清漆配置仅缓存未登录的用户

Question

我有一个以 varnish+nginx 为前端的 Ruby on Rails 应用程序。由于除非您是登录用户，否则大多数站点内容都是静态的，因此我想在用户注销时使用清漆大量缓存站点，但仅在用户登录时缓存静态资产。

当用户登录时，他们的 Cookie: 标头中会出现 cookie 'user_credentials'，此外我需要跳过缓存 /login 和 /sessions 以便用户可以首先获得他们的 'user_credentials' cookie .

默认情况下，Rails 不会设置缓存友好的 Cache-control 标头，但是当用户未登录时，我的应用程序会设置一个“public,s-max-age=60”标头。Nginx 设置为返回“远未来”过期标头对于所有静态资产。

我目前的配置在登录时完全绕过缓存，包括静态资产 - 并在注销时为所有内容返回缓存 MISS。我花了几个小时绕圈子，这是我目前的 default.vcl

    director rails_director round-robin {
  { 
    .backend = { 
      .host = "xxx.xxx.xxx.xxx"; 
      .port = "http";
      .probe = {
        .url = "/lbcheck/lbuptest";
        .timeout = 0.3 s;
        .window = 8;
        .threshold = 3;
      }
    } 
  }
}

sub vcl_recv {

  if (req.url ~ "^/login") {
    pipe;
  }

  if (req.url ~ "^/sessions") {
    pipe;
  }
  # The regex used here matches the standard rails cache buster urls
  # e.g. /images/an-image.png?1234567
  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset req.http.cookie;
    lookup;
  } else {
    if (req.http.cookie ~ "user_credentials") {
      pipe;
    }
  }

  # Only cache GET and HEAD requests
  if (req.request != "GET" && req.request != "HEAD") {
    pipe;
  }

}

sub vcl_fetch {

  if (req.url ~ "^/login") {
    pass;
  }

  if (req.url ~ "^/sessions") {
    pass;
  }

  if (req.http.cookie ~ "user_credentials") {
    pass;
  } else {
    unset req.http.Set-Cookie;
  }

  # cache CSS and JS files
  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset req.http.Set-Cookie;
  } 

  if (obj.status >=400 && obj.status <500) {
    error 404 "File not found";
  }

  if (obj.status >=500 && obj.status <600) {
    error 503 "File is Temporarily Unavailable";
  }

}

sub vcl_deliver {
  if (obj.hits > 0) {
          set resp.http.X-Cache = "HIT";
  } else {
          set resp.http.X-Cache = "MISS";
  }
}

Answer 1

好的，最后我设法使用以下 vcl 文件解决了这个问题。请注意，我添加了一些额外的位，以在后端死亡时允许缓存过期宽限期。

似乎我的主要失败是unset req.http.Set-Cookie;在我应该unset obj.http.Set-Cookie;在该vcl_fetch部分使用时使用。（obj在 vcl_fetch 和reqvcl_recv 部分）。

director rails_director round-robin {
  { 
    .backend = { 
      .host = "xxx.xxx.xxx.xxx"; 
      .port = "http";
      .probe = {
        .url = "/lbcheck/lbuptest";
        .timeout = 0.3 s;
        .window = 8;
        .threshold = 3;
      }
    } 
  }
}

sub vcl_recv {

  if (req.backend.healthy) {
    set req.grace = 30s;
  } else {
    set req.grace = 1h;
  }

  if (req.url ~ "^/login") {
    pipe;
  }

  if (req.url ~ "^/sessions") {
    pipe;
  }

  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset req.http.cookie;
    lookup;
  } else {
    if (req.http.cookie ~ "user_credentials") {
      pipe;
    } else {
      unset req.http.cookie;
    }
  }

  # Only cache GET and HEAD requests
  if (req.request != "GET" && req.request != "HEAD") {
    pipe;
  }

}

sub vcl_fetch {

  set obj.grace = 1h;

  if (req.url ~ "^/login") {
    pass;
  }

  if (req.url ~ "^/sessions") {
    pass;
  }

  if (req.http.cookie ~ "user_credentials") {
    pass;
  } else {
    unset obj.http.Set-Cookie;
  }

  # cache CSS and JS files
  if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
    unset obj.http.Set-Cookie;
  } 

  if (obj.status >=400 && obj.status <500) {
    error 404 "File not found";
  }

  if (obj.status >=500 && obj.status <600) {
    error 503 "File is Temporarily Unavailable";
  }

}

sub vcl_deliver {
  if (obj.hits > 0) {
          set resp.http.X-Cache = "HIT";
  } else {
          set resp.http.X-Cache = "MISS";
  }
}