A brief analysis of the principles and implementation methods of golang request merging

With the continuous development of Internet technology, front-end development and back-end development technologies are becoming more and more complex. Processing the original N requests may lead to resource waste and reduced efficiency, so we need a better way to process requests and improve program performance. In Golang, request merging technology can be used to achieve this purpose. This article will introduce the principle, implementation and use of Golang request merging.

1. The principle of request merging

In network communication, each request needs to connect to the server, receive data, return data, etc. For multiple requests, these operations need to be performed multiple times, causing waste. If we merge multiple requests into one request and send it to the server, the server only needs to perform the connection, reception, and return operations once to obtain the return values ​​of multiple requests. This will increase the efficiency of the program and reduce the number of requests.

2. Implement request merging

In Golang, the most commonly used tool for merging requests is the "Golang Group Cache" library. It is a very flexible tool and you can define what you need. Specific functions.

Before using it, we need to install the library first:

go get "github.com/golang/groupcache"

1. Define the data structure

Define a Request structure to save the data of each request Information, including requested URL, parameters to be passed, returned results, etc.

type Request struct {
    url    string // 请求URL
    params []interface{} // 参数
    result chan Result // 返回结果
}

Among them, Result is a structure used to save the status of the request result.

type Result struct {
    Value interface{}
    Err   error
}

2. Define request merging function

Method to merge multiple requests into one request, use the Group's Do function provided by the GroupCache library, which can automatically check whether There is the same request waiting for a response, and if there is one, the same response is returned. Otherwise, the request is sent to the server. After the server completes the execution, the result is returned to the result channel.

func (r *Request) Do() (*Result, error) {
    group := groupcache.NewGroup("requests", 64<<20, groupcache.GetterFunc(
        func(ctx groupcache.Context, key string, dest groupcache.Sink) error {
            req := r.params[0].(Request)
            value, err := http.Get(req.url)
            if err != nil {
                return err
            }
            dest.Set(value)
            return nil
        }))
    var res Result
    if err := group.Get(nil, r.url, groupcache.AllocatingByteSliceSink(&res.Value)); err != nil {
        res.Err = err
    }
    return &res, res.Err
}

Among them, 64<<20 is the maximum cache space for a request. groupcache.GetterFunc is a callback function used to obtain the request results.

3. Waiting for the request to return the result

While waiting for the request result, we can use channels to process it.

func main() {
    result := make(chan Result)
    go func(req *Request) {
        res, err := req.Do()
        if err != nil {
            log.Fatal(err)
        }
        result <- *res
    }(req)
    res := <-result // 等待响应结果
    fmt.Println(res)
}

4. Use request merging to handle a large number of requests

Finally, we can merge multiple requests into one request to handle a large number of requests.

func main() {
    requests := make([]Request, 0) 
    for i := 0; i < 100; i++ {
        requests = append(requests, Request{url: "https://www.example.com", params: nil})
    }
    result := make(chan Result)
    for _, req := range requests {
        go func(req *Request) {
            res, err := req.Do()
            if err != nil {
                log.Fatal(err)
            }
            result <- *res
        }(&req)
    }
    for i := 0; i < len(requests); i++ {
        res := <-result
        fmt.Println(res)
    }
}

3. Summary

In network communication, request merging is a very effective method, which can greatly improve program efficiency and reduce the number of requests. Although in Golang, you can use the GroupCache library to implement request merging, merging requests will affect the request processing time. We must use this technology reasonably, otherwise it will reduce the performance of the program.

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