EngineMessage¶

Purpose¶

A message sent to a pub/sub topic by an engine.

Type¶

Reception:

EngineMessageV1

Record with fields:

src: EngineIdentity

Source engine identity

dst: DestinationIdentity

Destination identity

id: u64

Message ID: unique per src-dst pairs

reply_to: Option

id of a previous message this message is in reply to

expiry Option

Expiry time for outgoing messages. See P2PMessage & TransportMessage.

rprefs: Option<RoutingPrefs>

Routing preferences

tprefs: Option<TransportPrefs>

Transport preferences

protocol: Protocol

Protocol & version used in body

body: Vec

Serialized message body

sig: Option

Signature over the above fields by src

Triggers:

Event

Behaviour¶

When a local engine sends an EngineMessage destined to a pub/sub topic, the Router forwards it to all local engines subscribed to the message, including PubSub.

PubSub then encapsulates the message in an Event, and forwards it to its neighbors along the event dissemination path.

Message flow¶

sequenceDiagram

%% --8<-- [start:sequence]
Any Local Engine -) Router: EngineMessage
Router -) PubSub: EngineMessage
PubSub -) PubSub: Event
%% --8<-- [end:sequence]