rework new mechanism with the script

.gitignore

@@ -1,3 +1,4 @@
 dhcp-clients-webapp-backend/bin/
+dhcp-clients-webapp-backend/tmp/
 .docker-image
-
+test-db.sqlite3

dhcp-clients-webapp-backend/pkg/trackerdb/trackerdb.go

@@ -11,17 +11,6 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
-// DhcpClient represents the structure for a DHCP client.
-// The DHCP client might be currently connected to the server or not; in other words this
-// may represent a DHCP client that has been connected in the past, but currently is not.
-type DhcpClient struct {
-	MacAddr      net.HardwareAddr `json:"mac_addr"`
-	Hostname     string           `json:"hostname"`
-	HasStaticIP  bool             `json:"has_static_ip"`
-	FriendlyName string           `json:"friendly_name"`
-	LastSeen     time.Time        `json:"last_seen"`
-}
-
 // DhcpClientTrackerDB manages the database operations for DHCP clients.
 type DhcpClientTrackerDB struct {
 	DB *sql.DB
@@ -34,20 +23,7 @@ func NewDhcpClientTrackerDB(dbPath string) (*DhcpClientTrackerDB, error) {
 		return nil, err
 	}
 
-	// Create table if not exists
-	createTableQuery := `
-	CREATE TABLE IF NOT EXISTS dhcp_clients (
-		mac_addr TEXT PRIMARY KEY,
-		hostname TEXT,
-		has_static_ip INTEGER,
-		friendly_name TEXT,
-		last_seen TEXT
-	);
-	`
-	_, err = db.Exec(createTableQuery)
-	if err != nil {
-		return nil, err
-	}
+	// the table should be already there as it's created by the dnsmasq helper script
 
 	return &DhcpClientTrackerDB{DB: db}, nil
 }
@@ -59,6 +35,21 @@ func NewTestDB() DhcpClientTrackerDB {
 	if err != nil {
 		log.Fatal("Failed to initialize test database")
 	}
+
+	// Create table
+	createTableQuery := `
+	CREATE TABLE IF NOT EXISTS dhcp_clients (
+		mac_addr TEXT PRIMARY KEY,
+		hostname TEXT,
+		last_seen TEXT,
+		dhcp_server_start_counter INT
+	);
+	`
+	_, err = db.DB.Exec(createTableQuery)
+	if err != nil {
+		log.Fatal("Failed to initialize test database")
+	}
+
 	return *db
 }
 
@@ -79,16 +70,15 @@ func NewTestDBWithData(clientsInDB []DhcpClient) DhcpClientTrackerDB {
 // TrackNewDhcpClient inserts a new DHCP client into the database.
 func (d *DhcpClientTrackerDB) TrackNewDhcpClient(client DhcpClient) error {
 	insertQuery := `
-	INSERT INTO dhcp_clients (mac_addr, hostname, has_static_ip, friendly_name, last_seen)
-	VALUES (?, ?, ?, ?, ?)
+	INSERT INTO dhcp_clients (mac_addr, hostname, last_seen, dhcp_server_start_counter)
+	VALUES (?, ?, ?, ?)
 	ON CONFLICT(mac_addr) DO UPDATE SET 
 		hostname=excluded.hostname, 
-		has_static_ip=excluded.has_static_ip,
-		friendly_name=excluded.friendly_name,
-		last_seen=excluded.last_seen;
+		last_seen=excluded.last_seen,
+		dhcp_server_start_counter=excluded.dhcp_server_start_counter;
 	`
 
-	_, err := d.DB.Exec(insertQuery, client.MacAddr.String(), client.Hostname, client.HasStaticIP, client.FriendlyName, client.LastSeen.Format(time.RFC3339))
+	_, err := d.DB.Exec(insertQuery, client.MacAddr.String(), client.Hostname, client.LastSeen.Format(time.RFC3339), 0)
 	if err != nil {
 		return err
 	}
@@ -98,14 +88,14 @@ func (d *DhcpClientTrackerDB) TrackNewDhcpClient(client DhcpClient) error {
 
