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Accepted
Mike Purcell
Asked: 2019-08-14 11:15:34 +0800 CST

NGinx add Retry-After header to ONLY 429 Responses

  • 772

Given the following NGinx config, how would I alter it to issue a Retry-After header to ONLY 429 reponses?

limit_req_zone $binary_remote_addr zone=ip:10m rate=5r/s;
limit_req_status 429;
limit_conn_status 429;

server {

    listen 80;

    location /api {

        limit_req zone=ip burst=12 nodelay;

        proxy_pass http://website;
    }
}
nginx

1 Answers

  1. Best Answer

    There is variable $status that holds response status value. You could use map directive to define another variable that holds retry delay and use add_header directive.

    add_header Retry-After $retry_after always;

    add_header will not send header if value (second argument) is empty. And we need always flag, otherwise it will not set header for 429 status code.

    Full example:

    limit_req_zone $binary_remote_addr zone=ip:10m rate=5r/s;
limit_req_status 429;
limit_conn_status 429;

map $status $retry_after {
    default '';
    429 '120';
}

server {
    listen 80;
    location /api {
        limit_req zone=ip burst=12 nodelay;
        proxy_pass http://website;
        add_header Retry-After $retry_after always;
    }
}
    • 4