| 1 | import * as AWS from "alchemy/AWS"; |
| 2 | import * as Context from "effect/Context"; |
| 3 | import * as Data from "effect/Data"; |
| 4 | import * as Effect from "effect/Effect"; |
| 5 | import * as Layer from "effect/Layer"; |
| 6 | import * as Stream from "effect/Stream"; |
| 7 | |
| 8 | import type { Job } from "./Job.ts"; |
| 9 | |
| 10 | export class NotifyJobError extends Data.TaggedError("NotifyJobError")<{ |
| 11 | readonly message: string; |
| 12 | readonly cause?: unknown; |
| 13 | }> {} |
| 14 | |
| 15 | type JobNotification = { |
| 16 | type: "job.created"; |
| 17 | job: Job; |
| 18 | }; |
| 19 | |
| 20 | export class JobNotifications extends Context.Service< |
| 21 | JobNotifications, |
| 22 | { |
| 23 | notifyJobCreated(job: Job): Effect.Effect<void, NotifyJobError>; |
| 24 | } |
| 25 | >()("JobNotifications") {} |
| 26 | |
| 27 | export const JobNotificationsSNS = Layer.provideMerge( |
| 28 | Layer.effect( |
| 29 | JobNotifications, |
| 30 | Effect.gen(function* () { |
| 31 | const topic = yield* AWS.SNS.Topic("JobNotificationsTopic", { |
| 32 | attributes: { |
| 33 | DisplayName: "job-notifications", |
| 34 | }, |
| 35 | }); |
| 36 | |
| 37 | const publish = yield* AWS.SNS.Publish(topic); |
| 38 | |
| 39 | yield* AWS.SNS.consumeTopicNotifications(topic, (stream) => |
| 40 | stream.pipe( |
| 41 | Stream.mapEffect((notification) => |
| 42 | Effect.try({ |
| 43 | try: () => JSON.parse(notification.Message) as JobNotification, |
| 44 | catch: (cause) => |
| 45 | new NotifyJobError({ |
| 46 | message: "Failed to parse SNS job notification", |
| 47 | cause, |
| 48 | }), |
| 49 | }).pipe( |
| 50 | Effect.flatMap((payload) => |
| 51 | Effect.logInfo( |
| 52 | `Job notification received: ${payload.type} (${payload.job.id})`, |
| 53 | ), |
| 54 | ), |
| 55 | // Keep the example resilient to malformed demo messages. |
| 56 | Effect.catchTag("NotifyJobError", (error) => |
| 57 | Effect.logWarning(error.message), |
| 58 | ), |
| 59 | ), |
| 60 | ), |
| 61 | Stream.runDrain, |
| 62 | ), |
| 63 | ); |
| 64 | |
| 65 | const notifyJobCreated = (job: Job) => |
| 66 | publish({ |
| 67 | Subject: "JobCreated", |
| 68 | Message: JSON.stringify({ |
| 69 | type: "job.created", |
| 70 | job, |
| 71 | } satisfies JobNotification), |
| 72 | }).pipe( |
| 73 | Effect.asVoid, |
| 74 | Effect.mapError( |
| 75 | (cause) => |
| 76 | new NotifyJobError({ |
| 77 | message: `Failed to publish job notification for "${job.id}"`, |
| 78 | cause, |
| 79 | }), |
| 80 | ), |
| 81 | ); |
| 82 | |
| 83 | return JobNotifications.of({ |
| 84 | notifyJobCreated, |
| 85 | }); |
| 86 | }), |
| 87 | ), |
| 88 | Layer.mergeAll(AWS.Lambda.TopicEventSource, AWS.SNS.PublishHttp), |
| 89 | ); |