Symfony 6.2升级至6.3后Varnish缓存出现503首字节超时问题

将Symfony应用从6.2版本升级至6.3版本后，本地运行一切正常，但在预发布（staging）环境出现异常：通过API登录或获取部分资源时，收到Varnish缓存服务器返回的503 First Byte Timeout错误。不过查看Kubernetes日志显示，应用自身返回的响应状态码为204，头部信息也正常。

为消除升级后的弃用提示，我修改了部分Normalizer类，以UserNormalizer为例：

升级前版本 #

<?php

declare(strict_types=1);

namespace App\Api\User\Serializer;

use App\Entity\User;
use App\Repository\CategoryRepository;
use Symfony\Component\Serializer\Normalizer\CacheableSupportsMethodInterface;
use Symfony\Component\Serializer\Normalizer\NormalizerInterface;

class UserNormalizer implements NormalizerInterface, CacheableSupportsMethodInterface
{
    public function __construct(
        private readonly NormalizerInterface $itemNormalizer,
        private readonly CategoryRepository $categoryRepository,
    ) {
    }

    /** @param User $object */
    public function normalize($object, $format = null, array $context = []): array|string
    {
        $object->categoryIds = $this->categoryRepository->findIdsWithJobsByUser($object);

        return $this->itemNormalizer->normalize($object, $format, $context);
    }

    public function supportsNormalization($data, $format = null, array $context = []): bool
    {
        return $data instanceof User;
    }

    public function hasCacheableSupportsMethod(): bool
    {
        return true;
    }
}

升级后版本 #

<?php

declare(strict_types=1);

namespace App\Api\User\Serializer;

use App\Entity\User;
use App\Repository\CategoryRepository;
use Symfony\Component\Serializer\Normalizer\NormalizerInterface;

final readonly class UserNormalizer implements NormalizerInterface
{
    public function __construct(
        private NormalizerInterface $itemNormalizer,
        private CategoryRepository $categoryRepository,
    ) {
    }

    /** @param User $object */
    public function normalize($object, $format = null, array $context = []): array|string
    {
        $object->categoryIds = $this->categoryRepository->findIdsWithJobsByUser($object);

        return $this->itemNormalizer->normalize($object, $format, $context);
    }

    public function supportsNormalization($data, $format = null, array $context = []): bool
    {
        return $data instanceof User;
    }

    public function getSupportedTypes(?string $format): array
    {
        return [
            '*' => false,
            User::class => true,
        ];
    }
}

我是按照Symfony官方文档及内置Normalizer示例进行修改的：移除了CacheableSupportsMethodInterface（及对应的hasCacheableSupportsMethod()方法），替换为getSupportedTypes()方法。

应用运行在Google Kubernetes Engine（GCP），通过Fastly交付。补充：部分资源（如静态页面，同样使用缓存且有类似getSupportedTypes()实现）可正常访问。

有没有人遇到过类似问题？

内容的提问来源于stack exchange，提问作者ppoz21