英文:
how to limit goroutine
问题
我正在开发一个基于Google API的Gmail客户端。
我通过以下调用获取了标签列表：
r, err := s.gClient.Service.Users.Labels.List(s.gClient.User).Do()
然后，对于每个标签，我需要获取详细信息：
for _, l := range r.Labels {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()}
我希望以更强大的方式处理循环，所以我在循环中实现了一个goroutine：
ch := make(chan label.Label)for _, l := range r.Labels {go func(gmailLabels *gmailclient.Label, gClient *gmail.Client, ch chan<- label.Label) {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()if err != nil {panic(err)}// 对标签 `d` 执行一些操作preparedLabel := ....ch <- preparedLabel}(l, s.gClient, ch)}for i := 0; i < len(r.Labels); i++ {lab := <-chfmt.Printf("Processed %v\n", lab.LabelID)}
这段代码的问题是Gmail API有一个速率限制，所以我会得到以下错误：
panic: googleapi: Error 429: Too many concurrent requests for user, rateLimitExceeded
如何正确处理这种情况？
英文:
I'm developing a gmail client based on google api.
I have a list of labels obtained through this call
r, err := s.gClient.Service.Users.Labels.List(s.gClient.User).Do()
Then, for every label I need to get details
for _, l := range r.Labels {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()}
I'd like to handle the loop in a more powerful way so I have implemented a goroutine in the loop:
ch := make(chan label.Label)for _, l := range r.Labels {go func(gmailLabels *gmailclient.Label, gClient *gmail.Client, ch chan<- label.Label) {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()if err != nil {panic(err)}// Performs some operation with the label `d`preparedLabel := ....ch <- preparedLabel}(l, s.gClient, ch)}for i := 0; i < len(r.Labels); i++ {lab := <-chfmt.Printf("Processed %v\n", lab.LabelID)}
The problem with this code is that gmail api has a rate limit, so, I get this error:
panic: googleapi: Error 429: Too many concurrent requests for user, rateLimitExceeded
What is the correct way to handle this situation?
答案1
得分: 1
只启动10个goroutine，然后在一个goroutine中从一个for循环传递值到另一个goroutine中，通道具有小缓冲区以减少同步时间。
chIn := make(chan label.Label, 20)chOut := make(chan label.Label, 20)for i := 0; i < 10; i++ {go func(gClient *gmail.Client, chIn chan label.Label, chOut chan<- label.Label) {for gmailLabels := range chIn {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()if err != nil {panic(err)}// 对标签 `d` 执行一些操作preparedLabel := ....chOut <- preparedLabel}}(s.gClient, chIn, chOut)}go func(chIn chan label.Label) {defer close(chIn)for _, l := range r.Labels {chIn <- l}}(chIn)for i := 0; i < len(r.Labels); i++ {lab := <-chOutfmt.Printf("Processed %v\n", lab.LabelID)}编辑：这里是一个[playground示例](https://play.golang.org/p/R4b296QOrk)。<details><summary>英文:</summary>How about only starting e.g. 10 goroutines and pass the values in from one for loop in another go routine. The channels have a small buffer to decrease synchronisation time.chIn := make(chan label.Label, 20)chOut := make(chan label.Label, 20)for i:=0;i<10;i++ {go func(gClient *gmail.Client, chIn chan label.Label, chOut chan<- label.Label) {for gmailLabels := range chIn {d, err := s.gClient.Service.Users.Labels.Get(s.gClient.User, l.Id).Do()if err != nil {panic(err)}// Performs some operation with the label `d`preparedLabel := ....chOut <- preparedLabel}}(s.gClient, chIn, chOut)}go func(chIn chan label.Label) {defer close(chIn)for _, l := range r.Labels {chIn <- l}}(chIn)for i := 0; i < len(r.Labels); i++ {lab := <-chOutfmt.Printf("Processed %v\n", lab.LabelID)}EDIT:Here a [playground sample](https://play.golang.org/p/R4b296QOrk).</details>
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