7. SISTEMA DE MENSAJERÍA Y NOTIFICACIONES

graph TB
    MICRO[MICROSERVICIOS EMISORES

    MS-Pagos, 
    MS-Autenticación

    MS-Datos-Cliente, etc.]
    
    KAFKA[KAFKA EVENT BUS

    Topic: notifications]
    
    MS_NOT[MS-NOTIFICACIONES

    Node.js + Worker Threads]
    
    MAIN[Main Thread

    • Consume Kafka

    • Enqueue jobs

    • Coordina workers]
    
    WORKERS[Worker Thread Pool

    • Email Workers

    • SMS Workers

    • Push Workers]
    
    subgraph "REDIS QUEUES"
        Q1[Redis Queue

        Email]
        Q2[Redis Queue

        SMS]
        Q3[Redis Queue

        Push]
    end
    
    subgraph "SERVICIOS EXTERNOS"
        EMAIL[Mailpit Dev /
Nodemailer Prod]
        SMS[Firebase Cloud
Messaging SMS]
        PUSH[Firebase Cloud
Messaging Push]
    end
    
    MICRO -->|Emit Event| KAFKA
    KAFKA -->|Consume Events| MS_NOT
    MS_NOT --> MAIN
    MAIN --> WORKERS
    WORKERS --> Q1
    WORKERS --> Q2
    WORKERS --> Q3
    
    Q1 --> EMAIL
    Q2 --> SMS
    Q3 --> PUSH
    
    style MICRO fill:#667eea,stroke:#333,color:#fff
    style KAFKA fill:#764ba2,stroke:#333,color:#fff
    style MS_NOT fill:#4caf50,stroke:#333,color:#fff
    style MAIN fill:#2196F3,stroke:#333,color:#fff
    style WORKERS fill:#ff9800,stroke:#333,color:#fff
        

graph TB
    MAIN[MS-NOTIFICACIONES

    Main Thread

    Consume Kafka → Enqueue jobs → Coordina workers]
    
    subgraph "WORKER THREAD POOL"
        W1[Worker 1

            Email Thread]
        W2[Worker 2

            Email Thread]
        W3[Worker 3

            SMS Thread]
        W4[Worker 4

            Push Thread]
    end
    
    PROCESS[Procesa 1000+ notificaciones/segundo]
    
    MAIN --> W1
    MAIN --> W2
    MAIN --> W3
    MAIN --> W4
    
    W1 --> PROCESS
    W2 --> PROCESS
    W3 --> PROCESS
    W4 --> PROCESS
    
    style MAIN fill:#667eea,stroke:#333,color:#fff
    style W1 fill:#4caf50,stroke:#333,color:#fff
    style W2 fill:#4caf50,stroke:#333,color:#fff
    style W3 fill:#ff9800,stroke:#333,color:#fff
    style W4 fill:#2196F3,stroke:#333,color:#fff
    style PROCESS fill:#764ba2,stroke:#333,color:#fff
        

graph TB
    QUEUE[REDIS QUEUE - Bull]
    
    P1[Priority 1 - CRITICAL

        Security Events


        • Login nuevo dispositivo

        • Cambio contraseña

        • Intento login fallido]
    
    P2[Priority 2 - HIGH

        Transactional Events

        • Transferencia exitosa

        • Transferencia fallida

        • Recepción de dinero]
    
    P3[Priority 3 - NORMAL

        Informational


        • Saldo bajo

        • Recordatorio pago]
    
    P4[Priority 4 - LOW

        Marketing

        • Promociones

        • Newsletter]
    
    QUEUE --> P1
    P1 -->|Procesado primero| P2
    P2 --> P3
    P3 -->|Procesado último| P4
    
    style QUEUE fill:#667eea,stroke:#333,color:#fff,stroke-width:3px
    style P1 fill:#f44336,stroke:#333,color:#fff
    style P2 fill:#ff9800,stroke:#333,color:#fff
    style P3 fill:#2196F3,stroke:#333,color:#fff
    style P4 fill:#9e9e9e,stroke:#333,color:#fff
        

sequenceDiagram
    participant U as Usuario
    participant PAG as MS-Pagos
    participant K as Kafka
Topic: notifications
    participant NOT as MS-Notificaciones
    participant DB as Database/Cache
    participant BULL as Bull Queue
    participant W as Workers
Email/SMS/Push
    participant EXT as Servicios Externos
Nodemailer/Firebase
    participant ES as Elasticsearch
Audit Logs
    
    U->>PAG: Completa transferencia
    PAG->>K: POST Event TRANSFER_COMPLETED
{userId, amount, recipient, priority: HIGH}
    K->>NOT: Consumer Group notification-service
    
    NOT->>NOT: Valida estructura del evento
    NOT->>DB: Consulta preferencias del usuario
    DB-->>NOT: Preferencias (respeta excepto seguridad)
    
