Created
June 22, 2020 11:00
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Event Sourcing Concepts
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| import json | |
| class EventStore: | |
| base_location = 'events' | |
| storage_format = 'jsonl' | |
| @classmethod | |
| def _get_event_storage_path(cls, key): | |
| event_storage_path = f'{cls.base_location}/{key}.{cls.storage_format}' | |
| return event_storage_path | |
| @classmethod | |
| def insert(cls, key, event): | |
| event_storage_path = cls._get_event_storage_path(key) | |
| with open(event_storage_path, 'a') as storage: | |
| json.dump(event, storage) | |
| storage.write('\n') | |
| @classmethod | |
| def get(cls, key): | |
| event_storage_path = cls._get_event_storage_path(key) | |
| with open(event_storage_path, 'r') as storage: | |
| events = [json.loads(event) for event in storage] | |
| return events | |
| class ProjectAccountBalance: | |
| def __init__(self, event_store: EventStore): | |
| self.event_store = event_store | |
| def get_balance(self, user_id: str): | |
| events = self.event_store.get(key=user_id) | |
| balance = sum( | |
| event['amount'] for event in events | |
| ) | |
| return balance | |
| def main(): | |
| print('Starting...') | |
| key = 'user_1' | |
| event = { | |
| 'operation': 'deposit', | |
| 'amount': 50.0 | |
| } | |
| account = ProjectAccountBalance( | |
| event_store=EventStore | |
| ) | |
| EventStore.insert(key, event) | |
| print(account.get_balance(key)) | |
| print('Closing...') | |
| if __name__ == "__main__": | |
| main() |
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