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lich make event

Create event classes for event-driven architecture.

What are Events?

Events represent things that happened:

  • UserRegistered
  • OrderPlaced
  • PaymentCompleted

Events are published and listeners react to them.

Usage

lich make event <Name>

Example

$ lich make event OrderPlaced

✅ Event OrderPlaced created!

Files created:
  backend/internal/events/order_placed.py

Generated Code

"""
OrderPlaced event.
"""
from dataclasses import dataclass
from datetime import datetime
from uuid import UUID


@dataclass
class OrderPlacedEvent:
    """
    Event emitted when an order is placed.
    """

    order_id: UUID
    user_id: UUID
    total: float
    timestamp: datetime = None

    def __post_init__(self):
        if self.timestamp is None:
            self.timestamp = datetime.utcnow()

Publishing Events

from internal.events.order_placed import OrderPlacedEvent

# In your service
event = OrderPlacedEvent(
    order_id=order.id,
    user_id=order.user_id,
    total=order.total
)

await event_bus.publish(event)

Why Events?

Benefit Description
🔌 Decoupling Services don't know about each other
📬 Async Non-blocking operations
🔄 Scalable Add listeners without changing code

See Also