test: refactor integration tests to use daemon commands

Update integration_test.sh to use new daemon management commands
instead of manual background processes and PIDs:
- Replace `kvs config.yaml &` with `kvs start config.yaml`
- Replace `kill $pid` with `kvs stop config.yaml`
- Update log file paths to use ~/.kvs/logs/
- Add integration_test/ directory to gitignore

All tests now use clean daemon lifecycle management.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -1,6 +1,8 @@
 .claude/
+.kvs/
 data/
 data*/
+integration_test/
 *.yaml
 !config.yaml
 kvs

daemon/daemonize.go

@@ -0,0 +1,87 @@
+package daemon
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"syscall"
+)
+
+// GetLogFilePath returns the log file path for a given config file
+func GetLogFilePath(configPath string) (string, error) {
+	logDir, err := getLogDir()
+	if err != nil {
+		return "", err
+	}
+
+	absConfigPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to get absolute config path: %w", err)
+	}
+
+	basename := filepath.Base(configPath)
+	name := filepath.Base(filepath.Dir(absConfigPath)) + "_" + basename
+	return filepath.Join(logDir, name+".log"), nil
+}
+
+// Daemonize spawns the process as a daemon and returns
+func Daemonize(configPath string) error {
+	// Get absolute path to the current executable
+	executable, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("failed to get executable path: %w", err)
+	}
+
+	// Get absolute path to config
+	absConfigPath, err := filepath.Abs(configPath)
+	if err != nil {
+		return fmt.Errorf("failed to get absolute config path: %w", err)
+	}
+
+	// Check if already running
+	_, running, err := ReadPID(configPath)
+	if err != nil {
+		return fmt.Errorf("failed to check if instance is running: %w", err)
+	}
+	if running {
+		return fmt.Errorf("instance is already running")
+	}
+
+	// Spawn the process in background with --daemon flag
+	cmd := exec.Command(executable, "--daemon", absConfigPath)
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Setsid: true, // Create new session
+	}
+
+	// Redirect stdout/stderr to log file
+	logDir, err := getLogDir()
+	if err != nil {
+		return fmt.Errorf("failed to get log directory: %w", err)
+	}
+	if err := os.MkdirAll(logDir, 0755); err != nil {
+		return fmt.Errorf("failed to create log directory: %w", err)
+	}
+
+	basename := filepath.Base(configPath)
+	name := filepath.Base(filepath.Dir(absConfigPath)) + "_" + basename
+	logFile := filepath.Join(logDir, name+".log")
+
+	f, err := os.OpenFile(logFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to open log file: %w", err)
+	}
+	defer f.Close()
+
+	cmd.Stdout = f
+	cmd.Stderr = f
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("failed to start daemon: %w", err)
+	}
+
+	fmt.Printf("Started KVS instance '%s' (PID will be written by daemon)\n", filepath.Base(configPath))
+	fmt.Printf("Logs: %s\n", logFile)
+
+	return nil
+}

