how can I limit the number of current requests?

[wangcn]

For example, I allow up to 2000 current connections and reject excess requests.

[nazwa]

You could write a middleware that tries to insert into a buffered channel every time a new connection is made.

(this is just proof of concept, not valid syntax)

func LimitMiddleware() gin.HandlerFunc {
     // create a buffered channel with 2000 spaces
     semaphore := make(chan bool, 2000) 


    return func (c *gin.Context) {        
        select {
            case semaphore  <- true: // Try putting a new val into our semaphore
                // Ok, managed to get a space in queue. execute the handler
                c.Next()

                // Don't forget to release a handle
                <-semaphore 
            default:
                 // Buffer full, so drop the connection. Return whatever status you want here
                 return
        }
    }
}

[easonlin404]

@wangcn I have written gin's limit middleware to limit the number of current requests and it can better handle requests limit when panic occurs, you can use it as follows:

package main

import (
	"github.com/easonlin404/limit"
	"github.com/gin-gonic/gin"
)

func main() {

	r := gin.Default()
	r.Use(limit.Limit(200)) // limit the number of current requests

	r.GET("/", func(c *gin.Context) {
		// your code
	})

	r.Run()
}

[ammario]

Using sync/atomic may be preferable here since your're never blocking.