 // GetDhcpClient retrieves a DHCP client by its MAC address.
 func (d *DhcpClientTrackerDB) GetDhcpClient(macAddr net.HardwareAddr) (*DhcpClient, error) {
-	query := `SELECT mac_addr, hostname, has_static_ip, friendly_name, last_seen FROM dhcp_clients WHERE mac_addr = ?`
+	query := `SELECT mac_addr, hostname, last_seen FROM dhcp_clients WHERE mac_addr = ?`
 	row := d.DB.QueryRow(query, macAddr.String())
 
 	var client DhcpClient
 	var lastSeen string
 	var mac string
 
-	err := row.Scan(&mac, &client.Hostname, &client.HasStaticIP, &client.FriendlyName, &lastSeen)
+	err := row.Scan(&mac, &client.Hostname, &lastSeen)
 	if err != nil {
 		if err == sql.ErrNoRows {
 			return nil, fmt.Errorf("client with mac_addr %s not found", macAddr)
@@ -159,7 +149,7 @@ func (d *DhcpClientTrackerDB) UnmarshalDhcpClient(data string) error {
 // which identifies the currently-alive DHCP clients.
 func (d *DhcpClientTrackerDB) GetDeadDhcpClients(aliveClients []net.HardwareAddr) ([]DhcpClient, error) {
 	// Step 1: Get all DHCP clients from the database
-	rows, err := d.DB.Query("SELECT mac_addr, hostname, has_static_ip, friendly_name, last_seen FROM dhcp_clients")
+	rows, err := d.DB.Query("SELECT mac_addr, hostname, last_seen FROM dhcp_clients")
 	if err != nil {
 		return nil, fmt.Errorf("failed to query dhcp_clients: %v", err)
 	}
@@ -179,7 +169,7 @@ func (d *DhcpClientTrackerDB) GetDeadDhcpClients(aliveClients []net.HardwareAddr
 		var mac string
 
 		// Scan the row data into the DhcpClient struct
-		err := rows.Scan(&mac, &client.Hostname, &client.HasStaticIP, &client.FriendlyName, &lastSeenStr)
+		err := rows.Scan(&mac, &client.Hostname, &lastSeenStr)
 		if err != nil {
 			return nil, fmt.Errorf("failed to scan row: %v", err)
 		}

dhcp-clients-webapp-backend/pkg/trackerdb/trackerdb_test.go

@@ -52,11 +52,11 @@ func CompareDhcpClientSlices(slice1, slice2 []DhcpClient) bool {
 // TestAddDhcpClient tests the AddDhcpClient method.
 func TestAddDhcpClient(t *testing.T) {
 	client := DhcpClient{
-		MacAddr:      MustParseMAC("AA:BB:CC:DD:EE:FF"),
-		Hostname:     "test-host",
-		HasStaticIP:  true,
-		FriendlyName: "Test Client",
-		LastSeen:     time.Now(),
+		MacAddr:  MustParseMAC("AA:BB:CC:DD:EE:FF"),
+		Hostname: "test-host",
+		//HasStaticIP:  true,
+		//FriendlyName: "Test Client",
+		LastSeen: time.Now(),
 	}
 
 	db := NewTestDBWithData([]DhcpClient{client})
@@ -68,8 +68,8 @@ func TestAddDhcpClient(t *testing.T) {
 	// Compare the inserted and retrieved client using assertions
 	assert.Equal(t, client.MacAddr, retrievedClient.MacAddr, "MacAddr mismatch")
 	assert.Equal(t, client.Hostname, retrievedClient.Hostname, "Hostname mismatch")
-	assert.Equal(t, client.HasStaticIP, retrievedClient.HasStaticIP, "HasStaticIP mismatch")
-	assert.Equal(t, client.FriendlyName, retrievedClient.FriendlyName, "FriendlyName mismatch")
+	//assert.Equal(t, client.HasStaticIP, retrievedClient.HasStaticIP, "HasStaticIP mismatch")
+	//assert.Equal(t, client.FriendlyName, retrievedClient.FriendlyName, "FriendlyName mismatch")
 
