Hi all,

I want to read some remote values via HTTP into nginx config variables, just once at nginx startup / reload time, and pass them as fastcgi_params into PHP scripts. I control the remote system, so I'll know if it needs to re-read and can send a HUP to nginx. I don't need it to happen every request though, because the value won't change for long periods - but it will change sometimes, and I don't want to have push more config out to multiple nginx servers if I can avoid it.

Is there a way to do this that doesn't create problems?

Here's what I've tried so far.

This first one doesn't work, because the "API [is] disabled in the context of set_by_lua*":

set_by_lua $config_variable "
local result = ngx.location.capture('http://url.to.fetch/')
return result
"

(Same with ngx.socket.*)

This next one works; it feels horrible to do this but if it was just once at start-up, it might be OK - but this executes for every incoming request (confirmed by using /bin/date as the 'command' and just hitting refresh):

set_by_lua $config_variable "
local command = "/usr/bin/curl http://url.to.fetch/"
local handle = io.popen(command)
local result = handle:read("*a")
handle:close()
return result
"

Same for this one, it executes for every request:

perl_set $config_variable '
sub {
$var = `/bin/date`;
return $var;
}
'

Is there a good way to do this, that only executes once, and doesn't have horrible shell interactions?

Thanks very much for your help,
Igor