Adding cachekey to log_format directive
Wouter van der Schagt
nginx-forum at nginx.us
Tue Nov 13 05:55:31 UTC 2012
Good morning,
I'm trying to add the generated cache key of a proxied request to a
log_format directive. From what I can tell, this variable is not normally
available when logging requests so I've to modify the proxy module in
ngx_http_proxy_module.c.
So far I've added "cachekey" to the typedef struct: ngx_http_proxy_vars_t so
that ngx_http_proxy_set_var can set it.
I've added the declaration:
static ngx_int_t ngx_http_proxy_cachekey_variable(ngx_http_request_t *r,
ngx_http_variable_value_t *v, uintptr_t data); and in the corresponding
function (which is basically a copy of ngx_http_proxy_host_variable), I do:
v->len = ctx->vars.cachekey.len;
v->data = ctx->vars.cachekey.data;
I've also added:
{ ngx_string("proxy_cachekey"), NULL, ngx_http_proxy_cachekey_variable, 0,
NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0
},
to ngx_http_proxy_vars[] so that proxy_cachekey is available for use in the
log_format directive.
Finally in; ngx_http_proxy_set_var(ngx_url_t *u, ngx_http_proxy_vars_t *v)
I'm guessing I've to set the key somewhere here:
v->cachekey.len = ??;
v->cachekey.data = ??;
The question I have is, how do I get the generated cache key in the
v.cachekey.data field? If I populate these variables with arbitrary data I
can see its being logged correctly so am confident I'm in the right place.
Any suggestion would be appreciated,
Sincerely,
- WS
Posted at Nginx Forum: http://forum.nginx.org/read.php?2,232747,232747#msg-232747
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