Microservices patterns

class MockLegacySystem:
    """Simulates a legacy system with messy data formats."""
    def get_user_data(self):
        # Legacy format: fields are abbreviated and types are inconsistent
        return {
            "usr_id": "USR-123",
            "usr_nm": "john_doe",
            "email_addrs": "John.Doe@example.c…

import json
from dataclasses import dataclass, asdict
from typing import List, Optional
from enum import Enum


class SagaStatus(Enum):
    PENDING = "PENDING"
    COMPLETING = "COMPLETING"
    COMPLETED = "COMPLETED"
    FAILED = "FAILED"


@dataclass
class EventEnvelope:
    event_type: str
    order_id: str
    sta…