🐛 BUG: Inconsistent behavior with pages functions runtime for cache deletion in wrangler pages dev

[yw662]

Which Cloudflare product(s) does this pertain to?

Pages

What version of Wrangler are you using?

2.11.0

What operating system are you using?

macos 13.1

Describe the Bug

In pages functions, wrangler would allow to delete a certain kind of cache entries while the real runtime won't. The code is like

  static async delete(cache: ManagedCache, key: string) {
    try {
      await cache.cache.delete(key)
    } catch (e) {
      logger.log('[cache][workaround]', cache.name, key, String(e))
      await this.put(cache, key, new Response('', { headers: { DELETED: 'DELETED', 'Expires': new Date(0).toUTCString() } }))
    }
  }

Wrangler won't throw on the await cache.delete(key) line, while the actual runtime always throws Error: unable to delete cached response. (and fallback to the workaround, the workaround works though).

The cache entry was added like:

  static async put(cache: ManagedCache, key: string, resp: Response): Promise<void> {
    const headers = new Headers(resp.headers)
    if (!headers.has('Expires') && !headers.has('Cache-Control')) {
      headers.set('Expires', new Date(cache.expires + Date.now()).toUTCString())
    }
    const putted = new Response(resp.clone().body, { headers })
    await cache.cache.put(key, putted)
    return
  }

And inside .wrangler/state/cache, it looks like:

{
  "key": "<key>",
  "expiration": 1677275323,
  "metadata": {
    "status": 200,
    "headers": [
      [
        "access-control-allow-headers",
        "Content-Type, Authorization"
      ],
      [
        "access-control-allow-methods",
        "OPTIONS,POST,GET"
      ],
      [
        "access-control-allow-origin",
        "http://localhost"
      ],
      [
        "connection",
        "keep-alive"
      ],
      [
        "content-length",
        "<length>"
      ],
      [
        "content-type",
        "application/json"
      ],
      [
        "date",
        "Thu, 23 Feb 2023 21:48:43 GMT"
      ],
      [
        "expires",
        "Fri, 24 Feb 2023 21:48:43 GMT"
      ],
      [
        "via",
        "1.1 <YeahThisIsFromAWS>.cloudfront.net (CloudFront)"
      ],
      [
        "x-amz-apigw-id",
        "<hidden>"
      ],
      [
        "x-amz-cf-id",
        "<hidden>"
      ],
      [
        "x-amz-cf-pop",
        "<hidden>"
      ],
      [
        "x-amzn-requestid",
        "<hidden>"
      ],
      [
        "x-amzn-trace-id",
        "<hidden>"
      ],
      [
        "x-cache",
        "Miss from cloudfront"
      ]
    ]
  }
}

(the amazon fields are from upstream, I don't know whether they would be relevant so I would just put them there).

I am not sure whether this is a bug for the real runtime or for workers-sdk. There is a discussion for it at discord id 1074116255134535700 (workers-help > cannot delete cache entries) in cloudflare server.

[mrbbot]

Hey! 👋 Thanks for opening this issue. I've raised it internally. 👍

[mrbbot]

Hey again, it looks like we're not going to be able to fix this for a while. 😞 Does this error occur every time or just occasionally? Apologies about this, I'd keep using your workaround for the time being.

[yw662]

Idk. Should this be considered a bug of miniflare/wrangler or the runtime ?

[mrbbot]

This is a bug in the runtime, or more likely a component the runtime communicates with. 👍

[stenet]

Hey, I get the same error in Cloudflare Pages (production). The error occurs every time cache.delete() is executed. match and put work without any problem.

Is there a workaround for this until the problem is fixed?

[yw662]

Hey, I get the same error in Cloudflare Pages (production). The error occurs every time cache.delete() is executed. match and put work without any problem.

Is there a workaround for this until the problem is fixed?

Yes there is one. Since you can put, you can put sth with a header like DELETED: true (or whatever), and detect that thing when you match.

[stenet]

Thanks! Looks like putting a Response with Cache-Control: max-age=0 works the same like a delete :)

[yw662]

Thanks! Looks like putting a Response with Cache-Control: max-age=0 works the same like a delete :)

Oh yeah I have that in my workaround. So glad to know it can work on its own without other tricks. Thanks.