key-value-data-store

A file-based key-value data store that supports the basic CRUD (create, read, update and delete) operations.

This data store is meant to be used as a local storage for one single process on one laptop. The data store must be exposed as a library to clients that can instantiate a class and work with the data store. The data store will support the following functional requirements.

1. create() : Takes the key input and checks whether the key is present is in file. If the key is present, then the key-value is created and inserted.
2. read() : Takes the key input and checks whether the key is present is in file. If the key is present, then the corresponding value is returned.
3. delete() : Takes the key input and checks whether the key is present is in file. If the key is present, then the key-value is deleted from the file.
4. update() : Takes the key input and checks whether the key is present is in file. If the key is present, then the value is modified and updated accordingly.

The data store will also support the following non-functional requirements.

1. The size of the file storing data must never exceed 1GB.
2. More than one client process cannot be allowed to use the same file as a data store at any given time.
3. A client process is allowed to access the data store using multiple threads, if it desires to. The data store must therefore be thread-safe.
4. The client will bear as little memory costs as possible to use this data store, while deriving maximum performance with respect to response times for accessing the data store.

Languages used:

Python

libraries used:

1. threading-Thread
2. json
3. sys
4. os
5. time
6. pathlib-Path