Topic

Source: src/AWS/SNS/Topic.ts

An Amazon SNS topic for fan-out messaging and notifications.

Topic owns the SNS topic lifecycle while raw AWS topic attributes remain available through the attributes prop so the full core pub/sub surface can be configured without waiting on additional typed wrappers. A topic name is auto-generated unless you provide one explicitly.

Creating Topics

Standard Topic

import * as SNS from "alchemy/AWS/SNS";

const topic = yield* SNS.Topic("OrdersTopic");

Topic with Display Name

const topic = yield* SNS.Topic("NotificationsTopic", {
  attributes: {
    DisplayName: "App Notifications",
  },
});

FIFO Topic

const topic = yield* SNS.Topic("OrdersFifoTopic", {
  fifo: true,
  attributes: {
    ContentBasedDeduplication: "true",
  },
});

Runtime Publishing

Bind publish operations in the init phase and use them in runtime handlers.

// init
const publish = yield* SNS.Publish.bind(topic);

return {
  fetch: Effect.gen(function* () {
    // runtime
    yield* publish({
      Message: JSON.stringify({ orderId: "123" }),
      Subject: "OrderCreated",
    });
    return HttpServerResponse.text("Published");
  }),
};

Subscriptions

Subscribe a Lambda function to process messages published to the topic. The subscription and invoke permissions are created automatically.

// init
yield* SNS.notifications(topic).subscribe((stream) =>
  stream.pipe(
    Stream.runForEach((message) =>
      Effect.log(`Received: ${message.Message}`),
    ),
  ),
);