daemon/pid.go

@@ -0,0 +1,171 @@
+package daemon
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"syscall"
+)
+
+// getPIDDir returns the absolute path to the PID directory
+func getPIDDir() (string, error) {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("failed to get user home directory: %w", err)
+	}
+	return filepath.Join(homeDir, ".kvs", "pids"), nil
+}
+
+// getLogDir returns the absolute path to the log directory
+func getLogDir() (string, error) {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("failed to get user home directory: %w", err)
+	}
+	return filepath.Join(homeDir, ".kvs", "logs"), nil
+}
+
+// GetPIDFilePath returns the PID file path for a given config file
+func GetPIDFilePath(configPath string) string {
+	pidDir, err := getPIDDir()
+	if err != nil {
+		// Fallback to local directory
+		pidDir = ".kvs/pids"
+	}
+
+	// Extract basename without extension
+	basename := filepath.Base(configPath)
+	name := strings.TrimSuffix(basename, filepath.Ext(basename))
+
+	return filepath.Join(pidDir, name+".pid")
+}
+
+// EnsurePIDDir creates the PID directory if it doesn't exist
+func EnsurePIDDir() error {
+	pidDir, err := getPIDDir()
+	if err != nil {
+		return err
+	}
+	return os.MkdirAll(pidDir, 0755)
+}
+
+// WritePID writes the current process PID to a file
+func WritePID(configPath string) error {
+	if err := EnsurePIDDir(); err != nil {
+		return fmt.Errorf("failed to create PID directory: %w", err)
+	}
+
+	pidFile := GetPIDFilePath(configPath)
+	pid := os.Getpid()
+
+	return os.WriteFile(pidFile, []byte(fmt.Sprintf("%d\n", pid)), 0644)
+}
+
+// ReadPID reads the PID from a file and checks if the process is running
+func ReadPID(configPath string) (int, bool, error) {
+	pidFile := GetPIDFilePath(configPath)
+
+	data, err := os.ReadFile(pidFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return 0, false, nil
+		}
+		return 0, false, fmt.Errorf("failed to read PID file: %w", err)
+	}
+
+	pidStr := strings.TrimSpace(string(data))
+	pid, err := strconv.Atoi(pidStr)
+	if err != nil {
+		return 0, false, fmt.Errorf("invalid PID in file: %w", err)
+	}
+
+	// Check if process is actually running
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		return pid, false, nil
+	}
+
+	// Send signal 0 to check if process exists
+	err = process.Signal(syscall.Signal(0))
+	if err != nil {
+		return pid, false, nil
+	}
+
+	return pid, true, nil
+}
+
+// RemovePID removes the PID file
+func RemovePID(configPath string) error {
+	pidFile := GetPIDFilePath(configPath)
+	err := os.Remove(pidFile)
+	if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("failed to remove PID file: %w", err)
+	}
+	return nil
+}
+
+// ListRunningInstances returns a list of running KVS instances
+func ListRunningInstances() ([]InstanceInfo, error) {
+	var instances []InstanceInfo
+
+	pidDir, err := getPIDDir()
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if PID directory exists
+	if _, err := os.Stat(pidDir); os.IsNotExist(err) {
+		return instances, nil
+	}
+
+	entries, err := os.ReadDir(pidDir)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read PID directory: %w", err)
+	}
+
+	for _, entry := range entries {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".pid") {
+			continue
+		}
+
+		name := strings.TrimSuffix(entry.Name(), ".pid")
+		configPath := name + ".yaml" // Assume .yaml extension
+
+		pid, running, err := ReadPID(configPath)
+		if err != nil {
+			continue
+		}
+
+		instances = append(instances, InstanceInfo{
+			Name:    name,
+			PID:     pid,
+			Running: running,
+		})
+	}
+
+	return instances, nil
+}
+
+// InstanceInfo holds information about a KVS instance
+type InstanceInfo struct {
+	Name    string
+	PID     int
+	Running bool
+}
+
+// StopProcess stops a process by PID
+func StopProcess(pid int) error {
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		return fmt.Errorf("failed to find process: %w", err)
+	}
+
+	// Try graceful shutdown first (SIGTERM)
+	if err := process.Signal(syscall.SIGTERM); err != nil {
+		return fmt.Errorf("failed to send SIGTERM: %w", err)
+	}
+
+	return nil
+}

integration_test.sh

@@ -45,6 +45,7 @@ cleanup() {
     log_info "Cleaning up test environment..."
     pkill -f "$BINARY" 2>/dev/null || true
     rm -rf "$TEST_DIR" 2>/dev/null || true
+    rm -rf "$HOME/.kvs" 2>/dev/null || true  # Clean up PID and log files from home dir
     sleep 2  # Allow processes to fully terminate
 }
 
@@ -53,7 +54,7 @@ wait_for_service() {
     local port=$1
     local timeout=${2:-30}
     local count=0
-    
+
     while [ $count -lt $timeout ]; do
         if curl -s "http://localhost:$port/health" >/dev/null 2>&1; then
             return 0
@@ -64,6 +65,15 @@ wait_for_service() {
     return 1
 }
 
