How to use Nginx for request rate limiting and flow control

How to use Nginx for request rate limiting and flow control

Nginx is a lightweight web server and proxy server with high performance and high concurrency processing capabilities, and is suitable for building large-scale distributed systems. In practical applications, in order to ensure the stability of the server, we often need to limit the rate and flow of requests. This article will introduce how to use Nginx for request rate limiting and flow control, and provide code examples.

1. Request rate limit

Request rate limit refers to limiting the number of requests that each client can initiate within a certain period of time. This can prevent a client from requesting the server too frequently, causing excessive consumption of server resources.

First, add the following code to the Nginx configuration file:

http {
    # 定义限速区域，以client IP为准
    limit_req_zone $binary_remote_addr zone=limit:10m rate=10r/s;
    
    server {
        listen 80;
        
        # 使用limit_req模块限制请求速率
        location / {
            limit_req zone=limit burst=20;
            proxy_pass http://backend;
        }
    }
}

The above configuration will limit each client to initiate a maximum of 10 requests in 1 second, and requests exceeding the limit will be delayed. deal with.

2. Flow control

Flow control refers to scheduling and offloading requests through Nginx to optimize server load and improve user experience. By rationally allocating server resources, you can ensure that different types of requests can be handled appropriately.

The following is a sample code for flow control:

http {
    # 定义后端服务器
    upstream backend {
        server backend1;
        server backend2;
    }
    
    server {
        listen 80;
        
        location /api/ {
            # 根据请求路径进行分流
            if ($request_uri ~* "^/api/v1/") {
                proxy_pass http://backend1;
            }
            if ($request_uri ~* "^/api/v2/") {
                proxy_pass http://backend2;
            }
        }
        
        location / {
            # 静态文件请求走本地硬盘
            try_files $uri $uri/ =404;
        }
    }
}

The above configuration will selectively forward traffic to the backend server based on the requested path. For example, requests starting with /api/v1/ will be forwarded to the backend1 server, and requests starting with /api/v2/ will be forwarded to the backend2 server.

Can be combined with other modules of Nginx to perform more complex traffic control according to actual needs, such as fine-grained control of traffic through HTTP access frequency, user IP or cookies.

Summary:

Through the above examples, we learned how to use Nginx for request rate limiting and flow control. Request rate limiting can prevent malicious requests from causing excessive pressure on the server, while flow control can reasonably allocate server resources according to different needs and improve user experience. By properly configuring Nginx, we can better ensure the stability and performance of the server.

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