Event-Driven Architecture - Proof of Concept

Start Development Environment

Requirements:

• NodeJS > v18
• NVM
• Golang > 1.20
• Docker
• MQTT-Explorer [useful but not mandatory]
• Terraform
• AWS CLI

nvm use 18.12.1
cd starter && ./start.sh

# Open Browser
open http://localhost:8030

# Start the mock device
cd mock-device && npm run dev

Frontend

This service is the frontend application that will connect to the backend application (http and websockets), display device information and send remote actions to the device.

Backend

This service is the backend application that will receive the messages from the message processor through SQS queue, and send remote actions to the SNS topic.

Gateway Websockets

This service is responsible for handling the websocket connections (frontend application) and forward the messages to the backend service.

Independent Usage

Connect to the websocket endpoint using Websocket King client

ws://localhost:9001/ws?deviceId=myDevice1234

Send a message to the websocket endpoint

POST http://localhost:9001/send
{
    "connectionId": "9215e3e1-fbb0-46f9-8a21-071fee6188c2",
    "payload": "{\"foo\":\"bar\"}"
}

Message Processor

This service is a message processor that:

• Receive the messages from the IoT devices (MQTT) and send them to the SNS topic.
• Receive commands from the SQS queue and send them to the IoT device.
• Manage the connectivity status of the IoT devices (using the Last Will Testament funcionality of MQTT).

MQTT Broker

The MQTT broker will be available on localhost:1883

Mock Device

This service is a mock device that will connect to the MQTT broke, send events and receive commands from the MQTT broker.

Configuration

The config file is in the file mosquito.conf

By default we activated the log and data persistance (logs are in the starter/volumes/mqtt/log folder, and data are stored in starter/volumes/mqtt/data folder).

Authentication

The default user is admin/password.

You always have to restart if you want the modification to be taken in account:

docker compose restart

Change user password / create a new user

docker compose exec mqtt-broker mosquitto_passwd -b /mosquitto/config/password.txt user password

Delete user

docker compose exec mqtt-broker mosquitto_passwd -D /mosquitto/config/password.txt user

Notes

• SQS Admin UI for managing SQS-Queues for local development

• React app created with Vite

npm create vite@latest

• List SNS topics

aws --endpoint-url=http://localhost:4566 sns list-topics | cat

• List SQS queues

aws --endpoint-url=http://localhost:4566 sqs list-queues | cat

• List SNS subscriptions

aws --endpoint-url=http://localhost:4566 sns list-subscriptions | cat

• Websockets Endpoint

ws://localhost:9001/ws?deviceId=myDevice1234 (from host)
ws://gateway-ws:9001/ws?deviceId=myDevice1234 (from container)

• Localstack health endpoint

http://localhost:4566/\_localstack/health

• Send command message to SQS queue:

aws --endpoint-url=http://localhost:4566 sqs send-message --queue-url http://localstack:4566/000000000000/to-device-sqs-queue --message-body '{"Type": "Notification", "MessageId": "08efc4d6-8254-4404-9c24-b5b516ab5146", "TopicArn": "arn:aws:sns:eu-central-1:000000000000:to-device-sns-topic", "Message": "{\"command\":\"DISABLE_TELEMETRY\",\"command_version\":\"1.0\",\"json_command_rfc\":\"1.0\",\"command_id\":\"01H3FTJGBEVJYM23491RBJ6ADX\",\"producer\":\"backend\",\"sent_on\":1687379591534,\"parameters\":{\"id\":\"ANTONIOMARTINEZCUSTOMULID1\",\"payload\":{}},\"meta\":{\"service\":\"backend\",\"version\":\"1.0\",\"created_at\":1687379591534}}", "Timestamp": "2023-06-21T20:33:11.542Z", "SignatureVersion": "1", "Signature": "EXAMPLEpH+..", "SigningCertURL": "https://sns.us-east-1.amazonaws.com/SimpleNotificationService-0000000000000000000000.pem", "UnsubscribeURL": "http://localhost:4566/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:eu-central-1:000000000000:to-device-sns-topic:65825848-8292-4623-b416-307c62bbba48"}' | cat