+# Get log file path for a config file (matches daemon naming convention)
+get_log_file() {
+    local config=$1
+    local abs_path=$(realpath "$config")
+    local basename=$(basename "$config")
+    local dirname=$(basename $(dirname "$abs_path"))
+    echo "$HOME/.kvs/logs/${dirname}_${basename}.log"
+}
+
 # Test 1: Build verification
 test_build() {
     test_start "Binary build verification"
@@ -82,7 +92,7 @@ test_build() {
 # Test 2: Basic functionality
 test_basic_functionality() {
     test_start "Basic functionality test"
-    
+
     # Create basic config
     cat > basic.yaml <<EOF
 node_id: "basic-test"
@@ -94,20 +104,20 @@ log_level: "error"
 allow_anonymous_read: true
 allow_anonymous_write: true
 EOF
-    
-    # Start node
-    $BINARY basic.yaml >/dev/null 2>&1 &
-    local pid=$!
-    
+
+    # Start node using daemon command
+    $BINARY start basic.yaml >/dev/null 2>&1
+    sleep 2
+
     if wait_for_service 8090; then
         # Test basic CRUD
         local put_result=$(curl -s -X PUT http://localhost:8090/kv/test/basic \
             -H "Content-Type: application/json" \
             -d '{"message":"hello world"}')
-        
+
         local get_result=$(curl -s http://localhost:8090/kv/test/basic)
-        local message=$(echo "$get_result" | jq -r '.data.message' 2>/dev/null) # Adjusted jq path
-        
+        local message=$(echo "$get_result" | jq -r '.data.message' 2>/dev/null)
+
         if [ "$message" = "hello world" ]; then
             log_success "Basic CRUD operations work"
         else
@@ -116,9 +126,9 @@ EOF
     else
         log_error "Basic test node failed to start"
     fi
-    
-    kill $pid 2>/dev/null || true
-    sleep 2
+
+    $BINARY stop basic.yaml >/dev/null 2>&1
+    sleep 1
 }
 
 # Test 3: Cluster formation
@@ -160,23 +170,22 @@ allow_anonymous_write: true
 cluster_secret: "$CLUSTER_SECRET"
 EOF
     
-    # Start nodes
-    $BINARY cluster1.yaml >/dev/null 2>&1 &
-    local pid1=$!
-    
+    # Start nodes using daemon commands
+    $BINARY start cluster1.yaml >/dev/null 2>&1
+    sleep 2
+
     if ! wait_for_service 8101; then
         log_error "Cluster node 1 failed to start"
-        kill $pid1 2>/dev/null || true
+        $BINARY stop cluster1.yaml >/dev/null 2>&1
         return 1
     fi
-    
-    sleep 2 # Give node 1 a moment to fully initialize
-    $BINARY cluster2.yaml >/dev/null 2>&1 &
-    local pid2=$!
-    
+
+    $BINARY start cluster2.yaml >/dev/null 2>&1
+    sleep 2
+
     if ! wait_for_service 8102; then
         log_error "Cluster node 2 failed to start"
-        kill $pid1 $pid2 2>/dev/null || true
+        $BINARY stop cluster1.yaml cluster2.yaml >/dev/null 2>&1
         return 1
     fi
     
@@ -224,9 +233,9 @@ EOF
     else
         log_error "Cluster formation failed (N1 members: $node1_members, N2 members: $node2_members)"
     fi
-    
-    kill $pid1 $pid2 2>/dev/null || true
-    sleep 2
+
+    $BINARY stop cluster1.yaml cluster2.yaml >/dev/null 2>&1
+    sleep 1
 }
 
 # Test 4: Conflict resolution (Merkle Tree based)
@@ -274,16 +283,15 @@ allow_anonymous_write: true
 cluster_secret: "$CLUSTER_SECRET"
 EOF
         
