Made the service into a daemon that you can route IPC commands to

main.go

@@ -1,65 +1,112 @@
 package main
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
+	"io"
 	"log"
+	"net/http"
+	"net/url"
 	"os"
-	"os/signal"
 	"path/filepath"
-	"syscall"
 )
 
 func main() {
-	fmt.Println("Initializing VS server manager...")
-
 	home, err := os.UserHomeDir()
 	if err != nil {
-		log.Fatalf("Could not locate user home dir")
+		log.Fatalf("Could not locate user home dir: %v", err)
 	}
 
 	configPath := filepath.Join(home, ".config", "vs-manager", "config.json")
-
 	cfg, err := LoadOrCreateConfig(configPath)
 	if err != nil {
 		log.Fatalf("Initialization failed: %v", err)
 	}
 
-	instanceName := "sample_server"
-	targetVersion := "1.22.3"
-
-	options := VsServerConfigOptions{
-		ServerName: "Sample Server",
-		Port:       4000,
-		MaxClients: 100,
-		Password:   "",
+	if len(os.Args) < 2 {
+		printUsage()
+		return
 	}
 
-	err = DownloadAndExtractServer(targetVersion, cfg.Storage.InstallDir)
-	if err != nil {
-		log.Fatalf("Downloader module encountered an error: %v", err)
+	subCommand := os.Args[1]
+
+	switch subCommand {
+	case "daemon":
+		fmt.Println("Initializing VS server manager background supervisor...")
+		if err := StartDaemon(cfg); err != nil {
+			log.Fatalf("Daemon runtime fatal error: %v", err)
+		}
+
+	case "create":
+		if len(os.Args) < 4 {
+			log.Fatalf("Usage: go run . create <instance_name> <version>")
+		}
+		name := os.Args[2]
+		version := os.Args[3]
+		sendIPCRequest(cfg, "POST", fmt.Sprintf("/instances/create?name=%s&version=%s", url.QueryEscape(name), url.QueryEscape(version)), nil)
+
+	case "start":
+		if len(os.Args) < 3 {
+			log.Fatalf("Usage: go run . start <instance_name>")
+		}
+		name := os.Args[2]
+		sendIPCRequest(cfg, "POST", fmt.Sprintf("/instances/start?name=%s", url.QueryEscape(name)), nil)
+
+	case "stop":
+		if len(os.Args) < 3 {
+			log.Fatalf("Usage: go run . stop <instance_name>")
+		}
+		name := os.Args[2]
+		sendIPCRequest(cfg, "POST", fmt.Sprintf("/instances/stop?name=%s", url.QueryEscape(name)), nil)
+
+	case "cmd":
+		if len(os.Args) < 4 {
+			log.Fatalf("Usage: go run . cmd <instance_name> \"<server command>\"")
+		}
+		name := os.Args[2]
+		serverCmd := os.Args[3]
+
+		payload := CommandPayload{Command: serverCmd}
+		body, _ := json.Marshal(payload)
+		sendIPCRequest(cfg, "POST", fmt.Sprintf("/instances/command?name=%s", url.QueryEscape(name)), bytes.NewBuffer(body))
+
+	default:
+		printUsage()
 	}
-
-	err = CreateNewInstance(instanceName, targetVersion, options, cfg)
-	if err != nil {
-		log.Fatalf("Initialization abort: %v", err)
-	}
-
-	procManager := NewProcessManager()
-
-	fmt.Printf("\n⚡ Launching Instance: %s (v%s)\n", instanceName, targetVersion)
-	err = procManager.StartInstance(instanceName, targetVersion, options, cfg)
-	if err != nil {
-		log.Fatalf("Process startup failed: %v", err)
-	}
-
-	sigChan := make(chan os.Signal, 1)
-	signal.Notify(sigChan, os.Interrupt, syscall.SIGTERM)
-
-	fmt.Println("\nServer running. Press Ctrl+C to cleanly shut down...")
-	<-sigChan
-
-	fmt.Println("\n\nTriggering graceful server termination sequence...")
-	_ = procManager.SendCommand(instanceName, "stop")
-
-	fmt.Println("Manager exited successfully.")
+}
+
+func sendIPCRequest(cfg *AppConfig, method string, path string, body io.Reader) {
+	targetUrl := fmt.Sprintf("http://%s%s", cfg.Daemon.ListenAddress, path)
+	req, err := http.NewRequest(method, targetUrl, body)
+	if err != nil {
+		log.Fatalf("Failed to construct IPC frame: %v", err)
+	}
+
+	if body != nil {
+		req.Header.Set("Content-Type", "application/json")
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		log.Fatalf("IPC connection failed. Is the vs-manager daemon running? Error: %v", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, _ := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		log.Fatalf("Error from daemon: %s", string(respBody))
+	}
+
+	fmt.Println(string(respBody))
+}
+
+func printUsage() {
+	fmt.Println("Vintage Story Server Manager")
+	fmt.Println("\nUsage:")
+	fmt.Println("  go run . daemon                      Starts the background process supervisor")
+	fmt.Println("  go run . create <name> <version>     Provisions baseline configuration and stores instance profile")
+	fmt.Println("  go run . start <name>                Launches an existing server instance using stored profile")
+	fmt.Println("  go run . stop <name>                 Gracefully shuts down a server instance")
+	fmt.Println("  go run . cmd <name> \"<command>\"     Dispatches a terminal console command down the pipe")
 }