How to implement Nginx limit request rate configuration

How to implement Nginx limit request rate configuration

Nginx is a high-performance web server that can limit and control requests through configuration. In practical applications, in order to protect server resources, it is often necessary to limit the request rate. This article will introduce how to implement request rate limiting in Nginx.

1. Use the HttpLimitReqModule module

Nginx provides the HttpLimitReqModule module, which can be used to limit the request rate. Before starting the configuration, you need to ensure that the HttpLimitReqModule module has been installed.

1. Edit Nginx configuration file

Open the Nginx configuration file, usually located at /etc/nginx/nginx.conf, find the http section, and add the following configuration:

http {
    ...
    limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;

    server {
        ...
    }
}

limit_req_zone is used to define the name and size of the restricted area, and $binary_remote_addr indicates using the client's IP address as the restricted keyword. zone=one:10m means using a restricted area named one with a size of 10MB. rate=1r/s means that the request rate is limited to 1 per second.

2. Configuring request limits

Where request limits are required, add the limit_req directive to limit the request rate. For example, to limit the request rate to 10 requests/second, you can add the following configuration in the server segment: The

location / {
    limit_req zone=one burst=5;
    ...
}

limit_req directive is used to apply the request limit, the zone parameter specifies the name of the restriction zone used, and the burst parameter specifies the same time Number of requests processed. The above configuration indicates that if the number of requests exceeds 10/second, a 503 error will be returned.

3. Reload Nginx configuration

After completing the configuration, you need to reload the Nginx configuration to make it effective. You can use the following command to check and reload the configuration:

$ nginx -t    # 检查配置是否正确
$ nginx -s reload    # 重新加载配置

2. Use the ngx_http_limit_req_module module

In addition to the HttpLimitReqModule module, you can also use the ngx_http_limit_req_module module to limit the request rate. This module provides more flexible configuration options.

1. Edit Nginx configuration file

Open the Nginx configuration file, find the http segment, and add the following configuration:

http {
    ...
    limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;
    
    server {
        ...
    }
}

This configuration is the same as the HttpLimitReqModule module, A restricted area named one is defined, with a size of 10MB and a request rate limit of 1/second.

2. Configuring request limits

Where request limits are required, add the limit_req directive to limit the request rate. For example, to limit the request rate to 10 requests/second, you can add the following configuration in the server segment: The

location / {
    limit_req zone=one burst=5;
    ...
}

limit_req directive is used to apply the request limit, the zone parameter specifies the name of the restriction zone used, and the burst parameter specifies the same time Number of requests processed.

3. Reload Nginx configuration

After completing the configuration, you need to reload the Nginx configuration to make it effective. You can use the following commands to check and reload the configuration.

$ nginx -t    # 检查配置是否正确
$ nginx -s reload    # 重新加载配置

3. Use lua scripts to extend request limits

Nginx also supports the use of lua scripts to extend request limits. By writing custom Lua scripts, more flexible and complex request limiting strategies can be implemented.

1. Install the lua module

First, you need to make sure that the Nginx lua module has been installed.

2. Write lua script

In the Nginx configuration file, add the following configuration:

http {
    ...
    lua_shared_dict limit_req_store 10m;
    
    server {
        ...
        
        location / {
            access_by_lua_block {
                local limit_req = require "resty.limit.req"
                local lim, err = limit_req.new("limit_req_store", 1, 1)
                if not lim then
                    ngx.log(ngx.ERR, "failed to instantiate a resty.limit.req object: ", err)
                    return ngx.exit(500)
                end
                local key = ngx.var.binary_remote_addr
                local delay, err = lim:incoming(key, true)
                if not delay then
                    if err == "rejected" then
                        return ngx.exit(503)
                    end
                    ngx.log(ngx.ERR, "failed to limit req: ", err)
                    return ngx.exit(500)
                end
                if delay >= 0.001 then
                    ngx.sleep(delay)
                end
            }
            ...
        }
    }
}

This configuration uses the lua_shared_dict directive to define a limit_req_store Shared memory area, size is 10MB.

3. Reload Nginx configuration

After completing the configuration, reload the Nginx configuration to make it effective.

4. Summary

This article introduces three ways to implement Nginx request rate limit, namely using the HttpLimitReqModule module, ngx_http_limit_req_module module and lua script. Through appropriate configuration and restriction policies, server resources can be effectively protected and malicious requests can be prevented from causing excessive load on the server. In actual applications, you can choose an appropriate method to limit the request rate according to specific needs.

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