more fix and update

apps/ldap-auth/dns.go

@@ -0,0 +1,131 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os"
+	"strings"
+	"time"
+)
+
+var (
+	ldapDNSServers    []string
+	ldapStaticHosts   map[string]string
+	ldapNetworkingSet bool
+)
+
+func initLDAPNetworking() {
+	if ldapNetworkingSet {
+		return
+	}
+	ldapDNSServers = parseCSV(os.Getenv("LDAP_DNS_SERVERS"))
+	ldapStaticHosts = parseStaticHostMap(os.Getenv("LDAP_EXTRA_HOSTS"))
+	ldapNetworkingSet = true
+}
+
+func parseCSV(raw string) []string {
+	parts := strings.Split(raw, ",")
+	result := make([]string, 0, len(parts))
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part != "" {
+			result = append(result, part)
+		}
+	}
+	return result
+}
+
+func parseStaticHostMap(raw string) map[string]string {
+	result := make(map[string]string)
+	for _, part := range parseCSV(raw) {
+		host, ip, ok := strings.Cut(part, ":")
+		if !ok {
+			continue
+		}
+		host = strings.TrimSpace(host)
+		ip = strings.TrimSpace(ip)
+		if host == "" || ip == "" {
+			continue
+		}
+		result[strings.ToLower(host)] = ip
+	}
+	return result
+}
+
+func resolveHostAddress(host string) (string, error) {
+	initLDAPNetworking()
+
+	host = strings.TrimSpace(host)
+	if host == "" {
+		return "", fmt.Errorf("пустой LDAP host")
+	}
+	if net.ParseIP(host) != nil {
+		return host, nil
+	}
+
+	lowerHost := strings.ToLower(host)
+	if ip, ok := ldapStaticHosts[lowerHost]; ok {
+		return ip, nil
+	}
+
+	if len(ldapDNSServers) > 0 {
+		if ip, err := lookupViaCustomDNS(host, ldapDNSServers); err == nil {
+			return ip, nil
+		} else if len(ldapStaticHosts) == 0 {
+			return "", err
+		}
+	}
+
+	addrs, err := net.LookupHost(host)
+	if err != nil {
+		return "", err
+	}
+	if ip := firstIPv4(addrs); ip != "" {
+		return ip, nil
+	}
+	if len(addrs) > 0 {
+		return addrs[0], nil
+	}
+	return "", fmt.Errorf("не найден IP-адрес для %s", host)
+}
+
+func lookupViaCustomDNS(host string, servers []string) (string, error) {
+	var lastErr error
+	for _, server := range servers {
+		resolver := &net.Resolver{
+			PreferGo: true,
+			Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+				dialer := net.Dialer{Timeout: 4 * time.Second}
+				return dialer.DialContext(ctx, "udp", net.JoinHostPort(server, "53"))
+			},
+		}
+
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		addrs, err := resolver.LookupHost(ctx, host)
+		cancel()
+		if err != nil {
+			lastErr = err
+			continue
+		}
+		if ip := firstIPv4(addrs); ip != "" {
+			return ip, nil
+		}
+		if len(addrs) > 0 {
+			return addrs[0], nil
+		}
+	}
+	if lastErr != nil {
+		return "", lastErr
+	}
+	return "", fmt.Errorf("DNS-серверы не вернули адрес для %s", host)
+}
+
+func firstIPv4(addrs []string) string {
+	for _, addr := range addrs {
+		if strings.Contains(addr, ".") {
+			return addr
+		}
+	}
+	return ""
+}