#[span]Expand description
Wrap an operation in a span.
§Syntax
(control_param),* tpl, (property),*where
control_param: A Rust field-value with a pre-determined identifier (see below).tpl: A template string literal.property: A Rust field-value for a property to capture.
§Control parameters
This macro accepts the following optional control parameters:
| name | type | description |
|---|---|---|
rt | impl emit::runtime::Runtime | The runtime to emit the event through. |
mdl | impl Into<emit::Path> | The module the event belongs to. If unspecified the current module path is used. |
when | impl emit::Filter | A filter to use instead of the one configured on the runtime. |
guard | - | An identifier to bind an emit::Span to in the body of the span for manual completion. |
ok_lvl | str or emit::Level | Assume the instrumented block returns a Result. Assign the event the given level when the result is Ok. |
err_lvl | str or emit::Level | Assume the instrumented block returns a Result. Assign the event the given level when the result is Err and attach the error as the err property. |
panic_lvl | str or emit::Level | Detect whether the function panics and use the given level if it does. |
err | impl Fn(&E) -> T | Assume the instrumented block returns a Result. Map the Err variant into a new type U that is str, &(dyn Error + 'static), or impl Error + 'static |
setup | impl Fn() -> T | Invoke the expression before creating the span, binding the result to a value that’s dropped at the end of the annotated function. |
§Template
The template for the event. See the tpl macro for syntax.
§Properties
Properties that appear within the template or after it are added to the emitted event. The identifier of the property is its key. Property capturing can be adjusted through the as_* attribute macros.