bernardkissi / python_cache

Simple implementation of Cache system

PYTHON CACHE IMPLEMENTATION

Simple implementation of Cache system

CACHE METHODS

1.Get: retrieves information from redis cache

2.Set: set data into the redis cache

CACHE FUNCTIONS (SET & GET DATA INTO CACHE)

To use the cache class

from cache import Cache

cache: Cache = Cache()

ADDING DATA TO CACHE

To add data to the cache use the set method on the cache instance.

Method Signature

cache.set('key', data, expiryTime)

Example 1

cache.set('Product:2', {"name": "sneakers", "price": 200}, 30)

GETTING DATA FROM CACHE

To get data from the cache use the get method on the cache instance.

Method Signature

cache.get('key', callback, expiryTime)

scenario 1: when cache key exist

product1 = cache.get('Product:2')
print("Product fetched from cache", product1)

scenario 2: when cache key does not exist we make a call to DB/API

def fetchFromDB():
    with open('database.json') as db:
        data = db.read()
        results = json.loads(data)
        return results

callback is passed to the get method and the duration is set when callback data is set in cache

user1 = cache.get('User:1', fetchFromDB, 30)
print("User fetched from cache", user1)

BACKUP AND RESTORE

I used pub/sub of redis to listen for any changes in data and react accordingly

subscriber = Subscriber()
publisher = Publisher()

publisher.writeMessage({'name': "something new"})
payload = subscriber.getMessage()
print(payload)

this prints new data we publish to the console and the subscriber listen to this channel and create a backup for the current cache data