iii-trigger-conditions

name	iii-trigger-conditions
description	Registers a boolean condition function and attaches it to triggers via condition_function_id so handlers only fire when the condition passes. Use when gating triggers on business rules, checking user permissions, validating data before processing, filtering high-value orders, rate-limiting events, or conditionally skipping handlers based on payload content.

Trigger Conditions

Comparable to: Middleware guards, event filters

Key Concepts

Use the concepts below when they fit the task. Not every trigger needs a condition.

• A Condition Function is a registered function that returns a boolean (true or false)
• The engine calls the condition function before the handler; the handler runs only if true
• Attach a condition to any trigger type via condition_function_id in the trigger config
• The condition function receives the same event data as the handler would
• Works with all trigger types: http, durable:subscriber, cron, state, stream, subscribe

Architecture

When a trigger fires, the engine first invokes the condition function with the event data. If the condition returns true, the handler executes normally. If false, the handler is skipped silently with no error or retry.

iii Primitives Used

Primitive	Purpose
registerFunction(id, handler) (condition)	Register the condition function (returns boolean)
registerFunction(id, handler) (handler)	Register the handler function
registerTrigger({ type, function_id, config: { condition_function_id } })	Bind trigger with condition gate