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The CQRS and Event Sourcing framework for Python

Project description

# Kant Framework
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A CQRS and Event Sourcing framework, safe for humans.

## Feature Support

* Event Store
* Optimistic concurrency control
* JSON serialization
* SQLAlchemy Projections
* Snapshots **[IN PROGRESS]**

Kant officially supports Python 3.5-3.6.

## Getting started

Create declarative events

```python
from kant import events

class BankAccountCreated(events.Event):
id = events.CUIDField(primary_key=True)
owner = events.CharField()

class DepositPerformed(events.Event):
amount = events.DecimalField()
```

Create aggregate to apply events

```python
from kant import aggregates

class BankAccount(aggregates.Aggregate):
id = aggregates.CUIDField()
owner = aggregates.CharField()
balance = aggregates.DecimalField()

def apply_bank_account_created(self, event):
self.id = event.id
self.owner = event.owner
self.balance = 0

def apply_deposit_performed(self, event):
self.balance += event.amount
```

Now, save the events

```python
from kant.eventstore import connect

await connect(user='user', password='user', database='database')

# create event store for bank_account
conn.create_keyspace('bank_account')

# create events
bank_account_created = BankAccountCreated(
id=123,
owner='John Doe',
)
deposit_performed = DepositPerformed(
amount=20,
)

bank_account = BankAccount()
bank_account.dispatch([bank_account_created, deposit_performed])
bank_account.save()

stored_bank_account = BankAccount.objects.get(123)
```

## Installing
To install Kant, simply use [pipenv](pipenv.org) (or pip)

```bash
$ pipenv install kant
```



## Contributing

Please, read the contribute guide [CONTRIBUTING](CONTRIBUTING.md).

Project details


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