basic sqlite3 connection, reading and parsing client rows, determining next client ID and IP.

.gitignore

@@ -25,3 +25,8 @@ go.work.sum
 # env file
 .env
 
+# binaries
+go_easy
+
+#SQLite databases
+*.db

go.mod

@@ -0,0 +1,5 @@
+module go_easy
+
+go 1.25.3
+
+require github.com/mattn/go-sqlite3 v1.14.32

go.sum

@@ -0,0 +1,2 @@
+github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
+github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=

main.go

@@ -0,0 +1,197 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"time"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type WgEasyClient struct {
+	ID                  int      `json:"id"`
+	UserID              int      `json:"user_id"`
+	InterfaceID         string   `json:"interface_id"`
+	Name                string   `json:"name"`
+	IPv4Address         string   `json:"ipv4_address"`
+	IPv6Address         string   `json:"ipv6_address"`
+	PreUp               string   `json:"pre_up"`
+	PostUp              string   `json:"post_up"`
+	PreDown             string   `json:"pre_down"`
+	PostDown            string   `json:"post_down"`
+	PrivateKey          string   `json:"private_key"`
+	PublicKey           string   `json:"public_key"`
+	PreSharedKey        string   `json:"pre_shared_key"`
+	ExpiresAt           string   `json:"expires_at,omitempty"`
+	AllowedIps          []string `json:"allowed_ips,omitempty"`
+	ServerAllowedIps    []string `json:"server_allowed_ips"`
+	PersistentKeepalive int      `json:"persistent_keepalive"`
+	MTU                 int      `json:"mtu"`
+	JC                  int      `json:"j_c"`
+	JMin                int      `json:"j_min"`
+	JMax                int      `json:"j_max"`
+	I1                  string   `json:"i1,omitempty"`
+	I2                  string   `json:"i2,omitempty"`
+	I3                  string   `json:"i3,omitempty"`
+	I4                  string   `json:"i4,omitempty"`
+	I5                  string   `json:"i5,omitempty"`
+	DNS                 []string `json:"dns,omitempty"`
+	ServerEndpoint      string   `json:"server_endpoint"`
+	Enabled             bool     `json:"enabled"`
+	CreatedAt           string   `json:"created_at"`
+	UpdatedAt           string   `json:"updated_at"`
+}
+
+type WgEasyConfig struct {
+	ID                int       `json:"id"`
+	SetupStep         int       `json:"setup_step"`
+	SessionPassword   string    `json:"session_password"`
+	SessionTimeout    int       `json:"session_timeout"`
+	MetricsPrometheus int       `json:"metrics_prometheus"`
+	MetricsJSON       int       `json:"metrics_json"`
+	MetricsPassword   *string   `json:"metrics_password,omitempty"` // Pointer to handle NULL values
+	CreatedAt         time.Time `json:"created_at"`
+	UpdatedAt         time.Time `json:"updated_at"`
+}
+
+type WgEasyInterfaceConfig struct {
+	Name       string    `json:"name"`
+	Device     string    `json:"device"`
+	Port       int       `json:"port"`
+	PrivateKey string    `json:"private_key"`
+	PublicKey  string    `json:"public_key"`
+	IPv4CIDR   string    `json:"ipv4_cidr"`
+	IPv6CIDR   string    `json:"ipv6_cidr"`
+	MTU        int       `json:"mtu"`
+	Enabled    int       `json:"enabled"`
+	CreatedAt  time.Time `json:"created_at"`
+	UpdatedAt  time.Time `json:"updated_at"`
+}
+
+// getEnv gets an environment variable or returns a default value.
+func getEnv(key, fallback string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
+	}
+	return fallback
+}
+
+func insertNewUser(client WgEasyClient) {
+	db_file := getEnv("DB_FILE", "wg-easy.db")
+	db, err := sql.Open("sqlite3", db_file)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	insertStmt := `INSERT INTO clients_table (userId, interfaceId, name, ipv4Address, ipv6Address, preUp, postUp, preDown, postDown, privateKey, publicKey, preSharedKey, expiresAt, allowedIps, serverAllowedIps, persistentKeepalive, mtu, jC, jMin, jMax, i1, i2, i3, i4, i5, dns, serverEndpoint, enabled) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
+
+	_, err = db.Exec(insertStmt,
+		// Replace these values with the actual data you want to insert
+		client.UserID,
+		client.InterfaceID,
+		client.Name,
+		client.IPv4Address,
+		client.IPv6Address,
+		client.PreUp,
+		client.PostUp,
+		client.PreDown,
+		client.PostDown,
+		client.PrivateKey,
+		client.PublicKey,
+		client.PreSharedKey,
+		client.ExpiresAt,
+		client.AllowedIps,
+		client.ServerAllowedIps,
+		client.PersistentKeepalive,
+		client.MTU,
+		client.JC,
+		client.JMin,
+		client.JMax,
+		client.I1,
+		client.I2,
+		client.I3,
+		client.I4,
+		client.I5,
+		client.DNS,
+		client.ServerEndpoint,
+		client.Enabled,
+		client.CreatedAt,
+		client.UpdatedAt,
+	)
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Println("Inserted new row successfully")
+}
+
+func getLatestClient(rowName string) WgEasyClient {
+	var client WgEasyClient
+	db_file := getEnv("DB_FILE", "wg-easy.db")
+	db, err := sql.Open("sqlite3", db_file)
+	if err != nil {
+		fmt.Println(err)
+	}
+
+	queryString := "SELECT MAX(id), ipv4_address FROM clients_table"
+
+	rows, err := db.Query(queryString, rowName, rowName)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		err = rows.Scan(&client.ID, &client.IPv4Address)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+
+	if err := rows.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return client
+
+}
+
+func getNextIp(ip net.IP) net.IP {
+	ip = ip.To4()
+	if ip == nil {
+		log.Fatal("non ipv4 address")
+	}
+
+	ip[3]++
+
+	return net.IP(ip)
+}
+
+func main() {
+	db_file := getEnv("DB_FILE", "wg-easy.db")
+	db, err := sql.Open("sqlite3", db_file)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	defer db.Close()
+	fmt.Println("Connected to the SQLite database successfully.")
+
+	latestClient := getLatestClient("user_id")
+
+	fmt.Printf("Next Client ID: %d\n", latestClient.ID)
+	lastIp := net.ParseIP(latestClient.IPv4Address)
+
+	if lastIp == nil {
+		fmt.Println("Invalid IP address")
+	} else {
+		fmt.Printf("Next Valid IP: %v\n", getNextIp(lastIp))
+	}
+
+}