 	// Allow for slight differences in time, but the retrieved and original times should be very close
 	assert.WithinDuration(t, client.LastSeen, retrievedClient.LastSeen, time.Second, "LastSeen timestamp mismatch")
@@ -78,11 +78,11 @@ func TestAddDhcpClient(t *testing.T) {
 // TestGetDhcpClient tests the GetDhcpClient method.
 func TestGetDhcpClient(t *testing.T) {
 	client := DhcpClient{
-		MacAddr:      MustParseMAC("AA:BB:CC:DD:EE:FF"),
-		Hostname:     "test-host",
-		HasStaticIP:  true,
-		FriendlyName: "Test Client",
-		LastSeen:     time.Now(),
+		MacAddr:  MustParseMAC("AA:BB:CC:DD:EE:FF"),
+		Hostname: "test-host",
+		//HasStaticIP:  true,
+		//FriendlyName: "Test Client",
+		LastSeen: time.Now(),
 	}
 
 	db := NewTestDBWithData([]DhcpClient{client})
@@ -94,8 +94,8 @@ func TestGetDhcpClient(t *testing.T) {
 	// Check the values of the retrieved client using assertions
 	assert.Equal(t, client.MacAddr, retrievedClient.MacAddr, "MacAddr mismatch")
 	assert.Equal(t, client.Hostname, retrievedClient.Hostname, "Hostname mismatch")
-	assert.Equal(t, client.HasStaticIP, retrievedClient.HasStaticIP, "HasStaticIP mismatch")
-	assert.Equal(t, client.FriendlyName, retrievedClient.FriendlyName, "FriendlyName mismatch")
+	//assert.Equal(t, client.HasStaticIP, retrievedClient.HasStaticIP, "HasStaticIP mismatch")
+	//assert.Equal(t, client.FriendlyName, retrievedClient.FriendlyName, "FriendlyName mismatch")
 	assert.WithinDuration(t, client.LastSeen, retrievedClient.LastSeen, time.Second, "LastSeen timestamp mismatch")
 
 	// Test retrieving a non-existent client
@@ -110,25 +110,25 @@ func TestGetDeadDhcpClients(t *testing.T) {
 	// Create some test DHCP clients in the database
 	clientsInDB := []DhcpClient{
 		{
-			MacAddr:      MustParseMAC("AA:BB:CC:DD:EE:FF"),
-			Hostname:     "test-host-1",
-			HasStaticIP:  true,
-			FriendlyName: "Test Client 1",
-			LastSeen:     timeNow,
+			MacAddr:  MustParseMAC("AA:BB:CC:DD:EE:FF"),
+			Hostname: "test-host-1",
+			//HasStaticIP:  true,
+			//FriendlyName: "Test Client 1",
+			LastSeen: timeNow,
 		},
 		{
-			MacAddr:      MustParseMAC("11:22:33:44:55:66"),
-			Hostname:     "test-host-2",
-			HasStaticIP:  false,
-			FriendlyName: "Test Client 2",
-			LastSeen:     timeNow,
+			MacAddr:  MustParseMAC("11:22:33:44:55:66"),
+			Hostname: "test-host-2",
+			//HasStaticIP:  false,
+			//FriendlyName: "Test Client 2",
+			LastSeen: timeNow,
 		},
 		{
-			MacAddr:      MustParseMAC("77:88:99:AA:BB:CC"),
-			Hostname:     "test-host-3",
-			HasStaticIP:  true,
-			FriendlyName: "Test Client 3",
-			LastSeen:     timeNow,
+			MacAddr:  MustParseMAC("77:88:99:AA:BB:CC"),
+			Hostname: "test-host-3",
+			//HasStaticIP:  true,
+			//FriendlyName: "Test Client 3",
+			LastSeen: timeNow,
 		},
 	}
 

