Key Value DB (Redis v0.0.1) in Go

This repository is a reference implementation of the problem statement available at https://playbook.one2n.in/go-bootcamp/go-projects/key-value-db-redis-in-go/key-value-db-redis-exercise. The solution is a command-line utility that allows you to interact with a simple in-memory key-value database through a TCP server. It provides a command-line interface for executing various commands and retrieving results.

Installation

You must have Go(1.18) installed on your machine to use the CLI tool. Follow the steps below to install and set up the tool:

1. Clone the repository or download the source code files.

2. Open a terminal and navigate to the project directory.

3. Run the following command to build the CLI tool:

   go build -o kvdb

   This will create an executable file named kvdb in the project directory.

4. Optionally, you can move the kvdb executable to a directory in your system's PATH environment variable for easier access.

Usage

To start the TCP server and use the CLI tool, follow these steps:

1. Create a .env file in the root directory and set the desired values to the below environment variables. We have provided a .env.example file in the root directory for reference.

   1. Ensure the environment variable APP_PORT is set to the desired port number on which the TCP server should listen. For example, you can set it to 9736 by running:

      export APP_PORT=9736

      Replace 9736 with the desired port number.

   2. Optionally, set the environment variable to specify the number of in-memory databases (DB_COUNT). For example:

      export DB_COUNT=16

      Replace 16 with the desired number of databases. If not set, the default value is 16.

2. Run the following command to start the TCP server:

   ./kvdb

   Replace ./kvdb with the actual path to the kvdb executable if it's not in the current directory or your PATH.

3. The TCP server will start and display a message indicating it listens on the specified port.

4. Open another terminal and use a tool like nc to connect to the TCP server. For example:

   nc localhost 9736

   Replace localhost with the appropriate host if the server runs on a different machine and 9736 with the correct port number.

5. Once connected, you can interact with the CLI tool by entering commands. A $ symbol denotes the command prompt.

6. The available commands are case-insensitive and can be entered in the following format:

   COMMAND [argument1] [argument2] ...
   

   Replace COMMAND with a supported command and provide the necessary arguments.

7. The CLI tool supports the following commands:

   • SET key value: Sets the value of the specified key in the current database.
   • GET key: Retrieves the value of the specified key from the current database.
   • DEL key: Deletes the specified key from the current database.
   • INCR key: Increments the value of the specified key by 1.
   • INCRBY key increment: Increments the value of the specified key by the specified increment.
   • MULTI: Starts a transaction block.
   • EXEC: Executes all commands in a transaction block.
   • DISCARD: Discards all commands in a transaction block.
   • COMPACT: Compacts the database by removing expired keys.
   • SELECT index: Switches to the specified database index (0-based).

   Replace key, value, index, and increment with the appropriate values.

8. After entering a command, the CLI tool will display the command result. If the result is a list, each item will be numbered.

9. To exit the CLI tool, close the nc connection or terminate the terminal session.

Dependencies

The CLI tool depends on the following external packages:

• github.com/joho/godotenv: Used for loading environment variables from a .env file.

Make sure to install these dependencies using a package manager like go get or by including them in your Go module dependencies.

License

This project is licensed under the MIT License