# pkg/eventbus Package handles event dispatching and trigger registration ## Event Event (in context of eventbus package) contains of resource type, event type and a matcher. ### Resource type Resource types are identifiers of internal resources, like user, role, request, ... ### Event type Type describes direct or indirect user action or some other event in the system. ### Event matcher Matcher is a function on event that helps filtering fired events. It decides (returns true or false) if fired event is a match for any of a registered triggers Bus has basic internal filtering for resource & event type. Other constraints are passed to event's matcher function. .Matcher will receive 2+ string parameters: - name - operator - zero or more values It's matcher responsibility to handle contents of name, operator and values parameters. Constraint checker procedure will call matcher for each constraint. All constraints must match. First non-match will break constraint checking procedure. ## Triggers Trigger is combination of (event matching) rules/constraints and event handler. Handler is a callback function called when a compatible event is fired. Trigger can respond to multiple resource/event combinations. ### Constraints Matcher function is called multiple times, once per each trigger constraint. If any of the calls result in a non-match, check Trigger without constraint is considered a match. ### Weight Weight controls order of trigger execution.