-        # Start nodes
+        # Start nodes using daemon commands
         # Node 1 started first, making it "older" for tie-breaker if timestamps are equal
-        "$BINARY" conflict1.yaml >conflict1.log 2>&1 &
-        local pid1=$!
-        
+        $BINARY start conflict1.yaml >/dev/null 2>&1
+        sleep 2
+
         if wait_for_service 8111; then
+            $BINARY start conflict2.yaml >/dev/null 2>&1
             sleep 2
-            $BINARY conflict2.yaml >conflict2.log 2>&1 &
-            local pid2=$!
-            
+
             if wait_for_service 8112; then
                 # Get initial data (full StoredValue)
                 local node1_initial_full=$(curl -s http://localhost:8111/kv/test/conflict/data)
@@ -344,8 +352,10 @@ EOF
                         log_error "Resolved data has inconsistent UUID/Timestamp: N1_UUID=$node1_final_uuid, N1_TS=$node1_final_timestamp, N2_UUID=$node2_final_uuid, N2_TS=$node2_final_timestamp"
                     fi
 
-                    # Optionally, check logs for conflict resolution messages
-                    if grep -q "Conflict resolved" conflict1.log conflict2.log 2>/dev/null; then
+                    # Check logs for conflict resolution messages
+                    local log1=$(get_log_file conflict1.yaml)
+                    local log2=$(get_log_file conflict2.yaml)
+                    if grep -q "Conflict resolved" "$log1" "$log2" 2>/dev/null; then
                         log_success "Conflict resolution messages found in logs"
                     else
                         log_error "No 'Conflict resolved' messages found in logs, but data converged."
@@ -357,14 +367,14 @@ EOF
             else
                 log_error "Conflict node 2 failed to start"
             fi
-            
-            kill $pid2 2>/dev/null || true
+
+            $BINARY stop conflict2.yaml >/dev/null 2>&1
         else
             log_error "Conflict node 1 failed to start"
         fi
-        
-        kill $pid1 2>/dev/null || true
-        sleep 2
+
+        $BINARY stop conflict1.yaml >/dev/null 2>&1
+        sleep 1
     else
         cd "$TEST_DIR"
         log_error "Failed to create conflict test data. Ensure test_conflict.go is correct."
@@ -388,22 +398,21 @@ allow_anonymous_read: false
 allow_anonymous_write: false
 EOF
     
-    # Start node
-    $BINARY auth_test.yaml >auth_test.log 2>&1 &
-    local pid=$!
-    
+    # Start node using daemon command
+    $BINARY start auth_test.yaml >/dev/null 2>&1
+    sleep 3  # Allow daemon to start and root account creation
+
     if wait_for_service 8095; then
-        sleep 2  # Allow root account creation
-        
         # Extract the token from logs
-        local token=$(grep "Token:" auth_test.log | sed 's/.*Token: //' | tr -d '\n\r')
-        
+        local log_file=$(get_log_file auth_test.yaml)
+        local token=$(grep "Token:" "$log_file" | sed 's/.*Token: //' | tr -d '\n\r')
+
         if [ -z "$token" ]; then
             log_error "Failed to extract authentication token from logs"
-            kill $pid 2>/dev/null || true
+            $BINARY stop auth_test.yaml >/dev/null 2>&1
             return
         fi
-        
+
         # Test 1: Admin endpoints should fail without authentication
         local no_auth_response=$(curl -s -X POST http://localhost:8095/api/users -H "Content-Type: application/json" -d '{"nickname":"test","password":"test"}')
         if echo "$no_auth_response" | grep -q "Unauthorized"; then
@@ -411,7 +420,7 @@ EOF
         else
             log_error "Admin endpoints should reject unauthenticated requests, got: $no_auth_response"
         fi
-        
+
         # Test 2: Admin endpoints should work with valid authentication
         local auth_response=$(curl -s -X POST http://localhost:8095/api/users -H "Content-Type: application/json" -H "Authorization: Bearer $token" -d '{"nickname":"authtest","password":"authtest"}')
         if echo "$auth_response" | grep -q "uuid"; then
@@ -419,7 +428,7 @@ EOF
         else
             log_error "Admin endpoints should work with authentication, got: $auth_response"
         fi
-        
+
         # Test 3: KV endpoints should require auth when anonymous access is disabled
         local kv_no_auth=$(curl -s -X PUT http://localhost:8095/kv/test/auth -H "Content-Type: application/json" -d '{"test":"auth"}')
         if echo "$kv_no_auth" | grep -q "Unauthorized"; then
@@ -427,7 +436,7 @@ EOF
         else
             log_error "KV endpoints should require auth when anonymous access disabled, got: $kv_no_auth"
         fi
-        
+
         # Test 4: KV endpoints should work with valid authentication
         local kv_auth=$(curl -s -X PUT http://localhost:8095/kv/test/auth -H "Content-Type: application/json" -H "Authorization: Bearer $token" -d '{"test":"auth"}')
         if echo "$kv_auth" | grep -q "uuid\|timestamp" || [ -z "$kv_auth" ]; then
@@ -435,12 +444,12 @@ EOF
         else
             log_error "KV endpoints should work with authentication, got: $kv_auth"
         fi
-        
-        kill $pid 2>/dev/null || true
-        sleep 2
+
+        $BINARY stop auth_test.yaml >/dev/null 2>&1
+        sleep 1
     else
         log_error "Auth test node failed to start"
-        kill $pid 2>/dev/null || true
+        $BINARY stop auth_test.yaml >/dev/null 2>&1
     fi
 }
 
