Proxy_cache partial response?

Server NGINX
1

will nginx cache partial response when upstream prematutely close
connection?

In our production environment, we found the following scenario requires
one
to manually clear proxy cache:

  1. nginx asks upstrean for some large file, e.g., 5000KB

  2. upstream send response, it flushes response header which (at least)
    contains content-length

  3. Network is completely broken when 200KB was received by nginx. In
    about
    the same time, upstream closed connection by sending a FIN

  4. nginx cache the partial response and use it to serve subsequent
    requests
    until expiration.

  5. Browser request this large file then indefinitely hangs because
    content-length indicates there were more to come but actually nginx has
    nothing to send.

lei yang

2

Hi,

will nginx cache partial response when upstream prematutely close
connection?

Sadly, yes.

Best regards,
Piotr S. < [email protected] >

3

Hi, my colleague found this interesting comment in nginx’s source code:

        if (p->upstream_done) {
            ngx_http_file_cache_update(r, u->pipe->temp_file);

        } else if (p->upstream_eof) {

  •           /* TODO: check length & update cache */*

         ngx_http_file_cache_update(r, u->pipe->temp_file);

     } else if (p->upstream_error) {
         ngx_http_file_cache_free(r->cache, u->pipe->temp_file);
     }

next time shall I ask a question, I’d better to do this first: *grep -ri
'TODO: ’ **