Struct tracing_core::Event

pub struct Event<'a> { /* private fields */ }

Events represent single points in time where something occurred during the execution of a program.

An Event can be compared to a log record in unstructured logging, but with two key differences:

• Events exist within the context of a span. Unlike log lines, they may be located within the trace tree, allowing visibility into the temporal context in which the event occurred, as well as the source code location.
• Like spans, Events have structured key-value data known as fields, which may include textual message. In general, a majority of the data associated with an event should be in the event’s fields rather than in the textual message, as the fields are more structured.

Implementations

impl<'a> Event<'a>

pub fn dispatch(metadata: &'static Metadata<'static>, fields: &'a ValueSet<'_>)

Constructs a new Event with the specified metadata and set of values, and observes it with the current subscriber.

pub fn new( metadata: &'static Metadata<'static>, fields: &'a ValueSet<'a>, ) -> Self

Returns a new Event in the current span, with the specified metadata and set of values.

pub fn new_child_of( parent: impl Into<Option<Id>>, metadata: &'static Metadata<'static>, fields: &'a ValueSet<'a>, ) -> Self

Returns a new Event as a child of the specified span, with the provided metadata and set of values.

pub fn child_of( parent: impl Into<Option<Id>>, metadata: &'static Metadata<'static>, fields: &'a ValueSet<'_>, )

Constructs a new Event with the specified metadata and set of values, and observes it with the current subscriber and an explicit parent.

pub fn record(&self, visitor: &mut dyn Visit)

Visits all the fields on this Event with the specified visitor.

pub fn fields(&self) -> Iter

Returns an iterator over the set of values on this Event.

pub fn metadata(&self) -> &'static Metadata<'static>

Returns metadata describing this Event.

pub fn is_root(&self) -> bool

Returns true if the new event should be a root.

pub fn is_contextual(&self) -> bool

Returns true if the new event’s parent should be determined based on the current context.

If this is true and the current thread is currently inside a span, then that span should be the new event’s parent. Otherwise, if the current thread is not inside a span, then the new event will be the root of its own trace tree.

pub fn parent(&self) -> Option<&Id>

Returns the new event’s explicitly-specified parent, if there is one.

Otherwise (if the new event is a root or is a child of the current span), returns None.

Trait Implementations

impl<'a> Debug for Event<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes