Multiple header_filter_by_lua_block wont working with FastCGI cache

[i.zaporozhets.owox.com@…]

One lua script in server section changes GET parameters of fcgi cached response to current, because i wont include GET in facgi_cache_key (buisines logic).
Including empty second lua script in location causes first lua script does not working.
Here is example:

fastcgi_cache_path /var/www/test.com/cache/nginx/products levels=1:2 keys_zone=fastcgi_cache_foo:512m max_size=320G inactive=12h;

upstream backends  {
      server 127.0.0.1:9000 weight=1 max_fails=2 fail_timeout=5s;
}

server {
	listen  *:80;
	server_name test.com;

	header_filter_by_lua_block {
		 -- Update GET parameters with current get parameters in cached response
                if ngx.resp.get_headers()["Location"] ~= nil and ngx.var.upstream_cache_status ~= nil then

			local is_cache = string.find("HIT STALE UPDATING", ngx.var.upstream_cache_status)

			if is_cache ~= nil then
				local location = string.gsub(ngx.header.location, "(\?.*)", "")

				if ngx.header.cacheparam ~= nil then
			    		location = location .. "?" .. ngx.header.cacheparam
				elseif ngx.var.is_args ~= '' then
			    		location = location .. "?" .. ngx.var.args
				end
				ngx.header.location = location
			end
		end
	}

	root /var/www/test.com/cgi-bin;
        index index.php;

        location / {
		try_files $uri $uri/ /index.php;
	}

	location ~ \.php$ {

		try_files $uri =404;
		fastcgi_pass backends;
		fastcgi_index index.php;
		include fastcgi_params;
		fastcgi_param SCRIPT_FILENAME /var/www/test.com/cgi-bin/index.php;
		fastcgi_param SCRIPT_NAME /var/www/test.com/cgi-bin/index.php;

		fastcgi_cache fastcgi_cache_foo;
		fastcgi_cache_valid 200 304 404 25h;
		fastcgi_cache_valid 302 5m;
		fastcgi_cache_valid 500 502 20s;

		fastcgi_param BACKGROUND_UPDATE_CACHE_ZONE 'fastcgi_cache_products';
		fastcgi_param BACKGROUND_UPDATE_CACHE_STATUSES '302';

		fastcgi_cache_lock on;
		fastcgi_cache_lock_timeout 25s;

		add_header X-Cache-Status $upstream_cache_status;

		set $fastcgi_cache_key "$request_method|$scheme|$host|$uri|old";
                fastcgi_cache_key $fastcgi_cache_key;
                fastcgi_param BACKGROUND_UPDATE_CACHE_KEY $fastcgi_cache_key;

		#If uncomment this, everything is working
		#header_filter_by_lua_block {}

	}

}

PHP script is very simple:

<?php

header("Location: foo?" . http_build_query($_GET));
exit;

Request cached page with commented second block header_filter_by_lua_block:
curl -v ​http://test.com/?test1

• About to connect() to test.com port 80 (#0)
• Trying 127.0.0.1... connected
• Connected to test.com (127.0.0.1) port 80 (#0)

  GET /?test1 HTTP/1.1
  User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
  Host: test.com
  Accept: */*
  

< HTTP/1.1 302 Found
< Server: nginx
< Date: Mon, 04 Jun 2018 15:22:27 GMT
< Content-Type: text/html; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Keep-Alive: timeout=75
< X-Powered-By: PHP/7.1.16
< Location: foo?test1=
< X-Cache-Status: HIT
<

• Connection #0 to host test.com left intact

curl -v ​http://test.com/?test2

• About to connect() to test.com port 80 (#0)
• Trying 127.0.0.1... connected
• Connected to test.com (127.0.0.1) port 80 (#0)

  GET /?test2 HTTP/1.1
  User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
  Host: test.com
  Accept: */*
  

< HTTP/1.1 302 Found
< Server: nginx
< Date: Mon, 04 Jun 2018 15:22:30 GMT
< Content-Type: text/html; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Keep-Alive: timeout=75
< X-Powered-By: PHP/7.1.16
< location: foo?test2
< X-Cache-Status: HIT
<

• Connection #0 to host test.com left intact
• Closing connection #0

Request cached page with uncommented block:

curl -v ​http://test.com/?test1

• About to connect() to test.com port 80 (#0)
• Trying 127.0.0.1... connected
• Connected to test.com (127.0.0.1) port 80 (#0)

  GET /?test1 HTTP/1.1
  User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
  Host: test.com
  Accept: */*
  

< HTTP/1.1 302 Found
< Server: nginx
< Date: Mon, 04 Jun 2018 15:24:24 GMT
< Content-Type: text/html; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Keep-Alive: timeout=75
< X-Powered-By: PHP/7.1.16
< Location: foo?test1=
< X-Cache-Status: HIT
<

• Connection #0 to host test.com left intact
• Closing connection #0

curl -v ​http://test.com/?test2

• About to connect() to test.com port 80 (#0)
• Trying 127.0.0.1... connected
• Connected to test.com (127.0.0.1) port 80 (#0)

  GET /?test2 HTTP/1.1
  User-Agent: curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2
  Host: test.com
  Accept: */*
  

< HTTP/1.1 302 Found
< Server: nginx
< Date: Mon, 04 Jun 2018 15:24:26 GMT
< Content-Type: text/html; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Keep-Alive: timeout=75
< X-Powered-By: PHP/7.1.16
< Location: foo?test1=
< X-Cache-Status: HIT
<

• Connection #0 to host test.com left intact
• Closing connection #0

[Maxim Dounin]

For problems with 3rd party modules please contact module authors instead.

Note though that in this particular case the behaviour looks perfectly correct as per normal nginx inheritance rules: a directive is inherited from the previous levels if the directive is not used on the current level. Using header_filter_by_lua_block in the location ~ \.php$ block prevents inheritance of the header_filter_by_lua_block defined at the server{} level to the location in question. Instead, the one defined in the location ~ \.php$ block will be used.