I am trying to use Oauth2-proxy as a gateway to my web site with Google auth. The Oauth login page appears, and you can click "Sign In" which takes you to a Google login page, but after logging in it redirects straight back to the Oauth login page. I suspect it has something to do with cookies but I don't know where I'm going wrong.

NGINX config:

server {
  listen 443;
  server_name my.website.com;

  ssl on;
  ssl_certificate /etc/ssl/my.website.com.pem;
  ssl_certificate_key /etc/ssl/my.website.com.key;

  location /oauth2/ {
    proxy_pass       http://127.0.0.1:4180;
    proxy_set_header Host                    $host;
    proxy_set_header X-Real-IP               $remote_addr;
    proxy_set_header X-Scheme                $scheme;
    proxy_set_header X-Auth-Request-Redirect $request_uri;
  }
  location = /oauth2/auth {
    proxy_pass       http://127.0.0.1:4180;
    proxy_set_header Host             $host;
    proxy_set_header X-Real-IP        $remote_addr;
    proxy_set_header X-Scheme         $scheme;
    proxy_set_header Content-Length   "";
    proxy_pass_request_body           off;
  }

  location / {
    auth_request /oauth2/auth;
    error_page 401 = /oauth2/sign_in;

    # pass information via X-User and X-Email headers to backend,
    # requires running with --set-xauthrequest flag
    auth_request_set $user   $upstream_http_x_auth_request_user;
    auth_request_set $email  $upstream_http_x_auth_request_email;
    proxy_set_header X-User  $user;
    proxy_set_header X-Email $email;

    # if you enabled --pass-access-token, this will pass the token to the backend
    auth_request_set $token  $upstream_http_x_auth_request_access_token;
    proxy_set_header X-Access-Token $token;

    # if you enabled --cookie-refresh, this is needed for it to work with auth_request
    auth_request_set $auth_cookie $upstream_http_set_cookie;
    add_header Set-Cookie $auth_cookie;

    # When using the --set-authorization-header flag, some provider's cookies can exceed the 4kb
    # limit and so the OAuth2 Proxy splits these into multiple parts.
    # Nginx normally only copies the first `Set-Cookie` header from the auth_request to the respon$
    # so if your cookies are larger than 4kb, you will need to extract additional cookies manually.
    auth_request_set $auth_cookie_name_upstream_1 $upstream_cookie_auth_cookie_name_1;

    # Extract the Cookie attributes from the first Set-Cookie header and append them
    # to the second part ($upstream_cookie_* variables only contain the raw cookie content)
    if ($auth_cookie ~* "(; .*)") {
        set $auth_cookie_name_0 $auth_cookie;
        set $auth_cookie_name_1 "auth_cookie_name_1=$auth_cookie_name_upstream_1$1";
    }

    # Send both Set-Cookie headers now if there was a second part
    if ($auth_cookie_name_upstream_1) {
        add_header Set-Cookie $auth_cookie_name_0;
        add_header Set-Cookie $auth_cookie_name_1;
    }
    
    proxy_set_header   X-Forwarded-For $remote_addr;
    proxy_set_header   Host $http_host;
    proxy_pass         "http://127.0.0.1:8888"; # This is where my web server is hosted
  }
}

Oauth2-proxy config:

cookie_secret="" # Filled in with a base64 string
provider="google"
email_domains="*"
client_secret="" # Filled in with Google auth client secret
client_id="" # Filled in with Google auth client ID
cookie_secure="false" # No idea what to set this as, tried both false and true, same result
redirect_url="https://my.website.com/oauth2/auth/"
upstreams="http://127.0.0.1:8888/" # My website server

Oauth2-proxy startup command:

~/oauth2-proxy-v6.1.1.linux-amd64/oauth2-proxy --config=/home/username/work/src/github.com/oauth2-proxy/oauth2-proxy/contrib/local-environment/oauth2-proxy.cfg

Any ideas would be greatly appreciated!

According to the documentation --redirect-url is the OAuth Redirect URL, should be set to supported callback endpoint , e.g. "https://internalapp.yourcompany.com/oauth2/callback".

/oauth2/callback endpoint - the URL used at the end of the OAuth cycle. The oauth app will be configured with this as the callback url.

The actual generated url has a state parameter, that includes the original URL to return back. As I understand, callback retrieves from the state the original (protected by the proxy) url and redirects browser to it.