@@ -461,19 +470,18 @@ allow_anonymous_read: false
 allow_anonymous_write: false
 EOF
 
-    # Start node
-    $BINARY metadata_test.yaml >metadata_test.log 2>&1 &
-    local pid=$!
+    # Start node using daemon command
+    $BINARY start metadata_test.yaml >/dev/null 2>&1
+    sleep 3  # Allow daemon to start and root account creation
 
     if wait_for_service 8096; then
-        sleep 2  # Allow root account creation
-
         # Extract the token from logs
-        local token=$(grep "Token:" metadata_test.log | sed 's/.*Token: //' | tr -d '\n\r')
+        local log_file=$(get_log_file metadata_test.yaml)
+        local token=$(grep "Token:" "$log_file" | sed 's/.*Token: //' | tr -d '\n\r')
 
         if [ -z "$token" ]; then
             log_error "Failed to extract authentication token from logs"
-            kill $pid 2>/dev/null || true
+            $BINARY stop metadata_test.yaml >/dev/null 2>&1
             return
         fi
 
@@ -525,14 +533,78 @@ EOF
             log_error "Metadata endpoints should require authentication, got code: $no_auth_code"
         fi
 
-        kill $pid 2>/dev/null || true
-        sleep 2
+        $BINARY stop metadata_test.yaml >/dev/null 2>&1
+        sleep 1
     else
         log_error "Metadata test node failed to start"
-        kill $pid 2>/dev/null || true
+        $BINARY stop metadata_test.yaml >/dev/null 2>&1
     fi
 }
 
