magistrala/notifications

Notifications Service

The Notifications Service is responsible for sending email notifications when domain invitation events occur in the Magistrala platform.

Overview

This service listens to invitation events from the domains service and sends email notifications to users when:

• They are invited to join a domain (invitation.send)
• Someone accepts their domain invitation (invitation.accept)
• Someone rejects their domain invitation (invitation.reject)

The service uses gRPC to fetch user information from the users service and sends styled email notifications using SMTP.

Features

• Event-Driven: Listens to invitation events from the event store (NATS/RabbitMQ)
• gRPC Integration: Fetches user details (name, email) from the users service
• Beautiful Email Templates: Styled HTML email templates with Magistrala branding (#083662)
• Configurable: Email server settings and templates are fully configurable

Architecture

domains service → event store → notifications service → users service (gRPC)
                                         ↓
                                    SMTP Server → Email Recipients

Configuration

The service is configured using environment variables:

General Configuration

• MG_NOTIFICATIONS_LOG_LEVEL - Log level (default: "info")
• MG_NOTIFICATIONS_INSTANCE_ID - Instance ID for the service
• MG_NOTIFICATIONS_DOMAIN_ALT_NAME - Alternative name for domains such as, say, workspaces or tenants (default: "domains")
• MG_ES_URL - Event store URL (default: "nats://localhost:4222")

Email Configuration

• MG_EMAIL_HOST - SMTP server host (default: "localhost")
• MG_EMAIL_PORT - SMTP server port (default: "25")
• MG_EMAIL_USERNAME - SMTP username
• MG_EMAIL_PASSWORD - SMTP password
• MG_EMAIL_FROM_ADDRESS - From email address (default: "noreply@magistrala.com")
• MG_EMAIL_FROM_NAME - From name (default: "Magistrala Notifications")

Template Configuration

• MG_EMAIL_INVITATION_TEMPLATE - Path to invitation email template
• MG_EMAIL_ACCEPTANCE_TEMPLATE - Path to acceptance email template
• MG_EMAIL_REJECTION_TEMPLATE - Path to rejection email template

gRPC Configuration (Users Service)

• MG_USERS_GRPC_URL - Users service gRPC URL
• MG_USERS_GRPC_TIMEOUT - gRPC request timeout
• MG_USERS_GRPC_CLIENT_CERT - Client certificate path
• MG_USERS_GRPC_CLIENT_KEY - Client key path
• MG_USERS_GRPC_SERVER_CA_CERTS - Server CA certificates path

Running the Service

go run cmd/notifications/main.go

Or build and run:

go build -o notifications cmd/notifications/main.go
./notifications

Email Templates

The service includes three beautifully styled email templates with Magistrala branding:

1. Invitation Sent (invitation-sent-email.tmpl) - Blue gradient header (#083662)
2. Invitation Accepted (invitation-accepted-email.tmpl) - Green gradient header
3. Invitation Rejected (invitation-rejected-email.tmpl) - Red gradient header

All templates are responsive and include:

• Professional styling
• Gradient headers
• Clear call-to-action sections
• Magistrala branding

Testing

Run the tests:

go test ./notifications/... -v

To run email integration tests (requires SMTP server):

MG_RUN_EMAIL_TESTS=true go test ./notifications/emailer -v

Development

The service consists of:

• notifier.go - Main service interface
• emailer/emailer.go - Email notification implementation
• events/consumer.go - Event consumer for invitation events
• cmd/notifications/main.go - Service entry point
• Tests with mocks for unit testing

Dependencies

• Users service (gRPC) - for fetching user information
• Event store (NATS/RabbitMQ) - for receiving invitation events
• SMTP server - for sending emails