feat: production-ready domain control dashboard

internal/config/config.go

@@ -0,0 +1,92 @@
+package config
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	DefaultIPv4Primary  = "https://api.ipify.org"
+	DefaultIPv4Fallback = "https://ifconfig.co/ip"
+	DefaultIPv6Primary  = "https://api6.ipify.org"
+	DefaultIPv6Fallback = "https://ifconfig.co/ip"
+)
+
+type Config struct {
+	Address         string
+	DataDir         string
+	DatabasePath    string
+	MasterKeyFile   string
+	CookieSecure    bool
+	SessionTTL      time.Duration
+	HCloudBaseURL   string
+	Mode            string
+	ShutdownTimeout time.Duration
+}
+
+func Load() (Config, error) {
+	dataDir := value("APP_DATA_DIR", "/data")
+	address := value("APP_ADDRESS", ":8080")
+	if _, _, err := net.SplitHostPort(address); err != nil {
+		return Config{}, fmt.Errorf("APP_ADDRESS must be host:port: %w", err)
+	}
+
+	mode := strings.ToLower(value("APP_MODE", "lan"))
+	if mode != "lan" && mode != "https" {
+		return Config{}, fmt.Errorf("APP_MODE must be either lan or https")
+	}
+
+	ttl, err := duration("APP_SESSION_TTL", 8*time.Hour)
+	if err != nil || ttl < time.Hour || ttl > 7*24*time.Hour {
+		return Config{}, fmt.Errorf("APP_SESSION_TTL must be between 1h and 168h")
+	}
+	shutdownTimeout, err := duration("APP_SHUTDOWN_TIMEOUT", 15*time.Second)
+	if err != nil {
+		return Config{}, fmt.Errorf("APP_SHUTDOWN_TIMEOUT: %w", err)
+	}
+
+	keyFile := os.Getenv("APP_MASTER_KEY_FILE")
+	if keyFile == "" {
+		return Config{}, fmt.Errorf("APP_MASTER_KEY_FILE is required (mount a Docker secret there)")
+	}
+
+	cookieSecure := mode == "https"
+	if raw := os.Getenv("APP_COOKIE_SECURE"); raw != "" {
+		parsed, parseErr := strconv.ParseBool(raw)
+		if parseErr != nil {
+			return Config{}, fmt.Errorf("APP_COOKIE_SECURE: %w", parseErr)
+		}
+		cookieSecure = parsed
+	}
+
+	return Config{
+		Address:         address,
+		DataDir:         dataDir,
+		DatabasePath:    value("APP_DATABASE_PATH", filepath.Join(dataDir, "dyndns.db")),
+		MasterKeyFile:   keyFile,
+		CookieSecure:    cookieSecure,
+		SessionTTL:      ttl,
+		HCloudBaseURL:   strings.TrimRight(value("APP_HCLOUD_BASE_URL", "https://api.hetzner.cloud/v1"), "/"),
+		Mode:            mode,
+		ShutdownTimeout: shutdownTimeout,
+	}, nil
+}
+
+func value(name, fallback string) string {
+	if v := strings.TrimSpace(os.Getenv(name)); v != "" {
+		return v
+	}
+	return fallback
+}
+
+func duration(name string, fallback time.Duration) (time.Duration, error) {
+	if raw := strings.TrimSpace(os.Getenv(name)); raw != "" {
+		return time.ParseDuration(raw)
+	}
+	return fallback, nil
+}