dhcp-clients-webapp-backend/pkg/trackerdb/types.go

@@ -0,0 +1,38 @@
+package trackerdb
+
+import (
+	"encoding/json"
+	"net"
+	"time"
+
+	// import sqlite3 driver, so that database/sql package will know how to deal with "sqlite3" type
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// DhcpClient represents the structure for a DHCP client.
+// The DHCP client might be currently connected to the server or not; in other words this
+// may represent a DHCP client that has been connected in the past, but currently is not.
+type DhcpClient struct {
+	MacAddr      net.HardwareAddr
+	Hostname     string
+	HasStaticIP  bool
+	FriendlyName string
+	LastSeen     time.Time
+}
+
+// MarshalJSON customizes the JSON serialization for DhcpClientData
+func (d DhcpClient) MarshalJSON() ([]byte, error) {
+	return json.Marshal(&struct {
+		MacAddr      string `json:"mac_addr"`
+		Hostname     string `json:"hostname"`
+		HasStaticIP  bool   `json:"has_static_ip"`
+		FriendlyName string `json:"friendly_name"`
+		LastSeen     int64  `json:"last_seen"`
+	}{
+		MacAddr:      d.MacAddr.String(),
+		Hostname:     d.Hostname,
+		HasStaticIP:  d.HasStaticIP,
+		FriendlyName: d.FriendlyName,
+		LastSeen:     d.LastSeen.Unix(),
+	})
+}

dhcp-clients-webapp-backend/pkg/uibackend/types.go

@@ -97,7 +97,9 @@ type AddonConfig struct {
 	WebUIPort int `json:"web_ui_port"`
 }
 
-// WebSocket
+// WebSocketMessage defines which contents get transmitted over the websocket in the
+// BACKEND -> UI direction.
+// Any structure contained here should have a sensible JSON marshalling helper.
 type WebSocketMessage struct {
 	// CurrentClients contains the list of clients currently "connected" to the dnsmasq server.
 	// In this context "connected" means: that sent DHCP traffic since the dnsmasq server was started.
@@ -106,4 +108,8 @@ type WebSocketMessage struct {
 	// PastClients contains the list of clients that were connected in the past, but never
 	// obtained a DHCP lease since the last dnsmasq server restart.
 	PastClients []trackerdb.DhcpClient `json:"past_clients"`
+
+	// DHCPServerStartTime indicates the point in time where
+	// the dnsmasq server was last started, expressed as Unix epoch.
+	DHCPServerStartTime int64 `json:"dhcp_server_starttime"`
 }

dhcp-clients-webapp-backend/pkg/uibackend/uibackend.go

@@ -40,17 +40,19 @@ type UIBackend struct {
 	dhcpStartIP net.IP
 	dhcpEndIP   net.IP
 
+	// time this application was started
+	startTimestamp time.Time
+
 	// the actual HTTP server
 	serverPort int
 	server     http.Server
 	upgrader   websocket.Upgrader
 
 	// more HTTP server resources
-	// the CSS template as read from file
 	isTestingMode bool
-	htmlTemplate  *template.Template
-	jsContents    string
-	cssContents   string
+	htmlTemplate  *template.Template // read from disk at startup
+	jsContents    string             // read from disk at startup
+	cssContents   string             // read from disk at startup
 
 	// map of connected websockets
 	clients     map[*websocket.Conn]bool
@@ -60,7 +62,7 @@ type UIBackend struct {
 	dhcpClientData     []DhcpClientData
 	dhcpClientDataLock sync.Mutex
 
-	// DB tracking all DHCP clients
+	// DB tracking all DHCP clients, used to provide the "past DHCP clients" feature
 	trackerDB trackerdb.DhcpClientTrackerDB
 
 	// channel used to broadcast tabular data from backend->frontend
@@ -82,6 +84,7 @@ func NewUIBackend() UIBackend {
 	isTestingMode := os.Getenv("LOCAL_TESTING") != ""
 
 	return UIBackend{
+		startTimestamp:        time.Now(),
 		ipAddressReservations: make(map[netip.Addr]IpAddressReservation),
 		friendlyNames:         make(map[string]DhcpClientFriendlyName),
 		clients:               make(map[*websocket.Conn]bool),
@@ -148,10 +151,14 @@ func (b *UIBackend) getWebSocketMessage() WebSocketMessage {
 		log.Default().Printf("ERR: failed to get list of dead/past DHCP clients: %s", err.Error())
 		// keep going
 	}
-
 	return WebSocketMessage{
 		CurrentClients: currentClients,
 		PastClients:    deadClients,
+
+		// we approximate the DHCP server start time with this app's start time;
+		// the reason is that inside the HA addon, dnsmasq is started at about the same
+		// time of this app
+		DHCPServerStartTime: b.startTimestamp.Unix(),
 	}
 }