location {{ alertmanager_web_path }}/ {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;

    auth_basic "Authentication required for Alert Manager";
    auth_basic_user_file /etc/nginx/.htpasswd-alertmanager;

    proxy_pass http://localhost:{{ alertmanager_port }}/;
}