Events

Argos Mesh uses an event-driven architecture with RabbitMQ for asynchronous communication between microservices. This page documents the internal events used across the system.

Event Overview

The system publishes three main types of internal events:

ProductSoldInternalEvent - Published when a product is sold
ProductCreatedInternalEvent - Published when a new product is created
AlertInternalEvent - Published when suspicious activity is detected

ProductSoldInternalEvent

Published by the Orders service when a product sale transaction is completed. This event is consumed by the Sentinel service for fraud detection and monitoring.

Event Schema

package com.argos.orders.dto.event;

import java.time.LocalDateTime;

public record ProductSoldInternalEvent(
    Long productID,
    Integer quantity,
    String ipAddress,
    LocalDateTime timeStamp
)

Fields

productID

Long

required

The unique identifier of the product that was sold

quantity

Integer

required

The number of units sold in the transaction

ipAddress

String

required

The client IP address from which the purchase was made. Used for fraud detection and geographic analysis.

timeStamp

LocalDateTime

required

The exact date and time when the sale occurred in ISO-8601 format

Message Configuration

Queue

String

argos.sales.queue

Exchange

String

shop.exchange (Topic Exchange)

Routing Key

String

shop.event.sold

Event Example

{
  "productID": 1,
  "quantity": 5,
  "ipAddress": "192.168.1.100",
  "timeStamp": "2026-03-05T14:30:45.123"
}

Event Flow

The Orders service uses the shop.exchange Topic Exchange to allow multiple consumers to process sale events independently.

ProductCreatedInternalEvent

Published by the Orders service when a new product is successfully created in the system.

Event Schema

package com.argos.orders.dto.event;

import com.argos.orders.dto.ProductResponse;

public record ProductCreatedInternalEvent(ProductResponse response)

Fields

response

ProductResponse

required

The complete product information including the newly generated ID

Show ProductResponse Schema

public record ProductResponse(
    Long productID,
    String productName,
    BigDecimal productPrice,
    Integer productStock
)

Message Configuration

Queue

String

argos.products.mgmt.queue

Exchange

String

shop.exchange (Topic Exchange)

Routing Key

String

shop.event.product.# (wildcard pattern)

Event Example

{
  "response": {
    "productID": 42,
    "productName": "Laptop",
    "productPrice": 999.99,
    "productStock": 50
  }
}

The routing key uses a wildcard pattern (shop.event.product.#) to allow for future product-related events such as shop.event.product.updated or shop.event.product.deleted.

AlertInternalEvent

Published by the Sentinel service when suspicious activity or security threats are detected, such as DDoS attacks or unusual purchasing patterns.

Event Schema

package com.argos.notify.dto;

import java.time.LocalDateTime;

public record AlertInternalEvent(
    String type,
    String sourceIp,
    String severity,
    LocalDateTime timeStamp
)

Fields

type

String

required

The type of alert detected. Common values:

DDoS Attack
Suspicious Purchase Pattern
Rate Limit Exceeded
Inventory Manipulation

sourceIp

String

required

The IP address associated with the suspicious activity (e.g., 127.0.0.1, 192.168.1.100)

severity

String

required

The severity level of the alert:

CRITICAL - Immediate action required
HIGH - Requires urgent attention
MEDIUM - Should be investigated
LOW - Informational

timeStamp

LocalDateTime

required

When the alert was generated in ISO-8601 format

Message Configuration

Queue

String

argos.alert.queue

Exchange

String

alert.exchange (Topic Exchange)

Routing Key

String

argos.alert.# (wildcard pattern)

Event Example

{
  "type": "DDoS Attack",
  "sourceIp": "203.0.113.42",
  "severity": "CRITICAL",
  "timeStamp": "2026-03-05T14:35:22.789"
}

Consumers

The AlertInternalEvent is consumed by:

Notify Service - Sends notifications to administrators via email, SMS, or other channels
Security Dashboard - Updates real-time monitoring displays
Logging System - Archives alerts for compliance and audit purposes

CRITICAL severity alerts trigger immediate notifications and may automatically block the source IP address depending on system configuration.

RabbitMQ Configuration

Exchanges

The system uses two main Topic Exchanges:

Exchange Name	Purpose
`shop.exchange`	Product and sales events
`alert.exchange`	Security and monitoring alerts

Queues

Queue Name	Bound To	Routing Key	Consumer
`argos.sales.queue`	`shop.exchange`	`shop.event.sold`	Sentinel Service
`argos.products.mgmt.queue`	`shop.exchange`	`shop.event.product.#`	Product Management
`argos.alert.queue`	`alert.exchange`	`argos.alert.#`	Notify Service

Message Serialization

All events are serialized as JSON using Jackson with the following configuration:

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());
mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

The JavaTimeModule ensures that LocalDateTime fields are serialized as ISO-8601 strings rather than timestamps.

