Struct bevy::utils::tracing::event::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> ) -> Event<'a>

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> ) -> Event<'a>

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.

Examples found in repository

examples/app/log_layers_ecs.rs (line 59)

    fn on_event(
        &self,
        event: &tracing::Event<'_>,
        _ctx: tracing_subscriber::layer::Context<'_, S>,
    ) {
        // In order to obtain the log message, we have to create a struct that implements
        // Visit and holds a reference to our string. Then we use the `record` method and
        // the struct to modify the reference to hold the message string.
        let mut message = None;
        event.record(&mut CaptureLayerVisitor(&mut message));
        if let Some(message) = message {
            // You can obtain metadata like this, but we wont use it for this example.
            let _metadata = event.metadata();
            self.sender
                .send(LogEvent { message })
                .expect("LogEvents resource no longer exists!");
        }
    }

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.

Examples found in repository

examples/app/log_layers.rs (line 19)

    fn on_event(
        &self,
        event: &bevy::utils::tracing::Event<'_>,
        _ctx: bevy::log::tracing_subscriber::layer::Context<'_, S>,
    ) {
        println!("Got event!");
        println!("  level={:?}", event.metadata().level());
        println!("  target={:?}", event.metadata().target());
        println!("  name={:?}", event.metadata().name());
    }

examples/app/log_layers_ecs.rs (line 62)

    fn on_event(
        &self,
        event: &tracing::Event<'_>,
        _ctx: tracing_subscriber::layer::Context<'_, S>,
    ) {
        // In order to obtain the log message, we have to create a struct that implements
        // Visit and holds a reference to our string. Then we use the `record` method and
        // the struct to modify the reference to hold the message string.
        let mut message = None;
        event.record(&mut CaptureLayerVisitor(&mut message));
        if let Some(message) = message {
            // You can obtain metadata like this, but we wont use it for this example.
            let _metadata = event.metadata();
            self.sender
                .send(LogEvent { message })
                .expect("LogEvents resource no longer exists!");
        }
    }

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<(), Error>

Formats the value using the given formatter.

impl<'a> NormalizeEvent<'a> for Event<'a>

fn normalized_metadata(&'a self) -> Option<Metadata<'a>>

If this Event comes from a log, this method provides a new normalized Metadata which has all available attributes from the original log, including file, line, module_path and target. Returns None is the Event is not issued from a log.

fn is_log(&self) -> bool

Returns whether this Event represents a log (from the log crate)

impl<'a> RecordFields for Event<'a>

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

Record all the fields in self with the provided visitor.