Struct Event 

pub struct Event {
    pub id: String,
    pub subject: String,
    pub category: String,
    pub event_type: String,
    pub version: u32,
    pub payload: Value,
    pub summary: String,
    pub source: String,
    pub timestamp: u64,
    pub metadata: HashMap<String, String>,
}

A single event in the system

Events are published to subjects following the dot-separated convention: events.<category>.<topic> (e.g., events.market.forex.usd_cny)

Fields

id: String

Unique event identifier (evt-)

subject: String

Subject this event was published to

category: String

Top-level category for grouping (e.g., “market”, “system”)

event_type: String

Event type identifier (e.g., “forex.rate_change”, “deploy.completed”)

Used by schema registry to look up validation rules. Defaults to empty string for untyped events.

version: u32

Schema version for this event type (e.g., 1, 2, 3)

Incremented when the payload schema changes. Defaults to 1 for new events.

payload: Value

Event payload — arbitrary JSON data

summary: String

Human-readable summary

source: String

Source system or service that produced this event

timestamp: u64

Unix timestamp in milliseconds

metadata: HashMap<String, String>

Optional key-value metadata

Implementations

impl Event

pub fn new( subject: impl Into<String>, category: impl Into<String>, summary: impl Into<String>, source: impl Into<String>, payload: Value, ) -> Self

Create a new event with auto-generated id and timestamp

pub fn typed( subject: impl Into<String>, category: impl Into<String>, event_type: impl Into<String>, version: u32, summary: impl Into<String>, source: impl Into<String>, payload: Value, ) -> Self

Create a typed event with explicit event_type and version

pub fn with_metadata( self, key: impl Into<String>, value: impl Into<String>, ) -> Self

Add a metadata entry

Trait Implementations

impl Clone for Event

fn clone(&self) -> Event

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Event

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Event

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<Event> for CloudEvent

Convert an A3S Event to a CloudEvent (lossless)

A3S-specific fields are stored as extension attributes:

• a3scategory — Event.category
• a3sversion — Event.version
• a3ssummary — Event.summary
• a3stimestamp — Event.timestamp (Unix ms)
• a3smeta_<key> — each metadata entry

fn from(event: Event) -> Self

Converts to this type from the input type.

impl Serialize for Event

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl TryFrom<CloudEvent> for Event

Convert a CloudEvent back to an A3S Event

Extracts A3S-specific fields from extension attributes. Fails if required A3S extensions are missing.

type Error = EventError

The type returned in the event of a conversion error.

fn try_from(ce: CloudEvent) -> Result<Self>

Performs the conversion.