hashdb

README

keev

keev is a simple key-value store built on top of hash tables using Go. Clients communicate with the server using gRPC and Google Protocol Buffers (protobufs). Data persist to disk and saving occurs every 5 minutes.

Architecture

High-level overview:

             ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
                                  Clients
             └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘
                                    ▲
                                    │
                                    │ Google Protocol Buffers
                                    │
                                    ▼
             ┌───────────────────────────────────────────────┐
             │                    gRPC                       │
             └───────────────────────────────────────────────┘
             ┌───────────────────────────────────────────────┐
             │                 RAM or disk                   │
             └───────────────────────────────────────────────┘

Database current accepts the following commands:

• SET key value (valid if key is not present)
• UPDATE key value (valid if key is present)
• HAS key
• UNSET key
• GET key
• COUNT
• SHOW KEYS
• SHOW DATA
• SHOW NAMESPACES
• USE namespace

Restrictions:

• Both key and value cannot contain spaces.
• key cannot contain dots.
• Only alphanumeric characters are allowed for namespace

Usage

1. Generate certificates for RPC: go run generate_cert.go --host=localhost

2. Change JWTSigningToken in common/jwt.go.

3. Define a list of users in data/users.json. Sample:

   [
     {
       "username": "admin",
       "password": "admin123",
       "perms": ["ADMIN"]
     },
     {
       "username": "user",
       "password": "user123",
       "perms": []
     }
   ]
   

Server: ./server Client: ./client --username="user" --password="user123"

Program

Server

Client

Future work?

• Permissions for users
• Tests
• Logs
• Own SQL-like syntax with lexer and parser
• Transactions
• Support for various types: numbers, etc.
• Drivers for other languages
• Scaling/fault-tolerant system using Raft/Paxos