Event Publishing

From Orders Service

The Orders service publishes events using Spring AMQP:

// Publishing a ProductSoldInternalEvent
ProductSoldInternalEvent event = new ProductSoldInternalEvent(
    productId,
    quantity,
    clientIp,
    LocalDateTime.now()
);

rabbitTemplate.convertAndSend(
    "shop.exchange",
    "shop.event.sold",
    event
);

From Sentinel Service

The Sentinel service publishes alerts:

// Publishing an AlertInternalEvent
AlertInternalEvent alert = new AlertInternalEvent(
    "DDoS Attack",
    sourceIp,
    "CRITICAL",
    LocalDateTime.now()
);

rabbitTemplate.convertAndSend(
    "alert.exchange",
    "argos.alert.critical",
    alert
);

Event Consumption

Listening to Sales Events

@RabbitListener(queues = "argos.sales.queue")
public void handleProductSold(ProductSoldInternalEvent event) {
    // Process the sale event
    log.info("Product {} sold: {} units from IP {}",
        event.productID(),
        event.quantity(),
        event.ipAddress());
    
    // Perform fraud analysis
    fraudDetectionService.analyze(event);
}

Listening to Alert Events

@RabbitListener(queues = "argos.alert.queue")
public void handleAlert(AlertInternalEvent alert) {
    // Send notification based on severity
    if ("CRITICAL".equals(alert.severity())) {
        notificationService.sendUrgentAlert(alert);
    } else {
        notificationService.logAlert(alert);
    }
}

Best Practices

Event Idempotency

Consumers should be designed to handle duplicate events gracefully. Use unique transaction IDs or timestamps to detect and skip duplicate processing.

Error Handling

Implement dead letter queues (DLQs) for messages that fail processing. Configure retry policies with exponential backoff.

Monitoring

Monitor queue depths, message rates, and consumer lag to ensure healthy event processing. Set up alerts for queue buildup.

Schema Evolution

When modifying event schemas, maintain backward compatibility. Add new optional fields rather than modifying existing ones.

Troubleshooting

Messages Not Being Consumed

Verify the queue exists and is bound to the correct exchange
Check the routing key matches the binding pattern
Ensure the consumer service is running and connected to RabbitMQ
Review consumer logs for exceptions

High Queue Depth

Check if consumers are processing messages slowly
Scale up the number of consumer instances
Investigate if messages are being rejected and requeued
Review message sizes and processing complexity

Use the RabbitMQ Management UI at http://localhost:15672 to monitor queues, exchanges, and message flows in real-time.

Microservices

API Reference

Event Overview

ProductSoldInternalEvent

Event Schema

Fields

Message Configuration

Event Example

Event Flow

ProductCreatedInternalEvent

Event Schema

Fields

Message Configuration

Event Example

AlertInternalEvent

Event Schema

Fields

Message Configuration

Event Example

Consumers

RabbitMQ Configuration

Exchanges

Queues

Message Serialization

Event Publishing

From Orders Service

From Sentinel Service

Event Consumption

Listening to Sales Events

Listening to Alert Events

Best Practices

Troubleshooting

Messages Not Being Consumed

High Queue Depth

Build docs developers (and LLMs) love

Microservices

API Reference

​Event Overview

​ProductSoldInternalEvent

​Event Schema

​Fields

​Message Configuration

​Event Example

​Event Flow

​ProductCreatedInternalEvent

​Event Schema

​Fields

​Message Configuration

​Event Example

​AlertInternalEvent

​Event Schema

​Fields

​Message Configuration

​Event Example

​Consumers

​RabbitMQ Configuration

​Exchanges

​Queues

​Message Serialization

​Event Publishing

​From Orders Service

​From Sentinel Service

​Event Consumption

​Listening to Sales Events

​Listening to Alert Events

​Best Practices

​Troubleshooting

​Messages Not Being Consumed

​High Queue Depth

Build docs developers (and LLMs) love

Event Overview

ProductSoldInternalEvent

Event Schema

Fields

Message Configuration

Event Example

Event Flow

ProductCreatedInternalEvent

Event Schema

Fields

Message Configuration

Event Example

AlertInternalEvent

Event Schema

Fields

Message Configuration

Event Example

Consumers

RabbitMQ Configuration

Exchanges

Queues

Message Serialization

Event Publishing

From Orders Service

From Sentinel Service

Event Consumption

Listening to Sales Events

Listening to Alert Events

Best Practices

Troubleshooting

Messages Not Being Consumed

High Queue Depth