thread safety/race conditions when using ngx.ctx in different directives

gauravphoenix · 2014-11-19T10:09:55+00:00

On Mon, Nov 17, 2014 at 2:23 PM, Yichun Zhang (agentzh) <age...@gmail.com> wrote:Hello! On Mon, Nov 17, 2014 at 2:06 PM, David Birdsong wrote: >...

thread safety/race conditions when using ngx.ctx in different directives

gauravphoenix

Let's say I am setting a flag in access_by_lua and accessing it body_filter_by_lua like below-

location / {

access_by_lua '
 ngx.ctx.flag = 1
';

body_filter_by_lua ' 
 if ngx.ctx.flag ==1 then
   -- do processing here
 end

'
}

Is it guaranteed that if condition will in body_filter_by_lua will evaluate to true only for the requests where ngx.ctx.flag is 1?

manchev

Sure, it's even in the documentation [1]:

That is, the ngx.ctx.foo entry persists across the rewrite, access, and content phases of a request.
Every request, including subrequests, has its own copy of the table.

[1]: https://github.com/openresty/lua-nginx-module#ngxctx

Best,
Vladislav

On Wed, Nov 19, 2014 at 4:09 AM, Gaurav Kumar <gaurav...@gmail.com> wrote:

Let's say I am setting a flag in access_by_lua and accessing it body_filter_by_lua like below-

location / { access_by_lua ' ngx.ctx.flag = 1 '; body_filter_by_lua ' if ngx.ctx.flag ==1 then -- do processing here end ' }

Is it guaranteed that if condition will in body_filter_by_lua will evaluate to true only for the requests where ngx.ctx.flag is 1?

.