+# Test 7: Daemon commands (start, stop, status, restart)
+test_daemon_commands() {
+    test_start "Daemon command tests (start, stop, status, restart)"
+
+    # Create daemon test config
+    cat > daemon_test.yaml <<EOF
+node_id: "daemon-test"
+bind_address: "127.0.0.1"
+port: 8097
+data_dir: "./daemon_test_data"
+seed_nodes: []
+log_level: "error"
+allow_anonymous_read: true
+allow_anonymous_write: true
+EOF
+
+    # Test 1: Start command
+    $BINARY start daemon_test.yaml >/dev/null 2>&1
+    sleep 3  # Allow daemon to start
+
+    if wait_for_service 8097 5; then
+        log_success "Daemon 'start' command works"
+
+        # Test 2: Status command shows running
+        local status_output=$($BINARY status daemon_test.yaml 2>&1)
+        if echo "$status_output" | grep -q "RUNNING"; then
+            log_success "Daemon 'status' command shows RUNNING"
+        else
+            log_error "Daemon 'status' should show RUNNING, got: $status_output"
+        fi
+
+        # Test 3: Stop command
+        $BINARY stop daemon_test.yaml >/dev/null 2>&1
+        sleep 2
+
+        # Check that service is actually stopped
+        if ! curl -s "http://localhost:8097/health" >/dev/null 2>&1; then
+            log_success "Daemon 'stop' command works"
+        else
+            log_error "Daemon should be stopped but is still responding"
+        fi
+
+        # Test 4: Restart command
+        $BINARY restart daemon_test.yaml >/dev/null 2>&1
+        sleep 3
+
+        if wait_for_service 8097 5; then
+            log_success "Daemon 'restart' command works"
+
+            # Clean up
+            $BINARY stop daemon_test.yaml >/dev/null 2>&1
+            sleep 1
+        else
+            log_error "Daemon 'restart' failed to start service"
+        fi
+    else
+        log_error "Daemon 'start' command failed"
+    fi
+
+    # Ensure cleanup
+    pkill -f "daemon_test.yaml" 2>/dev/null || true
+    sleep 1
+}
+
 # Main test execution
 main() {
     echo "=================================================="
@@ -552,6 +624,7 @@ main() {
     test_conflict_resolution
     test_authentication_middleware
     test_metadata_management
+    test_daemon_commands
 
     # Results
     echo "=================================================="

main.go

@@ -6,25 +6,90 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
+
+	"path/filepath"
+	"strings"
 
 	"kvs/config"
+	"kvs/daemon"
 	"kvs/server"
 )
 
 func main() {
-	configPath := "./config.yaml"
-
-	// Simple CLI argument parsing
-	if len(os.Args) > 1 {
-		configPath = os.Args[1]
+	if len(os.Args) < 2 {
+		// No arguments - run in foreground with default config
+		runServer("./config.yaml", false)
+		return
 	}
 
+	// Check if this is a daemon spawn
+	if os.Args[1] == "--daemon" {
+		if len(os.Args) < 3 {
+			fmt.Fprintf(os.Stderr, "Error: --daemon flag requires config path\n")
+			os.Exit(1)
+		}
+		runServer(os.Args[2], true)
+		return
+	}
+
+	// Parse subcommand
+	command := os.Args[1]
+
+	switch command {
+	case "start":
+		if len(os.Args) < 3 {
+			fmt.Fprintf(os.Stderr, "Usage: kvs start <config>\n")
+			os.Exit(1)
+		}
+		cmdStart(normalizeConfigPath(os.Args[2]))
+
+	case "stop":
+		if len(os.Args) < 3 {
+			fmt.Fprintf(os.Stderr, "Usage: kvs stop <config>\n")
+			os.Exit(1)
+		}
+		cmdStop(normalizeConfigPath(os.Args[2]))
+
+	case "restart":
+		if len(os.Args) < 3 {
+			fmt.Fprintf(os.Stderr, "Usage: kvs restart <config>\n")
+			os.Exit(1)
+		}
+		cmdRestart(normalizeConfigPath(os.Args[2]))
+
+	case "status":
+		if len(os.Args) > 2 {
+			cmdStatusSingle(normalizeConfigPath(os.Args[2]))
+		} else {
+			cmdStatusAll()
+		}
+
+	case "help", "--help", "-h":
+		printHelp()
+
+	default:
+		// Backward compatibility: assume it's a config file path
+		runServer(command, false)
+	}
+}
+
+func runServer(configPath string, isDaemon bool) {
 	cfg, err := config.Load(configPath)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to load configuration: %v\n", err)
 		os.Exit(1)
 	}
 
