| 1 | import type * as Effect from "effect/Effect"; |
| 2 | import type * as Stream from "effect/Stream"; |
| 3 | import { |
| 4 | consumeBusEvents, |
| 5 | type EventRecord, |
| 6 | type EventRouteProps, |
| 7 | } from "../EventBridge/EventSource.ts"; |
| 8 | |
| 9 | /** |
| 10 | * The `detail` payload Amazon Fraud Detector delivers to EventBridge when |
| 11 | * event orchestration is enabled on an event type and a prediction is |
| 12 | * generated. The payload mirrors the `GetEventPrediction` inputs and results; |
| 13 | * fields are optional because the schema grows over time. |
| 14 | */ |
| 15 | export interface PredictionEventDetail { |
| 16 | /** Id of the evaluated event. */ |
| 17 | eventId?: string; |
| 18 | /** Name of the event type the event belongs to. */ |
| 19 | eventTypeName?: string; |
| 20 | /** Id of the detector that produced the prediction. */ |
| 21 | detectorId?: string; |
| 22 | /** Version of the detector that produced the prediction. */ |
| 23 | detectorVersionId?: string; |
| 24 | /** ISO-8601 timestamp of the evaluated event. */ |
| 25 | eventTimestamp?: string; |
| 26 | /** Entities the event was recorded against. */ |
| 27 | entities?: ReadonlyArray<Record<string, unknown>>; |
| 28 | /** Variable values the prediction was computed from. */ |
| 29 | eventVariables?: Record<string, unknown>; |
| 30 | /** Matched-rule results, including the returned outcomes. */ |
| 31 | ruleResults?: ReadonlyArray<Record<string, unknown>>; |
| 32 | /** Model scores, when the detector uses models. */ |
| 33 | modelScores?: ReadonlyArray<Record<string, unknown>>; |
| 34 | /** Additional event fields (the schema grows over time). */ |
| 35 | [key: string]: unknown; |
| 36 | } |
| 37 | |
| 38 | /** A Fraud Detector prediction EventBridge event delivered to the handler. */ |
| 39 | export type PredictionEvent = EventRecord<PredictionEventDetail>; |
| 40 | |
| 41 | export interface PredictionEventSourceProps extends EventRouteProps { |
| 42 | /** |
| 43 | * Logical id for the backing EventBridge rule. |
| 44 | * @default "FraudDetectorPredictions" |
| 45 | */ |
| 46 | id?: string; |
| 47 | /** |
| 48 | * Restrict to predictions for specific event types (matched against the |
| 49 | * event's `eventTypeName`). |
| 50 | */ |
| 51 | eventTypeNames?: readonly string[]; |
| 52 | /** |
| 53 | * Restrict to predictions produced by specific detectors (matched against |
| 54 | * the event's `detectorId`). |
| 55 | */ |
| 56 | detectorIds?: readonly string[]; |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * Event source connecting Amazon Fraud Detector prediction results to the |
| 61 | * hosting compute. When event orchestration is enabled on an event type |
| 62 | * (`EventType` with `eventBridgeEnabled: true`), every `GetEventPrediction` |
| 63 | * result is published to the account's default EventBridge bus (source |
| 64 | * `aws.frauddetector`, detail-type `Event Prediction Result Returned`); this |
| 65 | * subscribes the host Function to those events so it can trigger downstream |
| 66 | * workflows — queue a manual review, block an account, notify the customer. |
| 67 | * |
| 68 | * Fraud Detector publishes to EventBridge automatically — no additional |
| 69 | * resource is created besides the EventBridge rule targeting the host. |
| 70 | * Provide the host-specific implementation layer (e.g. |
| 71 | * `AWS.Lambda.EventSource`) on the Function effect. |
| 72 | * |
| 73 | * ### Consuming Prediction Results |
| 74 | * **Example:** React To High-Risk Predictions |
| 75 | * ```typescript |
| 76 | * import * as AWS from "alchemy/AWS"; |
| 77 | * |
| 78 | * export default ReviewFunction.make( |
| 79 | * { main: import.meta.url }, |
| 80 | * Effect.gen(function* () { |
| 81 | * yield* AWS.FraudDetector.consumePredictionEvents( |
| 82 | * { eventTypeNames: ["purchase"] }, |
| 83 | * (events) => |
| 84 | * Stream.runForEach(events, (event) => |
| 85 | * Effect.log( |
| 86 | * `prediction for ${event.detail.eventId}: ` + |
| 87 | * JSON.stringify(event.detail.ruleResults), |
| 88 | * ), |
| 89 | * ), |
| 90 | * ); |
| 91 | * return {}; |
| 92 | * }).pipe(Effect.provide(AWS.Lambda.EventSource)), |
| 93 | * ); |
| 94 | * ``` |
| 95 | */ |
| 96 | export const consumePredictionEvents = <StreamReq = never, Req = never>( |
| 97 | props: PredictionEventSourceProps, |
| 98 | process: ( |
| 99 | events: Stream.Stream<PredictionEvent, never, StreamReq>, |
| 100 | ) => Effect.Effect<void, never, Req>, |
| 101 | ) => |
| 102 | consumeBusEvents( |
| 103 | props.id ?? "FraudDetectorPredictions", |
| 104 | { |
| 105 | source: ["aws.frauddetector"], |
| 106 | "detail-type": ["Event Prediction Result Returned"], |
| 107 | ...(props.eventTypeNames !== undefined || props.detectorIds !== undefined |
| 108 | ? { |
| 109 | detail: { |
| 110 | ...(props.eventTypeNames !== undefined |
| 111 | ? { eventTypeName: [...props.eventTypeNames] } |
| 112 | : {}), |
| 113 | ...(props.detectorIds !== undefined |
| 114 | ? { detectorId: [...props.detectorIds] } |
| 115 | : {}), |
| 116 | }, |
| 117 | } |
| 118 | : {}), |
| 119 | }, |
| 120 | { description: props.description, state: props.state }, |
| 121 | process, |
| 122 | ); |