┌───────────────┐ ┌───────────────────────┐ ┌───────────────┐ │ New Microservice│──────▶│ Anti-Corruption Layer │──────▶│ Legacy System │ └───────────────┘ └───────────────────────┘ └───────────────┘
This diagram shows the new microservice communicating only with the anti-corruption layer, which in turn interacts with the legacy system, preventing direct coupling.
### Before: Direct legacy coupling class LegacySystem: def get_user_data(self, user_id): # Returns data in legacy format return {'usr_id': user_id, 'nm': 'John Doe', 'addr': '123 St'} class NewService: def __init__(self, legacy): self.legacy = legacy def get_user_profile(self, user_id): data = self.legacy.get_user_data(user_id) # Directly uses legacy keys return f"User {data['nm']} lives at {data['addr']}" ### After: Using Anti-Corruption Layer class LegacySystem: def get_user_data(self, user_id): return {'usr_id': user_id, 'nm': 'John Doe', 'addr': '123 St'} class AntiCorruptionLayer: def __init__(self, legacy): self.legacy = legacy def get_user_profile(self, user_id): legacy_data = self.legacy.get_user_data(user_id) # Translate legacy data to clean model return { 'id': legacy_data['usr_id'], 'name': legacy_data['nm'], 'address': legacy_data['addr'] } class NewService: def __init__(self, acl): self.acl = acl def get_user_profile(self, user_id): profile = self.acl.get_user_profile(user_id) return f"User {profile['name']} lives at {profile['address']}"