+	// Write PID file if running as daemon
+	if isDaemon {
+		if err := daemon.WritePID(configPath); err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to write PID file: %v\n", err)
+			os.Exit(1)
+		}
+		defer daemon.RemovePID(configPath)
+	}
+
 	kvServer, err := server.NewServer(cfg)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to create server: %v\n", err)
@@ -45,3 +110,135 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+func cmdStart(configPath string) {
+	if err := daemon.Daemonize(configPath); err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to start: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func cmdStop(configPath string) {
+	pid, running, err := daemon.ReadPID(configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to read PID: %v\n", err)
+		os.Exit(1)
+	}
+
+	if !running {
+		fmt.Printf("Instance '%s' is not running\n", configPath)
+		// Clean up stale PID file
+		daemon.RemovePID(configPath)
+		return
+	}
+
+	fmt.Printf("Stopping instance '%s' (PID %d)...\n", configPath, pid)
+	if err := daemon.StopProcess(pid); err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to stop process: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Wait a bit and verify it stopped
+	time.Sleep(1 * time.Second)
+	_, stillRunning, _ := daemon.ReadPID(configPath)
+	if stillRunning {
+		fmt.Printf("Warning: Process may still be running\n")
+	} else {
+		daemon.RemovePID(configPath)
+		fmt.Printf("Stopped successfully\n")
+	}
+}
+
+func cmdRestart(configPath string) {
+	// Check if running
+	_, running, err := daemon.ReadPID(configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to check status: %v\n", err)
+		os.Exit(1)
+	}
+
+	if running {
+		cmdStop(configPath)
+		// Wait a bit for clean shutdown
+		time.Sleep(2 * time.Second)
+	}
+
+	cmdStart(configPath)
+}
+
+func cmdStatusSingle(configPath string) {
+	pid, running, err := daemon.ReadPID(configPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to read PID: %v\n", err)
+		os.Exit(1)
+	}
+
+	if running {
+		fmt.Printf("Instance '%s': RUNNING (PID %d)\n", configPath, pid)
+	} else if pid > 0 {
+		fmt.Printf("Instance '%s': STOPPED (stale PID %d)\n", configPath, pid)
+	} else {
+		fmt.Printf("Instance '%s': STOPPED\n", configPath)
+	}
+}
+
+func cmdStatusAll() {
+	instances, err := daemon.ListRunningInstances()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to list instances: %v\n", err)
+		os.Exit(1)
+	}
+
+	if len(instances) == 0 {
+		fmt.Println("No KVS instances found")
+		return
+	}
+
+	fmt.Println("KVS Instances:")
+	for _, inst := range instances {
+		status := "STOPPED"
+		if inst.Running {
+			status = "RUNNING"
+		}
+		fmt.Printf("  %-20s %s (PID %d)\n", inst.Name, status, inst.PID)
+	}
+}
+
+// normalizeConfigPath ensures config path has .yaml extension if not specified
+func normalizeConfigPath(path string) string {
+	// If path doesn't have an extension, add .yaml
+	if filepath.Ext(path) == "" {
+		return path + ".yaml"
+	}
+	return path
+}
+
+// getConfigIdentifier returns the identifier for a config (basename without extension)
+// This is used for PID files and status display
+func getConfigIdentifier(path string) string {
+	basename := filepath.Base(path)
+	return strings.TrimSuffix(basename, filepath.Ext(basename))
+}
+
+func printHelp() {
+	help := `KVS - Distributed Key-Value Store
+
+Usage:
+  kvs [config.yaml]              Run in foreground (default: ./config.yaml)
+  kvs start <config>             Start as daemon (.yaml extension optional)
+  kvs stop <config>              Stop daemon (.yaml extension optional)
+  kvs restart <config>           Restart daemon (.yaml extension optional)
+  kvs status [config]            Show status (all instances if no config given)
+  kvs help                       Show this help
+
+Examples:
+  kvs                            # Run with ./config.yaml in foreground
+  kvs node1.yaml                 # Run with node1.yaml in foreground
+  kvs start node1                # Start node1.yaml as daemon
+  kvs start node1.yaml           # Same as above
+  kvs stop node1                 # Stop node1 daemon
+  kvs status                     # Show all running instances
+  kvs status node1               # Show status of node1
+`
+	fmt.Print(help)
+}