Today a good old friend, Alex, sent me a “Bat signal” asking for help with an unusual NGINX configuration, I wonder why my friends only remembers me during “weird” incidents :P
Basically the requirement was to run a multiple copies of a legacy application on the same URL as it does not support folder prefix or subdomains. The desired functionality was that /app1 configures nginx to use backend1 and return to /, and all the subsequent requests on / should be sent to backend1, the same with /app2 to backend2 and /app3 to backend3.
So the solution we designed is:
A request to http://server/app1, sets a cookie to be used for backend selection, and redirect to /. subsequent requests to /, will use the cookie value and select the backend based on it.
So on this example it was used a combination of map, regexp named matches and cookies using NGINX.
The configuration below achieves this functionality, mapping /app[0-9] to specific backend listed on the map { }
| map $cookie_beid $backend { | |
| default www.globo.com:80; | |
| 1 www.uol.com.br:80; | |
| 2 www.ig.com.br:80; | |
| 3 www.terra.com.br:80; | |
| } | |
| server { | |
| listen 80 default; | |
| server_name _; | |
| resolver 4.2.2.2; | |
| location ~ ^/app(?<beid>[0-9]+) { | |
| add_header Set-Cookie "beid=${beid};Max-Age=31536000"; | |
| return 301 /; | |
| } | |
| location / { | |
| add_header X-Backend $backend; | |
| add_header X-BeID $cookie_beid; | |
| proxy_pass http://$backend; | |
| } | |
| } |
Thanks!