我正在尝试在 go 中创建一个 http 客户端程序,它会发出许多 http GET 请求。我正在使用缓冲 channel 来限制并发请求的数量。
当我运行程序时,我得到了
获取http://198.18.96.213/: dial tcp 198.18.96.213:80: too many open files
这是我的程序:
package main
import (
"fmt"
"net/http"
"time"
)
func HttpGets(numRequests int, numConcurrent int, url string) map[int]int {
// I want number of requests with each status code
responseStatuses := map[int]int {
100: 0, 101 : 0, 102 : 0, 200 : 0, 201 : 0, 202 : 0, 203 : 0, 204 : 0, 205 : 0,
206 : 0, 207 : 0, 208 : 0, 226 : 0, 300 : 0, 301 : 0, 302 : 0, 303 : 0, 304 : 0,
305 : 0, 306 : 0, 307 : 0, 308 : 0, 400 : 0, 401 : 0, 402 : 0, 403 : 0, 404 : 0,
405 : 0, 406 : 0, 407 : 0, 408 : 0, 409 : 0, 410 : 0, 411 : 0, 412 : 0, 413 : 0,
414 : 0, 415 : 0, 416 : 0, 417 : 0, 421 : 0, 422 : 0, 423 : 0, 424 : 0, 425 : 0,
426 : 0, 427 : 0, 428 : 0, 429 : 0, 430 : 0, 431 : 0, 500 : 0, 501 : 0, 502 : 0,
503 : 0, 504 : 0, 505 : 0, 506 : 0, 507 : 0, 508 : 0, 509 : 0, 510 : 0, 511 : 0,
}
reqsDone := 0
ch := make(chan *http.Response, numConcurrent)
for i := 0; i < numRequests; i++ {
go func(url string) {
client := &http.Client{}
req, reqErr := http.NewRequest("GET", url, nil)
if reqErr != nil {
fmt.Println(reqErr)
}
// adding connection:close header hoping to get rid
// of too many files open error. Found this in http://craigwickesser.com/2015/01/golang-http-to-many-open-files/
req.Header.Add("Connection", "close")
resp, err := client.Do(req)
if (err !=nil) {
fmt.Println(err)
}
ch <- resp
}(url)
}
for {
select {
case r := <-ch:
reqsDone += 1 // probably needs a lock?
status := r.StatusCode
if _, ok := responseStatuses[status]; ok {
responseStatuses[status] += 1
} else {
responseStatuses[status] = 1
}
r.Body.Close() // trying to close body hoping to get rid of too many files open error
if (reqsDone == numRequests) {
return responseStatuses
}
}
}
return responseStatuses
}
func main() {
var numRequests, numConcurrent = 500, 10
url := "http://198.18.96.213/"
beginTime := time.Now()
results := HttpGets(numRequests, numConcurrent, url)
endTime := time.Since(beginTime)
fmt.Printf("Total time elapsed: %s\n", endTime)
for k,v := range results {
if v!=0 {
fmt.Printf("%d : %d\n", k, v)
}
}
}
如何确保文件/soce 已关闭,以便在发出多个请求时不会出现此错误?
最佳答案
基本上,您生成了 100 个 goroutine,这些 goroutine 将启动连接 block ,直到它们关闭。
这是一个快速(而且非常丑陋)的工作代码:
var (
responseStatuses = make(map[int]int, 63)
reqsDone = 0
urlCh = make(chan string, numConcurrent)
ch = make(chan *http.Response, numConcurrent)
)
log.Println(numConcurrent, numRequests, len(responseStatuses))
for i := 0; i < numConcurrent; i++ {
go func() {
for url := range urlCh {
client := &http.Client{}
req, reqErr := http.NewRequest("GET", url, nil)
if reqErr != nil {
fmt.Println(reqErr)
}
// adding connection:close header hoping to get rid
// of too many files open error. Found this in http://craigwickesser.com/2015/01/golang-http-to-many-open-files/
req.Header.Add("Connection", "close")
resp, err := client.Do(req)
if err != nil {
fmt.Println(err)
}
ch <- resp
}
}()
}
go func() {
for i := 0; i < numRequests; i++ {
urlCh <- url
}
close(urlCh)
}()
关于http - 发出 http 请求时打开的文件太多,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31527948/