    NOT->>BULL: Enqueue job: email-notifications
{template, to, data, priority: 2}
    NOT->>BULL: Enqueue job: sms-notifications
{to, message, priority: 2}
    NOT->>BULL: Enqueue job: push-notifications
{token, title, body, priority: 2}
    
    par Workers procesan en paralelo
        BULL->>W: Email Worker (Worker Thread)
        W->>W: Renderiza plantilla HTML (Handlebars)
        W->>EXT: Envía vía Nodemailer SMTP
        EXT-->>W: ✓ Enviado
        W->>DB: Registra resultado en DB
        W->>ES: Log para auditoría
    and
        BULL->>W: SMS Worker (Worker Thread)
        W->>EXT: Envía vía Firebase Cloud Messaging
        EXT-->>W: ✓ Enviado
        W->>DB: Registra resultado en DB
        W->>ES: Log para auditoría
    and
        BULL->>W: Push Worker (Worker Thread)
        W->>EXT: Envía vía Firebase Cloud Messaging
        EXT-->>W: ✓ Enviado
        W->>DB: Registra resultado en DB
        W->>ES: Log para auditoría
    end
    
    W->>BULL: Marca jobs como completed
    BULL->>NOT: Actualiza métricas en Prometheus
    
    Note over U,ES: Usuario recibe notificación
Tiempo total: < 30 segundos
        

templates/
├── emails/
│   ├── transfer-completed.hbs
│   ├── login-new-device.hbs
│   ├── password-changed.hbs
│   ├── low-balance-alert.hbs
│   └── payment-reminder.hbs
│
├── sms/
│   ├── transfer-completed.txt
│   ├── login-new-device.txt
│   └── otp-code.txt
│
└── layouts/
    ├── base-email.hbs  (Header + Footer común)
    └── transactional.hbs

Ejemplo: transfer-completed.hbs

<h1>Transferencia Exitosa</h1>
<p>Hola {{customerName}},</p>
<p>Tu transferencia de <strong>{{amount}}</strong> a 
   <strong>{{recipientName}}</strong> fue exitosa.</p>
<p>Detalles:</p>
<ul>
  <li>Monto: {{amount}}</li>
  <li>Destinatario: {{recipientName}}</li>
  <li>Cuenta: {{accountNumber}}</li>
  <li>Fecha: {{date}}</li>
</ul>
        

graph TB
    subgraph "Carga Baja < 100 notif/s"
        P1[Pod 1

            12 workers]
    end
    
    subgraph "Carga Media 100-500 notif/s"
        P2A[Pod 1

            12 workers]
        P2B[Pod 2

            12 workers]
    end
    
    subgraph "Carga Alta 500-1500 notif/s"
        P3A[Pod 1

            12 workers]
        P3B[Pod 2

            12 workers]
        P3C[Pod 3

            12 workers]
    end
    
    HPA["HPA (Horizontal Pod Autoscaler)"

            • Métrica: Queue length en Redis

            • Scale-up: > 1000 jobs pendientes

            • Scale-down: < 100 jobs pendientes

            • Min replicas: 2

            • Max replicas: 5]
    
    style P1 fill:#4caf50,stroke:#333,color:#fff
    style P2A fill:#ff9800,stroke:#333,color:#fff
    style P2B fill:#ff9800,stroke:#333,color:#fff
    style P3A fill:#f44336,stroke:#333,color:#fff
    style P3B fill:#f44336,stroke:#333,color:#fff
    style P3C fill:#f44336,stroke:#333,color:#fff
    style HPA fill:#667eea,stroke:#333,color:#fff
        

graph TB
    MICRO[MICROSERVICIOS

    MS-Pagos, 
    MS-Auth,
    MS-Datos-Cliente, 
    MS-Auditoría]
    
    KAFKA[KAFKA CLUSTER

        Topic: notifications

               5 partitions
               RF: 3]
    
    MS_NOT[MS-NOTIFICACIONES

    Node.js + Worker Threads]
    
    MAIN[Main Thread

    • Kafka Consumer

    • Job Enqueue

    • Worker Coordination]
    
    WORKERS[Worker Thread Pool

    12 Workers Total

    • 4 Email Workers

    • 4 SMS Workers

    • 4 Push Workers]
    
    subgraph "REDIS QUEUES - Bull"
        Q1[Redis Queue
Email
Bull Queue]
        Q2[Redis Queue
SMS
Bull Queue]
        Q3[Redis Queue
Push
Bull Queue]
    end
    
    subgraph "SERVICIOS EXTERNOS"
        EMAIL[Mailpit Dev /
Nodemailer Prod]
        SMS[Firebase Cloud
Messaging SMS]
        PUSH[Firebase Cloud
Messaging Push]
    end
    
    ES[ELASTICSEARCH
Audit Logs
Retention: 2 años]
    
    MICRO -->|Publish Events| KAFKA
    KAFKA -->|Consumer Group| MS_NOT
    MS_NOT --> MAIN
    MAIN --> WORKERS
    
    WORKERS --> Q1
    WORKERS --> Q2
    WORKERS --> Q3
    
    Q1 --> EMAIL
    Q2 --> SMS
    Q3 --> PUSH
    
    EMAIL --> ES
    SMS --> ES
    PUSH --> ES
    
    style MICRO fill:#667eea,stroke:#333,color:#fff
    style KAFKA fill:#764ba2,stroke:#333,color:#fff
    style MS_NOT fill:#4caf50,stroke:#333,color:#fff
    style MAIN fill:#2196F3,stroke:#333,color:#fff
    style WORKERS fill:#ff9800,stroke:#333,color:#fff
    style ES fill:#9c27b0,stroke:#333,color:#fff