- Handle Ctrl+C signal to graceful shutdown

- Update readme.md
- Implement test cases for storage

README.md

@@ -1,14 +1,13 @@
 # Key Value DB (Redis v0.0.1) in Go
 
-This readme file provides an overview and instructions for using the keyvaluedb CLI tool written in Golang.
-
+This repository serves as a reference implementation for the problem statement described [here](https://playbook.one2n.in/Key-Value-DB-Redis-exercise).
 ## Description
 
 The CLI tool is a key-value database (KVDB) that allows users to interact with a simple in-memory database through a TCP server. It provides a command-line interface for executing various commands and retrieving results.
 
 ## Installation
 
-To use the CLI tool, you need to have Golang(1.18) installed on your machine. Follow the steps below to install and set up the tool:
+To use the CLI tool, you need to have Go(1.18) installed on your machine. 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.
@@ -26,51 +25,54 @@ To use the CLI tool, you need to have Golang(1.18) installed on your machine. Fo
 
 To start the TCP server and use the CLI tool, follow these steps:
 
-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:
 
-   ```shell
-   export APP_PORT=9736
-   ```
+1. Create `.env` file in the root directory and set the desired values to the below environment variables. We have provided a `.env.example` file for reference.
 
-   Replace `9736` with the desired port number.
+   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:
 
-2. Optionally, if you want to specify the number of in-memory databases (`DB_COUNT`), set the environment variable as well. For example:
+      ```shell
+      export APP_PORT=9736
+      ```
 
-   ```shell
-   export DB_COUNT=16
-   ```
+      Replace `9736` with the desired port number.
+
+   2. Optionally, if you want to specify the number of in-memory databases (`DB_COUNT`), set the environment variable as well. For example:
+
+      ```shell
+      export DB_COUNT=16
+      ```
 
-   Replace `16` with the desired number of databases. If not set, the default value is `16`.
+      Replace `16` with the desired number of databases. If not set, the default value is `16`.
 
-3. Run the following command to start the TCP server:
+2. Run the following command to start the TCP server:
 
    ```shell
    ./kvdb
    ```
 
    Replace `./kvdb` with the actual path to the `kvdb` executable if it's not in the current directory or not in your `PATH`.
 
-4. The TCP server will start and display a message indicating that it is listening on the specified port.
+3. The TCP server will start and display a message indicating that it is listening on the specified port.
 
-5. Open another terminal or use a tool like `nc` to connect to the TCP server. For example:
+4. Open another terminal or use a tool like `nc` to connect to the TCP server. For example:
 
    ```shell
    nc localhost 9736
    ```
 
    Replace `localhost` with the appropriate host if the server is running on a different machine, and `9736` with the correct port number.
 
-6. Once connected, you can start interacting with the CLI tool by entering commands. The command prompt is denoted by a `$` symbol.
+5. Once connected, you can start interacting with the CLI tool by entering commands. The command prompt is denoted by a `$` symbol.
 
-7. The available commands are case-insensitive and can be entered in the following format:
+6. The available commands are case-insensitive and can be entered in the following format:
 
    ```
    COMMAND [argument1] [argument2] ...
    ```
 
    Replace `COMMAND` with one of the supported commands and provide the necessary arguments.
 
-8. The CLI tool supports the following commands:
+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.
@@ -85,9 +87,9 @@ To start the TCP server and use the CLI tool, follow these steps:
 
     Replace key, value, index, and increment with the appropriate values.
 
-9. After entering a command, the CLI tool will display the result of the command. If the result is a list, each item will be numbered.
+8. After entering a command, the CLI tool will display the result of the command. If the result is a list, each item will be numbered.
 
-10. To exit the CLI tool, close the `nc` connection or terminate the terminal session.
+9. To exit the CLI tool, close the `nc` connection or terminate the terminal session.
 
 ## Dependencies
 

domain/keyvaluedb.go

@@ -19,19 +19,19 @@ func NewKeyValueDB(storage storage.Storage) KeyValueDB {
 func (kvdb *KeyValueDB) Execute(dbIndex int, cmd Command) (int, interface{}) {
 	_, err := cmd.Validate()
 	if err != nil {
-		return 0, err.Error()
+		return dbIndex, err.Error()
 	}
 
 	if kvdb.isMultiBlockStarted && !cmd.isTerminatorCmd() {
 		kvdb.enqueue(cmd)
-		return 0, "QUEUED"
+		return dbIndex, "QUEUED"
 	}
 
 	switch cmd.Name {
 	case SELECT:
 		dbIndex, err = kvdb.storage.Select(cmd.Key)
 		if err != nil {
-			return 0, err.Error()
+			return dbIndex, err.Error()
 		}
 		return dbIndex, "OK"
 	case MULTI:

main.go

@@ -8,12 +8,18 @@ import (
 	"log"
 	"net"
 	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 
 	"github.com/joho/godotenv"
 )
 
 func main() {
+
+	// Handle interrupt signal
+	handleInterruptSignal()
+
 	err := godotenv.Load()
 	if err != nil {
 		log.Fatal(err.Error())
@@ -42,6 +48,19 @@ func main() {
 	}
 }
 
+func handleInterruptSignal() {
+	// Create an interrupt channel to listen for the interrupt signal
+	interrupt := make(chan os.Signal, 1)
+	signal.Notify(interrupt, os.Interrupt, syscall.SIGTERM)
+
+	go func() {
+		<-interrupt
+		fmt.Println("Interrupt signal received. Gracefully stopping...")
+
+		os.Exit(0)
+	}()
+}
+
 func startTcpServer(port string) (net.Listener, error) {
 	listener, err := net.Listen("tcp", port)
 	if err != nil {