RabbitMQ Dead Letter Queue

RabbitMQ Dead Letter Queue

Introduction

To prevent data loss of RabbitMQ queue, Insights product will handle this with help of RabbitMQ dead letter queue.

Pre-Requisite:

• Dead letter exchanges (DLXs) are normal exchanges, Insights planning maintain one queue for whole application.
• DLX attached to normal queue (Health and Data) at the time declaration of queue, this means that user has to delete all their queue before activating DLX in their environment.
• Insights Version 8.1+ support this functionality
• If you already have agent registered, do the following steps in sequence
  • Stop All Agent
  • Consume all data from queue
  • Stop Engine, Daemon Agent and platform service
  • Delete all existing queue
  • Activate DLX mention in below section and start all services

Activation:

1. Activate it in all configuration files mentioned below

In server-config for PaltformService and PlatfromEngine

• Enable enableDeadLetterExchange in messageQueue section of server-config.json

"messageQueue": {
"host": "localhost",
"port": 5672,
"user": "",
"password": "",
"prefetchCount": 5,
"enableDeadLetterExchange":false
},
In Deamon Agent and In Agent

• Enable enableDeadLetterExchange in mqConfig section of Config.json

In PlatformInsightsWebHook

• Enable app.enableDeadLetterExchange in webhook_subscriber.properties

1. Restart all services after property changes

How to use it

• One user activates DLX, application will create "iRecover" Exchange name with type "fanout" in RabbitMq
• INSIGHTS_RECOVER_QUEUE will be created.
• Declaration of DLX in RabbitMQ

Queue

Exchange

Agent/Webhook Queue

• When any exception occurs during processing of messages then Insights application Reject that message and it will send to DLX Queue
• Message in INSIGHTS_RECOVER_QUEUE of DLX contain in following format

Upgrading from older version of Insights

• • Stop All Agent
  • Consume all data from queue
  • Stop Engine, Daemon Agent and platform service
  • Delete all existing queue
  • Activate DLX mention in above section
  • start all services

Deactivating DLX

• • Stop All Agent
  • Consume all data from queue
  • Stop Engine, Daemon Agent and platform service
  • Delete all existing queue
  • Deactivate DLX by disabling enableDeadLetterExchange to false in server-config.json, Agnets config.json and daemon agent config.json
  • Start all services