Storing $server_addr in a variable VS using it directly in location block

[Valentin V. Bartenev]

On Tuesday 14 July 2015 21:46:58 justink101 wrote:
> According to the documentation getting the value of $server_addr to set a
> response header makes a system call, and can impact performance
> negativelyset $ip $server_addr;
> 
>     server {
>         location /health {
>             add_header Backend $server_addr;
>             return 200;
>         }
>     }
> 
> Would the following be a better solution, and eliminate the system call on
> every request?
> 
>     server {
>         set $ip $server_addr;
> 
>         location /health {
>             add_header Backend $ip always;
>             return 200;
>         }
>     }
> 

No, it wouldn't.  The "set" directive also is executed on every request.

  wbr, Valentin V. Bartenev