srcache_store won't add items

yann.coleu · 2014-07-04T22:40:27+00:00

Thanks agentzh for quick reply.Official documentation around how to use "ngx.re.match" was helpful. When used correctly one can print the error string in Lua...

srcache_store won't add items

yann.coleu

Hi,

I'm trying to get nginx caching proxy_pass responses in memcache. When I watch the logs of memcached, I can see nginx making "get" requests with the right key item. But I never seen nginx making "add" request against memcache.

Log Memcached

<30 new auto-negotiating client connection
28: Client using the ascii protocol
<28 get /osm/16/34448/24299.png
>28 END

I activated Nginx debug logs and the debug log file is full of these lines:

Log Nginx

2014/07/04 14:18:52 [debug] 30869#0: *5 srcache_store decides to store the response
2014/07/04 14:18:52 [debug] 30869#0: *5 srcache store header HTTP/1.1 200 OK
2014/07/04 14:18:52 [debug] 30869#0: *3 srcache_store decides to store the response
2014/07/04 14:18:52 [debug] 30869#0: *3 srcache store header HTTP/1.1 200 OK
2014/07/04 14:18:52 [debug] 30869#0: *1 srcache_store decides to store the response
2014/07/04 14:18:52 [debug] 30869#0: *1 srcache store header HTTP/1.1 200 OK

For me it's encouraging. But I'm sure there is nothing stored in memcache. There is nothing in nginx error.log

Nginx configuration

worker_processes  1;

events {
    worker_connections  1024;
}

http {

        upstream local {
            server localhost:11211;
        }
   
        error_log /var/log/nginx/debug.log debug;

        server {
            listen       80;
            server_name  localhost;
            memc_connect_timeout 100ms;
            memc_send_timeout 100ms;
            memc_read_timeout 100ms;

            location = /memc {
                internal;

                set $memc_key $query_string;
                set $memc_exptime 1d;
                memc_pass local;
            }

            location / {
                srcache_fetch GET /memc $uri;
                srcache_store PUT /memc $uri;
                proxy_pass http://localhost:8080;
            }
        }

}

I tried this configuration both on openresty 1.7 and original nginx 1.7.

any idea?

Thanks !

agentzh

Hello!

On Fri, Jul 4, 2014 at 7:40 AM, Yann Coleu wrote:
>             location = /memc {
>                 internal;
>
>                 set $memc_key $query_string;
>                 set $memc_exptime 1d;

This line is guilty. $memc_exptime only expects an integer value for
seconds. No magic like "1d" is allowed here. So ngx_memc returns a 400
error page in your srcache_store subrequests without even talking to
memcached.

Change that line to

    set $memc_exptime 86400;

fixes the issue on my side. And memcached server reports the following
under -vv:

    <30 new auto-negotiating client connection
    30: Client using the ascii protocol
    <30 get /t2
    >30 END
    <30 connection closed.
    <30 new auto-negotiating client connection
    30: Client using the ascii protocol
    <30 set /t2 0 86400 48
    >30 STORED
    <30 connection closed.

Just as expected.

To make debugging such configuration mistakes easier, I've just
committed a patch to ngx_srcache and ngx_memc's git master branches,
respectively, which will now give helpful error messages in your
example:

    [error] 2265#0: *5 variable "$memc_exptime" takes invalid value: 1d, ...
    [error] 2265#0: *5 srcache_store subrequest failed: rc=400 status=0, ...

Thank you for the report.

Best regards,
-agentzh

yann.coleu

Hi,

Many thanks for your help, I guess it works now

<28 new auto-negotiating client connection
28: Client using the ascii protocol
<28 set /osm/18/137754/97637.png 0 1000 488
>28 STORED

Best regards,
Yann.

Le vendredi 4 juillet 2014 16:40:26 UTC+2, Yann Coleu a écrit :

Hi,

I'm trying to get nginx caching proxy_pass responses in memcache. When I watch the logs of memcached, I can see nginx making "get" requests with the right key item. But I never seen nginx making "add" request against memcache.

Log Memcached

<30 new auto-negotiating client connection 28: Client using the ascii protocol <28 get /osm/16/34448/24299.png >28 END

I activated Nginx debug logs and the debug log file is full of these lines:

Log Nginx

2014/07/04 14:18:52 [debug] 30869#0: *5 srcache_store decides to store the response 2014/07/04 14:18:52 [debug] 30869#0: *5 srcache store header HTTP/1.1 200 OK 2014/07/04 14:18:52 [debug] 30869#0: *3 srcache_store decides to store the response 2014/07/04 14:18:52 [debug] 30869#0: *3 srcache store header HTTP/1.1 200 OK 2014/07/04 14:18:52 [debug] 30869#0: *1 srcache_store decides to store the response 2014/07/04 14:18:52 [debug] 30869#0: *1 srcache store header HTTP/1.1 200 OK

For me it's encouraging. But I'm sure there is nothing stored in memcache. There is nothing in nginx error.log

Nginx configuration

worker_processes 1; events { worker_connections 1024; } http { upstream local { server localhost:11211; } error_log /var/log/nginx/debug.log debug; server { listen 80; server_name localhost; memc_connect_timeout 100ms; memc_send_timeout 100ms; memc_read_timeout 100ms; location = /memc { internal; set $memc_key $query_string; set $memc_exptime 1d; memc_pass local; } location / { srcache_fetch GET /memc $uri; srcache_store PUT /memc $uri; proxy_pass http://localhost:8080; } } }

I tried this configuration both on openresty 1.7 and original nginx 1.7.

any idea?

Thanks !