feat(main): add --port/-p flag for custom port configuration

db/config.go

@@ -19,13 +19,18 @@ type Config struct {
 
 	// MaxMemory is the maximum memory limit in bytes. 0 means unlimited.
 	MaxMemory int64
+
+	// Port is the TCP port the server is listening on. Set once at startup from
+	// the --port flag; read-only at runtime (changing it would require a rebind).
+	Port int
 }
 
 // ServerConfig is the package-level config instance used across the server.
 var ServerConfig = &Config{
 	Hz:                  1,
 	ActiveExpireEnabled: true,
 	MaxMemory:           0,
+	Port:                6378,
 }
 
 // CleanupInterval returns the active expiry ticker interval derived from Hz.
@@ -50,6 +55,8 @@ func (c *Config) Get(param string) (string, bool) {
 		return boolToYesNo(c.ActiveExpireEnabled), true
 	case "maxmemory":
 		return itoa64(c.MaxMemory), true
+	case "port":
+		return itoa(c.Port), true
 	}
 	return "", false
 }

docs/config.md

@@ -29,11 +29,12 @@ CONFIG SET parameter value
 
 ## Supported parameters
 
-| Parameter               | Type    | Default | Description                                              |
-|-------------------------|---------|---------|----------------------------------------------------------|
-| `hz`                    | integer | `1`     | Number of active expiry cycles per second. Must be > 0.  |
-| `active-expire-enabled` | yes/no  | `yes`   | Enable or disable the active expiry background job.      |
-| `maxmemory`             | integer | `0`     | Max memory in bytes. `0` means unlimited.                |
+| Parameter               | Type    | Default | Writable | Description                                              |
+|-------------------------|---------|---------|----------|----------------------------------------------------------|
+| `hz`                    | integer | `1`     | yes      | Number of active expiry cycles per second. Must be > 0.  |
+| `active-expire-enabled` | yes/no  | `yes`   | yes      | Enable or disable the active expiry background job.      |
+| `maxmemory`             | integer | `0`     | yes      | Max memory in bytes. `0` means unlimited.                |
+| `port`                  | integer | `6378`  | no       | TCP port the server is listening on. Set via `--port` flag at startup. |
 
 ## Return value
 
@@ -74,4 +75,8 @@ maxmemory
 
 > CONFIG SET maxmemory 1073741824
 OK
+
+> CONFIG GET port
+port
+6378
 ```

main.go

@@ -3,15 +3,23 @@ package main
 import (
 	"HelixDB/db"
 	"HelixDB/resp"
+	"flag"
 	"fmt"
 	"net"
 	"os"
 )
 
 func main() {
-	l, err := net.Listen("tcp", "0.0.0.0:6378")
+	port := flag.Int("port", 6378, "Port to listen on")
+	flag.IntVar(port, "p", *port, "Port to listen on (shorthand)")
+	flag.Parse()
+
+	db.ServerConfig.Port = *port
+
+	addr := fmt.Sprintf("0.0.0.0:%d", *port)
+	l, err := net.Listen("tcp", addr)
 	if err != nil {
-		fmt.Println("Failed to bind to port 6378")
+		fmt.Printf("Failed to bind to port %d\n", *port)
 		os.Exit(1)
 	}
 	defer l.Close()