones will be matched against that same ID. In future changes it will also be possible to use this `ExpectedId` to match parent spans, currently a parent is only matched by name.
tracing-futures
Utilities for instrumenting futures-based code with tracing.
Overview
tracing is a framework for instrumenting Rust programs to collect
structured, event-based diagnostic information. This crate provides utilities
for using tracing to instrument asynchronous code written using futures and
async/await.
The crate provides the following traits:
-
Instrumentallows atracingspan to be attached to a future, sink, stream, or executor. -
WithSubscriberallows atracingSubscriberto be attached to a future, sink, stream, or executor.
Compiler support: requires rustc 1.63+
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.
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.