Fjall Docs — Deploy Production-Ready AWS Infrastructure in Minutes

Overview

The SNSTopic construct creates an Amazon SNS topic for pub/sub messaging. Use it to fan out events to multiple subscribers (Lambda, SQS, HTTP endpoints) from a single publish call.

Import

import { SNSTopic } from "@fjall/components-infrastructure/lib/resources/aws/messaging/sns";

Basic Usage

const topic = new SNSTopic(scope, "Alerts", {});

Using the Messaging Factory

The recommended way to add SNS to a Fjall application is through the MessagingFactory:

import { MessagingFactory } from "@fjall/components-infrastructure/lib/patterns/aws/messaging";

const alerts = app.addMessaging(
  MessagingFactory.build("Alerts", {
    type: "topic",
  }),
);

Properties

Property	Type	Default	Description
`topicName`	`string`	Auto-generated	Topic name
`displayName`	`string`	None	Human-readable name for SMS subscriptions
`fifo`	`boolean`	`false`	Create a FIFO topic (strict ordering)
`contentBasedDeduplication`	`boolean`	`true` (FIFO)	Content-based deduplication. Defaults to `true` on FIFO topics, ignored on standard topics
`removalPolicy`	`"DESTROY" \| "RETAIN"`	`"RETAIN"`	What happens on stack deletion

Methods

Method	Returns	Description
`getTopicArn()`	`string`	Topic ARN
`getTopicName()`	`string`	Topic name
`getTopic()`	`ITopic`	CDK Topic construct
`grantPublish(grantee)`	`Grant`	Grant permission to publish messages
`grantSubscribe(grantee)`	`Grant`	Grant permission to subscribe to the topic

Examples

Standard Topic

const notifications = app.addMessaging(
  MessagingFactory.build("Notifications", {
    type: "topic",
    displayName: "Order Notifications",
  }),
);

notifications.grantPublish(apiService);

FIFO Topic

FIFO topics deliver messages in order and support deduplication:

const events = app.addMessaging(
  MessagingFactory.build("Events", {
    type: "topic",
    fifo: true,
    contentBasedDeduplication: true,
  }),
);

Fan-Out to Multiple Queues

Combine SNS with SQS for fan-out patterns:

import { SqsSubscription } from "aws-cdk-lib/aws-sns-subscriptions";

const orderTopic = app.addMessaging(
  MessagingFactory.build("OrderEvents", {
    type: "topic",
  }),
);

const billingQueue = app.addMessaging(
  MessagingFactory.build("Billing", {
    type: "queue",
  }),
);

const shippingQueue = app.addMessaging(
  MessagingFactory.build("Shipping", {
    type: "queue",
  }),
);

// Subscribe queues to the topic
orderTopic
  .getTopic()
  .addSubscription(new SqsSubscription(billingQueue.getQueue()));
orderTopic
  .getTopic()
  .addSubscription(new SqsSubscription(shippingQueue.getQueue()));

CloudFormation Outputs

Output	Description
`{id}TopicArn`	Topic ARN
`{id}TopicName`	Topic name

Compute Resources

Database Resources

Storage Resources

Networking Resources

Messaging Resources

Security Resources

SNS Topic

Overview

Import

Basic Usage

Using the Messaging Factory

Properties

Methods

Examples

Standard Topic

FIFO Topic

Fan-Out to Multiple Queues

CloudFormation Outputs

Next Steps

Messaging Factory

SQS Queue

​Overview

​Import

​Basic Usage

​Using the Messaging Factory

​Properties

​Methods

​Examples

​Standard Topic

​FIFO Topic

​Fan-Out to Multiple Queues

​CloudFormation Outputs

​Next Steps

Messaging Factory

SQS Queue

Overview

Import

Basic Usage

Using the Messaging Factory

Properties

Methods

Examples

Standard Topic

FIFO Topic

Fan-Out to Multiple Queues

CloudFormation Outputs

Next Steps