CODEWITHSUNDEEP
nginxauth-request
Mike Emery
Mike Emery

Reputation: 837

nginx auth_request error handling (unset error_page?)

When using nginx auth_request, only 4 return codes are accepted: 2xx, 401, 403 and 500. Handling these requires setting error_page. This is fine for auth_request, but all downstream apps returning these codes will end up using the same error_page handling.

Example:

location /test {
  auth_request /foo;
  error_page 500 /its-broke.html;
  proxy_pass http://bar;
}

If auth_request to /foo returns 500, the its-broke.html is shown. This is the behavior I want. However, if bar returns 500 its-broke.html is also shown. I don't want this. Instead, I want bar's 500 error response to be transmitted through to the browser.

auth_request will catch any 5xx and handle it as 500, so I can't just have foo return 520. That results in the following error and 500 is returned anyway: 

auth request unexpected status: 520 while sending to client

Any ideas for getting around this? I can't find a way to un-set error_page before the proxy pass either.

Upvotes: 2

Views: 4639

Answers (1)

Tarun Lalwani
Tarun Lalwani

Reputation: 146630

You can do that with some effort though

events {
    worker_connections 1024;
}
http {

    server {

        listen 80;

        location @autherror {

            return 500 "Auth returned 500";
        }

        location @proxy_api {

            proxy_pass http://127.0.0.1:8081;
        }

        location / {

            location /test {

                auth_request /auth;
                error_page 500 = @autherror;
                try_files dummy_non_existing_url = @proxy_api;
            }

        }
        location /auth {

            return 200 "auth passed";
        }

    }

    server {

        listen 8081;
        location / {
            return 200 "You came to $uri";
        }
        location /test2 {
            return 500 "Error from API";
        }
    }
}

Result from the API test is

$ curl localhost/test
You came to /test

$ curl localhost/test2
Error from API

Now if I change return 200 "auth passed"; to return 500 "auth failed"; to simulate authentication 500 error, i get

$ curl localhost/test
Auth returned 500

Upvotes: 2

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