SNS

Overview

CloudMock emulates Amazon SNS, a pub/sub messaging service, supporting topic management, subscriptions, message publishing with fan-out to SQS subscribers, and tagging.

Supported Operations

Operation	Status	Notes
CreateTopic	Supported	Creates a topic and returns its ARN
DeleteTopic	Supported	Deletes a topic and all its subscriptions
ListTopics	Supported	Returns all topic ARNs
GetTopicAttributes	Supported	Returns topic attributes
SetTopicAttributes	Supported	Sets topic attributes
Subscribe	Supported	Creates a subscription (SQS, HTTP, email, Lambda)
Unsubscribe	Supported	Removes a subscription
ListSubscriptions	Supported	Returns all subscriptions
ListSubscriptionsByTopic	Supported	Returns subscriptions for a specific topic
Publish	Supported	Publishes a message; fans out to SQS subscribers
TagResource	Supported	Adds tags to a topic
UntagResource	Supported	Removes tags from a topic

Quick Start

curl

# Create a topic
curl -X POST "http://localhost:4566/?Action=CreateTopic&Name=notifications"

# Subscribe an SQS queue
curl -X POST "http://localhost:4566/?Action=Subscribe&TopicArn=arn:aws:sns:us-east-1:000000000000:notifications&Protocol=sqs&Endpoint=arn:aws:sqs:us-east-1:000000000000:my-queue"

# Publish a message
curl -X POST "http://localhost:4566/?Action=Publish&TopicArn=arn:aws:sns:us-east-1:000000000000:notifications&Message=Hello"

Node.js

import { SNSClient, CreateTopicCommand, PublishCommand, SubscribeCommand } from '@aws-sdk/client-sns';

const sns = new SNSClient({
  endpoint: 'http://localhost:4566',
  region: 'us-east-1',
  credentials: { accessKeyId: 'test', secretAccessKey: 'test' },
});

const { TopicArn } = await sns.send(new CreateTopicCommand({ Name: 'alerts' }));
await sns.send(new SubscribeCommand({
  TopicArn, Protocol: 'sqs',
  Endpoint: 'arn:aws:sqs:us-east-1:000000000000:my-queue',
}));
await sns.send(new PublishCommand({ TopicArn, Message: 'Something happened' }));

Python

import boto3

sns = boto3.client('sns', endpoint_url='http://localhost:4566',
                   aws_access_key_id='test', aws_secret_access_key='test',
                   region_name='us-east-1')

topic = sns.create_topic(Name='alerts')
topic_arn = topic['TopicArn']

sns.subscribe(TopicArn=topic_arn, Protocol='sqs',
              Endpoint='arn:aws:sqs:us-east-1:000000000000:my-queue')
sns.publish(TopicArn=topic_arn, Message='Something happened', Subject='Alert')

Configuration

cloudmock.yml

services:
  sns:
    enabled: true

No additional service-specific configuration is required.

Known Differences from AWS

• Fan-out to SQS is implemented: publishing to a topic delivers the message to all subscribed SQS queues within CloudMock.
• HTTP/HTTPS and email protocol subscriptions are stored but delivery is not attempted.
• Lambda subscriptions record the ARN but do not invoke the function.
• Message filtering by subscription filter policies is not implemented.
• FIFO topics are not implemented.
• Platform applications (mobile push) are not implemented.

Error Codes

Code	HTTP Status	Description
NotFound	404	The specified topic does not exist
InvalidParameter	400	An input parameter is invalid
SubscriptionLimitExceeded	400	Too many subscriptions on this topic
AuthorizationError	403	Not authorized to perform this action