Symfony 6.4多LDAP服务配置报错：服务未找到求助

问题重现 #

配置主备两个LDAP服务后，登录时抛出错误：

Cannot check credentials using the "Symfony\Component\Ldap\Ldap" ldap service, as such service is not found. Did you maybe forget to add the "ldap" service tag to this service?

单个LDAP服务配置可正常工作，且通过php bin/console debug:container | grep ldap能确认自定义LDAP服务已存在。

错误原因 #

1. Firewall配置错误：form_login_ldap中的service参数填了类名Symfony\Component\Ldap\Ldap，但存在多个LDAP实例时，Symfony无法通过类名定位到具体服务，必须指定自定义的服务ID（如main_ldap）。
2. Services配置笔误：main_ldap服务的参数引用了不存在的@ldap_adapter，实际应该是你定义的@main_ldap_adapter。

修复步骤 #

1. 修正Firewall的LDAP服务引用 #

修改security.yaml中login防火墙的form_login_ldap配置，将service值改为你的主LDAP服务ID：

security:
    ...
    firewalls:
        login:
          pattern: ^/api/login
          provider: ldap_main_provider
          form_login_ldap:
            login_path: api_login
            check_path: api_login
            username_parameter: login
            password_parameter: password
            service: main_ldap # 替换为自定义的主LDAP服务ID
            dn_string: '%env(LDAP_DN_STRING)%'
            success_handler: App\Security\Authentication\AuthenticationSuccessHandler
            failure_handler: App\Security\Authentication\AuthenticationFailureHandler
    ...

2. 修复Services中的适配器引用错误 #

修改services.yaml里的main_ldap服务参数，把错误的@ldap_adapter改成@main_ldap_adapter：

services:
    ...     
    main_ldap:
      class: Symfony\Component\Ldap\Ldap
      arguments: ['@main_ldap_adapter'] # 修正为正确的适配器服务ID
      tags: ['ldap']

    backup_ldap:
      class: Symfony\Component\Ldap\Ldap
      arguments: ['@backup_ldap_adapter']
      tags: ['ldap']
    ...

3. 可选：实现主备LDAP自动切换 #

如果需要主LDAP故障时自动切换到备LDAP，可封装一个自定义LDAP服务：

第一步：创建自定义LDAP类

// src/Ldap/FallbackLdap.php
namespace App\Ldap;

use Symfony\Component\Ldap\Exception\ConnectionException;
use Symfony\Component\Ldap\LdapInterface;

class FallbackLdap implements LdapInterface
{
    private LdapInterface $mainLdap;
    private LdapInterface $backupLdap;

    public function __construct(LdapInterface $mainLdap, LdapInterface $backupLdap)
    {
        $this->mainLdap = $mainLdap;
        $this->backupLdap = $backupLdap;
    }

    public function connect(string $host = null, int $port = null): void
    {
        try {
            $this->mainLdap->connect($host, $port);
        } catch (ConnectionException $e) {
            $this->backupLdap->connect($host, $port);
        }
    }

    public function bind(string $dn = null, string $password = null): void
    {
        try {
            $this->mainLdap->bind($dn, $password);
        } catch (ConnectionException $e) {
            $this->backupLdap->bind($dn, $password);
        }
    }

    // 实现LdapInterface的其他方法，统一委托给可用的LDAP实例
    public function query(string $dn, string $query, array $options = []): \Symfony\Component\Ldap\Query\QueryInterface
    {
        try {
            return $this->mainLdap->query($dn, $query, $options);
        } catch (ConnectionException $e) {
            return $this->backupLdap->query($dn, $query, $options);
        }
    }

    public function escape(string $value, string $ignore = '', int $flags = 0): string
    {
        try {
            return $this->mainLdap->escape($value, $ignore, $flags);
        } catch (ConnectionException $e) {
            return $this->backupLdap->escape($value, $ignore, $flags);
        }
    }
}

第二步：注册自定义服务

在services.yaml中添加：

services:
    ...
    App\Ldap\FallbackLdap:
        arguments: ['@main_ldap', '@backup_ldap']
        tags: ['ldap']
    ...

第三步：更新Security配置

使用自定义服务替换原有的LDAP服务：

security:
    ...
    providers:
      ldap_fallback_provider:
        ldap:
          service: App\Ldap\FallbackLdap
          base_dn: '%env(LDAP_BASE_DN)%'
          search_dn: '%env(LDAP_SEARCH_DN)%'
          search_password: '%env(LDAP_SEARCH_PASSWORD)%'
          default_roles: ROLE_USER
          uid_key: uid
    firewalls:
        login:
          provider: ldap_fallback_provider
          form_login_ldap:
            service: App\Ldap\FallbackLdap
            # 其他配置保持不变
    ...

内容的提问来源于stack exchange，提问作者phpdev